Google Git
Sign in
gnu / gcc.git / 7c99de1c439dbb149cc6a33a214f22f2df1c88f3 / . / gcc / m2 / gm2-compiler / ppg.mod
blob: cd804855d8da2c9650fa018028e55fe74db8f81a [file] [log] [blame]
(* ppg.mod master source file of the ebnf parser generator.
Copyright (C) 2003-2025 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.
This file is part of GNU Modula-2.
GNU Modula-2 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GNU Modula-2 is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Modula-2; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. *)
MODULE ppg ;
FROM PushBackInput IMPORT WarnError, WarnString, GetColumnPosition, GetCurrentLine ;
FROM bnflex IMPORT IsSym, SymIs, TokenType, GetCurrentToken, GetCurrentTokenType, GetChar, PutChar,
SkipWhite, SkipUntilEoln, AdvanceToken, IsReserved, OpenSource, CloseSource,
PushBackToken, SetDebugging ;
FROM StrLib IMPORT StrCopy, StrEqual, StrLen, StrConCat ;
FROM Storage IMPORT ALLOCATE, DEALLOCATE ;
FROM NameKey IMPORT Name, MakeKey, WriteKey, LengthKey, GetKey, KeyToCharStar, NulName ;
FROM NumberIO IMPORT CardToStr, WriteCard ;
FROM SymbolKey IMPORT InitTree, SymbolTree, PutSymKey, GetSymKey, ForeachNodeDo, ContainsSymKey, NulKey ;
FROM Lists IMPORT InitList, IsItemInList, IncludeItemIntoList, RemoveItemFromList, KillList, List ;
FROM DynamicStrings IMPORT String, InitString, KillString, ConCat, Mark, ConCatChar,
InitStringCharStar, char, Length ;
FROM ASCII IMPORT nul, lf, tab ;
FROM StrIO IMPORT WriteString, WriteLn ;
FROM StdIO IMPORT Write ;
FROM Debug IMPORT Halt ;
FROM Args IMPORT GetArg, Narg ;
FROM SYSTEM IMPORT WORD ;
FROM libc IMPORT exit ;
IMPORT Output ;
CONST
MaxCodeHunkLength = 8192 ;
MaxFileName = 8192 ;
MaxString = 8192 ;
DefaultRecovery = TRUE ; (* default is to generate a parser which will recover from errors. *)
MaxElementsInSet = 32 ;
(* formatting constants *)
BaseRightLimit = 75 ;
BaseRightMargin = 50 ;
BaseNewLine = 3 ;
TYPE
ElementType = (idel, tokel, litel) ;
m2condition = (m2none, m2if, m2elsif, m2while) ;
TraverseResult = (unknown, true, false) ;
IdentDesc = POINTER TO RECORD
definition: ProductionDesc ; (* where this idents production is defined *)
name : Name ;
line : CARDINAL ;
END ;
SetDesc = POINTER TO RECORD
next : SetDesc ;
CASE type: ElementType OF
idel : ident : IdentDesc |
tokel,
litel : string: Name
END
END ;
(* note that epsilon refers to whether we can satisfy this component part
of a sentance without consuming a token. Reachend indicates we can get
to the end of the sentance without consuming a token.
For expression, statement, productions, terms: the epsilon value should
equal the reachend value but for factors the two may differ.
*)
FollowDesc = POINTER TO RECORD
calcfollow : BOOLEAN ; (* have we solved the follow set yet? *)
follow : SetDesc ; (* the follow set *)
reachend : TraverseResult ; (* can we see the end of the sentance (due to multiple epsilons) *)
epsilon : TraverseResult ; (* potentially no token may be consumed within this component of the sentance *)
line : CARDINAL ;
END ;
TermDesc = POINTER TO termdesc ;
ExpressionDesc = POINTER TO RECORD
term : TermDesc ;
followinfo: FollowDesc ;
line : CARDINAL ;
END ;
StatementDesc = POINTER TO RECORD
ident : IdentDesc ;
expr : ExpressionDesc ;
followinfo : FollowDesc ;
line : CARDINAL ;
END ;
CodeHunk = POINTER TO RECORD
codetext : ARRAY [0..MaxCodeHunkLength] OF CHAR ;
next : CodeHunk ;
END ;
CodeDesc = POINTER TO RECORD
code : CodeHunk ;
indent : CARDINAL ; (* column of the first % *)
line : CARDINAL ;
END ;
FactorType = (id, lit, sub, opt, mult, m2) ;
FactorDesc = POINTER TO RECORD
followinfo: FollowDesc ;
next : FactorDesc ; (* chain of successive factors *)
line : CARDINAL ;
pushed : FactorDesc ; (* chain of pushed code factors *)
CASE type: FactorType OF
id : ident : IdentDesc |
lit : string: Name |
sub,
opt,
mult: expr : ExpressionDesc |
m2 : code : CodeDesc ;
END
END ;
termdesc = RECORD
factor : FactorDesc ;
next : TermDesc ; (* chain of alternative terms *)
followinfo: FollowDesc ;
line : CARDINAL ;
END ;
ProductionDesc = POINTER TO RECORD
next : ProductionDesc ; (* the chain of productions *)
statement : StatementDesc ;
first : SetDesc ; (* the first set *)
firstsolved : BOOLEAN ;
followinfo : FollowDesc ;
line : CARDINAL ;
description : Name ;
END ;
DoProcedure = PROCEDURE (ProductionDesc) ;
VAR
LastLineNo : CARDINAL ;
Finished,
SuppressFileLineTag,
KeywordFormatting,
PrettyPrint,
EmitCode,
Texinfo,
Sphinx,
FreeDocLicense,
Debugging,
WasNoError : BOOLEAN ;
LinePrologue,
LineEpilogue,
LineDeclaration : CARDINAL ;
CodePrologue,
CodeEpilogue,
CodeDeclaration : CodeHunk ;
CurrentProduction,
TailProduction,
HeadProduction : ProductionDesc ;
CurrentExpression : ExpressionDesc ;
CurrentTerm : TermDesc ;
CurrentFactor : FactorDesc ;
CurrentIdent : IdentDesc ;
CurrentStatement : StatementDesc ;
CurrentSetDesc : SetDesc ;
ReverseValues,
Values, (* tree of tokens and their ORD value *)
ReverseAliases,
Aliases : SymbolTree ;
ModuleName : Name ;
LastLiteral : Name ;
LastIdent : Name ;
SymIsProc, (* the name of the SymIs function tests and consumes token *)
TokenTypeProc, (* the name of the function which yields the current token type *)
ErrorProcArray,
ErrorProcString : Name ; (* the name of the error procedures *)
ArgName,
FileName : ARRAY [0..MaxFileName] OF CHAR ;
OnLineStart,
BeginningOfLine : BOOLEAN ;
Indent : CARDINAL ;
EmittedVar : BOOLEAN ; (* have we written VAR yet? *)
ErrorRecovery : BOOLEAN ; (* do we want to recover from parsing errors? *)
LargestValue : CARDINAL ; (* the number of tokens we are using. *)
InitialElement : BOOLEAN ; (* used to determine whether we are writing *)
(* the first element of a case statement. *)
ParametersUsed : BITSET ; (* which parameters have been used? *)
(* % declaration *)
(*
AddEntry - adds an entry into, t, containing [def:value].
*)
PROCEDURE AddEntry (VAR t: SymbolTree; def, value: Name) ;
BEGIN
IF ContainsSymKey(t, def)
THEN
WarnError1("already seen a definition for token '%s'", def)
ELSE
PutSymKey(t, def, value)
END
END AddEntry ;
(*
Format1 - converts string, src, into, dest, together with encapsulated
entity, n. It only formats the first %s or %d with n.
*)
PROCEDURE Format1 (src: ARRAY OF CHAR; n: WORD; VAR dest: ARRAY OF CHAR) ;
VAR
HighSrc,
HighDest,
i, j : CARDINAL ;
str : ARRAY [0..MaxString] OF CHAR ;
BEGIN
HighSrc := StrLen(src) ;
HighDest := HIGH(dest) ;
i := 0 ;
j := 0 ;
WHILE (i<HighSrc) AND (src[i]#nul) AND (j<HighDest) AND (src[i]#'%') DO
dest[j] := src[i] ;
INC(i) ;
INC(j)
END ;
IF (i+1<HighSrc) AND (src[i]='%') AND (j<HighDest)
THEN
IF src[i+1]='s'
THEN
dest[j] := nul ;
GetKey(n, str) ;
StrConCat(dest, str, dest) ;
j := StrLen(dest) ;
INC(i, 2)
ELSIF src[i+1]='d'
THEN
dest[j] := nul ;
CardToStr(n, 0, str) ;
StrConCat(dest, str, dest) ;
j := StrLen(dest) ;
INC(i, 2)
ELSE
dest[j] := src[i] ;
INC(i) ;
INC(j)
END
END ;
(* and finish off copying src into dest *)
WHILE (i<HighSrc) AND (src[i]#nul) AND (j<HighDest) DO
dest[j] := src[i] ;
INC(i) ;
INC(j)
END ;
IF j<HighDest
THEN
dest[j] := nul
END ;
END Format1 ;
(*
WarnError1 -
*)
PROCEDURE WarnError1 (a: ARRAY OF CHAR; n: WORD) ;
VAR
line: ARRAY [0..MaxString] OF CHAR ;
BEGIN
Format1(a, n, line) ;
WarnError(line)
END WarnError1 ;
(*
PrettyFollow -
*)
PROCEDURE PrettyFollow (start, end: ARRAY OF CHAR; f: FollowDesc) ;
BEGIN
IF Debugging
THEN
Output.WriteString(start) ;
IF f#NIL
THEN
WITH f^ DO
IF calcfollow
THEN
Output.WriteString('followset defined as:') ;
EmitSet(follow, 0, 0)
END ;
CASE reachend OF
true : Output.WriteString(' [E]') |
false: Output.WriteString(' [C]') |
unknown: Output.WriteString(' [U]')
ELSE
END ;
CASE epsilon OF
true : Output.WriteString(' [e]') |
false : |
unknown: Output.WriteString(' [u]')
ELSE
END
END
END ;
Output.WriteString(end)
END
END PrettyFollow ;
(*
NewFollow - creates a new follow descriptor and returns the data structure.
*)
PROCEDURE NewFollow () : FollowDesc ;
VAR
f: FollowDesc ;
BEGIN
NEW(f) ;
WITH f^ DO
follow := NIL ;
reachend := unknown ;
epsilon := unknown ;
END ;
RETURN( f )
END NewFollow ;
(*
AssignEpsilon - assigns the epsilon value and sets the epsilon to value,
providing condition is TRUE.
*)
PROCEDURE AssignEpsilon (condition: BOOLEAN; f: FollowDesc; value: TraverseResult) ;
BEGIN
WITH f^ DO
IF condition AND (value#unknown) AND (epsilon=unknown)
THEN
epsilon := value ;
Finished := FALSE
END
END
END AssignEpsilon ;
(*
GetEpsilon - returns the value of epsilon
*)
PROCEDURE GetEpsilon (f: FollowDesc) : TraverseResult ;
BEGIN
IF f=NIL
THEN
Halt('why is the follow info NIL?',
__FILE__, __FUNCTION__, __LINE__)
ELSE
RETURN( f^.epsilon )
END
END GetEpsilon ;
(*
AssignReachEnd - assigns the reachend value providing that, condition, is TRUE.
*)
PROCEDURE AssignReachEnd (condition: BOOLEAN; f: FollowDesc; value: TraverseResult) ;
BEGIN
IF condition
THEN
WITH f^ DO
IF (reachend=unknown) AND (value#unknown)
THEN
reachend := value ;
Finished := FALSE
END
END
END
END AssignReachEnd ;
(*
GetReachEnd - returns the value of reachend
*)
PROCEDURE GetReachEnd (f: FollowDesc) : TraverseResult ;
BEGIN
IF f=NIL
THEN
Halt('why is the follow info NIL?',
__FILE__, __FUNCTION__, __LINE__)
ELSE
RETURN( f^.reachend )
END
END GetReachEnd ;
(*
AssignFollow - assigns the follow set and sets the calcfollow to TRUE.
*)
PROCEDURE AssignFollow (f: FollowDesc; s: SetDesc) ;
BEGIN
WITH f^ DO
IF calcfollow
THEN
Halt('why are we reassigning this follow set?',
__FILE__, __FUNCTION__, __LINE__)
END ;
follow := s ;
calcfollow := TRUE
END
END AssignFollow ;
(*
GetFollow - returns the follow set.
*)
PROCEDURE GetFollow (f: FollowDesc) : SetDesc ;
BEGIN
IF f=NIL
THEN
Halt ('why is the follow info NIL?',
__FILE__, __FUNCTION__, __LINE__)
ELSE
WITH f^ DO
IF calcfollow
THEN
RETURN( follow )
ELSE
Halt('not calculated the follow set yet..',
__FILE__, __FUNCTION__, __LINE__)
END
END
END
END GetFollow ;
(*
NewProduction - creates a new production and returns the data structure.
*)
PROCEDURE NewProduction () : ProductionDesc ;
VAR
p: ProductionDesc ;
BEGIN
NEW(p) ;
IF TailProduction#NIL
THEN
TailProduction^.next := p
END ;
TailProduction := p ;
IF HeadProduction=NIL
THEN
HeadProduction := p
END ;
WITH p^ DO
next := NIL ;
statement := NIL ;
first := NIL ;
firstsolved := FALSE ;
followinfo := NewFollow() ;
line := GetCurrentLine() ;
description := NulName
END ;
RETURN( p )
END NewProduction ;
(*
NewFactor -
*)
PROCEDURE NewFactor () : FactorDesc ;
VAR
f: FactorDesc ;
BEGIN
NEW(f) ;
WITH f^ DO
next := NIL ;
followinfo := NewFollow() ;
line := GetCurrentLine()
END ;
RETURN( f )
END NewFactor ;
(*
NewTerm - returns a new term.
*)
PROCEDURE NewTerm () : TermDesc ;
VAR
t: TermDesc ;
BEGIN
NEW(t) ;
WITH t^ DO
factor := NIL ;
followinfo := NewFollow() ;
next := NIL ;
line := GetCurrentLine()
END ;
RETURN( t )
END NewTerm ;
(*
NewExpression - returns a new expression.
*)
PROCEDURE NewExpression () : ExpressionDesc ;
VAR
e: ExpressionDesc ;
BEGIN
NEW(e) ;
WITH e^ DO
term := NIL ;
followinfo := NewFollow() ;
line := GetCurrentLine()
END ;
RETURN( e )
END NewExpression ;
(*
NewStatement - returns a new statement.
*)
PROCEDURE NewStatement () : StatementDesc ;
VAR
s: StatementDesc ;
BEGIN
NEW(s) ;
WITH s^ DO
ident := NIL ;
expr := NIL ;
followinfo := NewFollow() ;
line := GetCurrentLine()
END ;
RETURN( s )
END NewStatement ;
(*
NewSetDesc - creates a new set description and returns the data structure.
*)
PROCEDURE NewSetDesc () : SetDesc ;
VAR
s: SetDesc ;
BEGIN
NEW(s) ;
WITH s^ DO
next := NIL
END ;
RETURN( s )
END NewSetDesc ;
(*
NewCodeDesc - creates a new code descriptor and initializes all fields to zero.
*)
PROCEDURE NewCodeDesc () : CodeDesc ;
VAR
c: CodeDesc ;
BEGIN
NEW(c) ;
WITH c^ DO
code := NIL ;
indent := 0 ;
line := GetCurrentLine()
END ;
RETURN( c )
END NewCodeDesc ;
(*
CodeFragmentPrologue - consumes code text up to a "%" after a newline.
*)
PROCEDURE CodeFragmentPrologue ;
BEGIN
LinePrologue := GetCurrentLine() ;
GetCodeFragment(CodePrologue)
END CodeFragmentPrologue ;
(*
CodeFragmentEpilogue - consumes code text up to a "%" after a newline.
*)
PROCEDURE CodeFragmentEpilogue ;
BEGIN
LineEpilogue := GetCurrentLine() ;
GetCodeFragment(CodeEpilogue)
END CodeFragmentEpilogue ;
(*
CodeFragmentDeclaration - consumes code text up to a "%" after a newline.
*)
PROCEDURE CodeFragmentDeclaration ;
BEGIN
LineDeclaration := GetCurrentLine() ;
GetCodeFragment(CodeDeclaration)
END CodeFragmentDeclaration ;
(*
GetCodeFragment - collects the code fragment up until ^ %
*)
PROCEDURE GetCodeFragment (VAR h: CodeHunk) ;
VAR
i : CARDINAL ;
ch: CHAR ;
BEGIN
h := NIL ;
i := 0 ;
WHILE (PutChar(GetChar())#'%') AND (PutChar(GetChar())#nul) DO
REPEAT
WHILE (PutChar(GetChar())#nul) AND (PutChar(GetChar())#lf) DO
h := Add(h, GetChar(), i)
END ;
IF PutChar(GetChar())=lf
THEN
(* consume line feed *)
h := Add(h, GetChar(), i) ;
ch := PutChar(lf)
ELSIF PutChar(GetChar())=nul
THEN
ch := PutChar(nul) ;
ch := PutChar(lf)
ELSE
ch := PutChar(PutChar(GetChar()))
END
UNTIL GetChar()=lf
END ;
IF PutChar(GetChar())='%'
THEN
h := Add(h, nul, i) ;
ch := PutChar(' ') ; (* to give the following token % a delimiter infront of it *)
AdvanceToken
ELSE
WarnError('expecting % to terminate code fragment, found end of file')
END
END GetCodeFragment ;
(*
WriteCodeHunkList - writes the CodeHunk list in the correct order.
*)
PROCEDURE WriteCodeHunkList (l: CodeHunk) ;
BEGIN
IF l#NIL
THEN
OnLineStart := FALSE ;
(* recursion *)
WITH l^ DO
WriteCodeHunkList(next) ;
Output.WriteString(codetext)
END
END
END WriteCodeHunkList ;
(*
WriteIndent - writes, n, spaces.
*)
PROCEDURE WriteIndent (n: CARDINAL) ;
BEGIN
WHILE n>0 DO
Output.Write(' ') ;
DEC(n)
END ;
OnLineStart := FALSE
END WriteIndent ;
(*
CheckWrite -
*)
PROCEDURE CheckWrite (ch: CHAR; VAR curpos: CARDINAL; left: CARDINAL; VAR seentext: BOOLEAN) ;
BEGIN
IF ch=lf
THEN
NewLine(left) ;
curpos := 0 ;
seentext := FALSE
ELSE
Output.Write(ch) ;
INC(curpos)
END
END CheckWrite ;
(*
WriteStringIndent - writes a string but it will try and remove upto indent spaces
if they exist.
*)
PROCEDURE WriteStringIndent (a: ARRAY OF CHAR; indent: CARDINAL;
VAR curpos: CARDINAL;
left: CARDINAL; VAR seentext: BOOLEAN) ;
VAR
l, i: CARDINAL ;
BEGIN
i := 0 ;
l := StrLen(a) ;
WHILE i<l DO
IF seentext
THEN
CheckWrite(a[i], curpos, left, seentext)
ELSE
IF a[i]=' '
THEN
(* ignore space for now *)
INC(curpos)
ELSE
IF curpos>=indent
THEN
WriteIndent(curpos-indent)
END ;
seentext := TRUE ;
CheckWrite(a[i], curpos, left, seentext)
END
END ;
INC(i)
END
END WriteStringIndent ;
(*
WriteCodeHunkListIndent - writes the CodeHunk list in the correct order
but it removes up to indent spaces if they exist.
*)
PROCEDURE WriteCodeHunkListIndent (l: CodeHunk; indent: CARDINAL;
VAR curpos: CARDINAL;
left: CARDINAL; VAR seentext: BOOLEAN) ;
BEGIN
IF l#NIL
THEN
(* recursion *)
WITH l^ DO
WriteCodeHunkListIndent(next, indent, curpos, left, seentext) ;
WriteStringIndent(codetext, indent, curpos, left, seentext)
END
END
END WriteCodeHunkListIndent ;
(*
Add - adds a character to a code hunk and creates another code hunk if necessary.
*)
PROCEDURE Add (VAR p: CodeHunk; ch: CHAR; VAR i: CARDINAL) : CodeHunk ;
VAR
q: CodeHunk ;
BEGIN
IF (p=NIL) OR (i>MaxCodeHunkLength)
THEN
NEW(q) ;
q^.next := p ;
q^.codetext[0] := ch ;
i := 1 ;
RETURN( q )
ELSE
p^.codetext[i] := ch ;
INC(i) ;
RETURN( p )
END
END Add ;
(*
ConsHunk - combine two possible code hunks.
*)
PROCEDURE ConsHunk (VAR p: CodeHunk; q: CodeHunk) ;
VAR
r: CodeHunk ;
BEGIN
IF p#NIL
THEN
r := q ;
WHILE r^.next#NIL DO
r := r^.next
END ;
r^.next := p ;
END ;
p := q
END ConsHunk ;
(*
GetName - returns the next symbol which is checked for a legal name.
*)
PROCEDURE GetName () : Name ;
VAR
name: Name ;
BEGIN
IF IsReserved(GetCurrentToken())
THEN
WarnError('expecting a name and found a reserved word') ;
AdvanceToken ; (* move on to another token *)
RETURN( NulName )
ELSE
name := GetCurrentToken() ;
AdvanceToken ;
RETURN( name )
END
END GetName ;
(* % rules *)
(*
Note that all the code from here down to the end of the module as
delimited by the comment will all be hidden when the buildpg
script is invoked. Also be careful not to duplicate or remove these
critical comments below..
Check buildpg for sed details.
*)
(* StartNonErrorChecking *)
(* actually these two are not strictly rules but hand built primitives *)
(*
Ident - non error checking varient of Ident
*)
PROCEDURE Ident () : BOOLEAN ;
BEGIN
IF GetCurrentTokenType()=identtok
THEN
NEW(CurrentIdent) ;
WITH CurrentIdent^ DO
definition := NIL ;
name := GetName() ;
line := GetCurrentLine()
END ;
RETURN( TRUE )
ELSE
RETURN( FALSE )
END
END Ident ;
(*
Modula2Code - non error checking varient of Modula2Code
*)
PROCEDURE Modula2Code () : BOOLEAN ;
VAR
p : CodeHunk ;
i : CARDINAL ;
quote : BOOLEAN ;
line,
position: CARDINAL ;
BEGIN
line := GetCurrentLine() ;
PushBackToken(GetCurrentToken()) ;
position := GetColumnPosition() ;
p := NIL ;
SkipWhite ;
WHILE (PutChar(GetChar())#'%') AND (PutChar(GetChar())#nul) DO
IF PutChar(GetChar())='"'
THEN
REPEAT
p := Add(p, GetChar(), i)
UNTIL (PutChar(GetChar())='"') OR (PutChar(GetChar())=nul) ;
p := Add(p, '"', i) ;
IF (PutChar(GetChar())='"') AND (GetChar()='"')
THEN
END
ELSIF PutChar(GetChar())="'"
THEN
REPEAT
p := Add(p, GetChar(), i)
UNTIL (PutChar(GetChar())="'") OR (PutChar(GetChar())=nul) ;
p := Add(p, "'", i) ;
IF (PutChar(GetChar())="'") AND (GetChar()="'")
THEN
END
ELSIF (PutChar(GetChar())='\') AND (GetChar()='\')
THEN
p := Add(p, GetChar(), i)
ELSIF PutChar(GetChar())#'%'
THEN
p := Add(p, GetChar(), i)
END
END ;
p := Add(p, nul, i) ;
WITH CurrentFactor^ DO
type := m2 ;
code := NewCodeDesc() ;
WITH code^ DO
code := p ;
indent := position
END
END ;
IF PutChar(' ')=' '
THEN
END ;
AdvanceToken ; (* read the next token ready for the parser *)
IF NOT WasNoError
THEN
WarnError1('error probably occurred before the start of inline code on line %d', line)
END ;
RETURN( TRUE )
END Modula2Code ;
(*
StartModName := % ModuleName := GetName() ; (* ignore begintok *) CodeFragmentPrologue % =:
*)
PROCEDURE StartModName () : BOOLEAN ;
BEGIN
ModuleName := GetName() ;
CodeFragmentPrologue ;
RETURN( TRUE )
END StartModName ;
(*
EndModName :=
*)
PROCEDURE EndModName () : BOOLEAN ;
BEGIN
IF ModuleName#GetName()
THEN
WarnError('expecting same module name at end as beginning')
END ;
(* ignore endtok as it consumes the token afterwards *)
CodeFragmentEpilogue ;
RETURN( TRUE )
END EndModName ;
(*
DoDeclaration := % CodeFragmentDeclaration % =:
*)
PROCEDURE DoDeclaration () : BOOLEAN ;
BEGIN
IF ModuleName#GetName()
THEN
WarnError('expecting same module name in declaration as in the beginning')
END ;
(* ignore begintok as it consumes the token afterwards *)
CodeFragmentDeclaration ;
RETURN( TRUE )
END DoDeclaration ;
(* EndNonErrorChecking now for the real ebnf rules *)
TYPE
SetOfStop = SET OF TokenType ;
(* **************************************************************************
E r r o r R e c o v e r y I d e n t & M o d u l a 2 C o d e
**************************************************************************
(* StartErrorChecking *)
(*
SyntaxError - after a syntax error we skip all tokens up until we reach
a stop symbol.
*)
PROCEDURE SyntaxError (stop: SetOfStop) ;
BEGIN
DescribeError ;
IF Debugging
THEN
WriteLn ;
WriteString('skipping token *** ')
END ;
WHILE NOT (GetCurrentTokenType() IN stop) DO
AdvanceToken
END ;
IF Debugging
THEN
WriteString(' ***') ; WriteLn
END ;
WasNoError := FALSE
END SyntaxError ;
(*
SyntaxCheck -
*)
PROCEDURE SyntaxCheck (stop: SetOfStop) ;
BEGIN
IF NOT (GetCurrentTokenType() IN stop)
THEN
SyntaxError(stop)
END
END SyntaxCheck ;
(*
Expect -
*)
PROCEDURE Expect (t: TokenType; stop: SetOfStop) ;
BEGIN
IF GetCurrentTokenType()=t
THEN
AdvanceToken
ELSE
SyntaxError(stop)
END ;
SyntaxCheck(stop)
END Expect ;
(*
Ident - error checking varient of Ident
*)
PROCEDURE Ident (stop: SetOfStop) ;
BEGIN
IF GetCurrentTokenType()=identtok
THEN
NEW(CurrentIdent) ;
WITH CurrentIdent^ DO
definition := NIL ;
name := GetName() ;
line := GetCurrentLine()
END ;
END
END Ident ;
(*
Modula2Code - error checking varient of Modula2Code
*)
PROCEDURE Modula2Code (stop: SetOfStop) ;
VAR
p : CodeHunk ;
i : CARDINAL ;
quote : BOOLEAN ;
line,
position: CARDINAL ;
BEGIN
line := GetCurrentLine() ;
PushBackToken(GetCurrentToken()) ;
position := GetColumnPosition() ;
p := NIL ;
SkipWhite ;
WHILE (PutChar(GetChar())#'%') AND (PutChar(GetChar())#nul) DO
IF PutChar(GetChar())='"'
THEN
REPEAT
p := Add(p, GetChar(), i)
UNTIL (PutChar(GetChar())='"') OR (PutChar(GetChar())=nul) ;
p := Add(p, '"', i) ;
IF (PutChar(GetChar())='"') AND (GetChar()='"')
THEN
END
ELSIF PutChar(GetChar())="'"
THEN
REPEAT
p := Add(p, GetChar(), i)
UNTIL (PutChar(GetChar())="'") OR (PutChar(GetChar())=nul) ;
p := Add(p, "'", i) ;
IF (PutChar(GetChar())="'") AND (GetChar()="'")
THEN
END
ELSIF (PutChar(GetChar())='\') AND (GetChar()='\')
THEN
p := Add(p, GetChar(), i)
ELSIF PutChar(GetChar())#'%'
THEN
p := Add(p, GetChar(), i)
END
END ;
p := Add(p, nul, i) ;
WITH CurrentFactor^ DO
type := m2 ;
code := NewCodeDesc() ;
WITH code^ DO
code := p ;
indent := position
END
END ;
IF PutChar(' ')=' '
THEN
END ;
AdvanceToken ; (* read the next token ready for the parser *)
IF NOT WasNoError
THEN
WarnError1('error probably occurred before the start of inline code on line %d', line)
END
END Modula2Code ;
(*
StartModName := % ModuleName := GetName() ; (* ignore begintok *) CodeFragmentPrologue % =:
*)
PROCEDURE StartModName (stop: SetOfStop) ;
BEGIN
ModuleName := GetName() ;
CodeFragmentPrologue
END StartModName ;
(*
EndModName :=
*)
PROCEDURE EndModName (stop: SetOfStop) ;
BEGIN
IF ModuleName#GetName()
THEN
WarnError('expecting same module name at end as beginning')
END ;
(* ignore endtok as it consumes the token afterwards *)
CodeFragmentEpilogue
END EndModName ;
(*
DoDeclaration := % CodeFragmentDeclaration % =:
*)
PROCEDURE DoDeclaration (stop: SetOfStop) ;
BEGIN
IF ModuleName#GetName()
THEN
WarnError('expecting same module name in declaration as in the beginning')
END ;
(* ignore begintok as it consumes the token afterwards *)
CodeFragmentDeclaration
END DoDeclaration ;
(* EndErrorChecking now for the real ebnf rules *)
*****************************************************************
l e a v e a b o v e c o d e a l o n e (f o r S E D)
***************************************************************** *)
(* this code below will be recreated by ppg *)
PROCEDURE DescribeError ;
BEGIN
WarnError('syntax error')
END DescribeError ;
PROCEDURE Main () : BOOLEAN ;
BEGIN
IF Header()
THEN
IF Decls()
THEN
IF Footer()
THEN
IF Rules()
THEN
RETURN( TRUE )
END
END
END
END ;
RETURN( FALSE )
END Main ;
PROCEDURE Header () : BOOLEAN ;
BEGIN
IF SymIs(codetok)
THEN
IF SymIs(moduletok)
THEN
ModuleName := GetName() ;
(* ignore the begintok as we are looking one symbol ahead and we dont want to move over MODULE *)
CodeFragmentPrologue ;
RETURN( TRUE )
ELSE
WarnError('expecting module')
END
END ;
RETURN( FALSE )
END Header ;
PROCEDURE Footer () : BOOLEAN ;
BEGIN
IF SymIs(codetok)
THEN
IF SymIs(moduletok)
THEN
IF ModuleName#GetName()
THEN
WarnError('expecting same module name at end as beginning')
END ;
(* ignore endtok as it consumes the token afterwards *)
CodeFragmentEpilogue ;
RETURN( TRUE )
ELSE
WarnError('expecting module')
END
END ;
RETURN( FALSE )
END Footer ;
PROCEDURE Decls () : BOOLEAN ;
BEGIN
IF SymIs(codetok)
THEN
IF SymIs(declarationtok)
THEN
RETURN( DoDeclaration() )
ELSE
WarnError('expecting declaration')
END
END ;
RETURN( FALSE )
END Decls ;
(*
Rules := " % " " rules " { Defs } ExtBNF =:
*)
PROCEDURE Rules () : BOOLEAN ;
BEGIN
IF SymIs(codetok)
THEN
IF SymIs(rulestok)
THEN
WHILE Defs() DO
END ;
IF ExtBNF()
THEN
RETURN( TRUE )
ELSE
WarnError('expecting some BNF rules to be present')
END
END
END ;
RETURN( FALSE )
END Rules ;
(*
Defs := " special " Special | " token " Token | " error " ErrorProcedures |
"tokenfunc" TokenProcedure =:
*)
PROCEDURE Defs () : BOOLEAN ;
BEGIN
IF SymIs(specialtok)
THEN
IF Special()
THEN
RETURN( TRUE )
END
ELSIF SymIs(tokentok)
THEN
IF Token()
THEN
RETURN( TRUE )
END
ELSIF SymIs(errortok)
THEN
IF ErrorProcedures()
THEN
RETURN( TRUE )
END
ELSIF SymIs(tfunctok)
THEN
IF TokenProcedure()
THEN
RETURN( TRUE )
END
ELSIF SymIs(symfunctok)
THEN
IF SymProcedure()
THEN
RETURN( TRUE )
END
END ;
RETURN( FALSE )
END Defs ;
(*
Special := Name First Follow [ "epsilon" ] =:
*)
PROCEDURE Special () : BOOLEAN ;
VAR
p: ProductionDesc ;
BEGIN
IF Ident()
THEN
p := NewProduction() ;
p^.statement := NewStatement() ;
p^.statement^.followinfo^.calcfollow := TRUE ;
p^.statement^.followinfo^.epsilon := false ;
p^.statement^.followinfo^.reachend := false ;
p^.statement^.ident := CurrentIdent ;
p^.statement^.expr := NIL ;
p^.firstsolved := TRUE ;
p^.followinfo^.calcfollow := TRUE ;
p^.followinfo^.epsilon := false ;
p^.followinfo^.reachend := false ;
IF First()
THEN
IF Follow()
THEN
IF SymIs(epsilontok)
THEN
p^.statement^.followinfo^.epsilon := true ; (* these are not used - but they are displayed when debugging *)
p^.statement^.followinfo^.reachend := true ;
p^.followinfo^.epsilon := true ;
p^.followinfo^.reachend := true
END ;
IF Literal()
THEN
p^.description := LastLiteral
END ;
RETURN( TRUE )
ELSE
WarnError('Follow - expected') ;
RETURN( FALSE )
END ;
ELSE
WarnError('First - expected') ;
RETURN( FALSE )
END
ELSE
RETURN( FALSE )
END
END Special ;
(*
First := 'first' '{' { LitOrTokenOrIdent % WITH LastSetDesc^ DO
next := HeadProduction^.first ;
END ;
TailProduction^.first := LastSetDesc ;
%
} '}'
*)
PROCEDURE First () : BOOLEAN ;
BEGIN
IF SymIs(firsttok)
THEN
IF SymIs(lcparatok)
THEN
WHILE LitOrTokenOrIdent() DO
WITH CurrentSetDesc^ DO
next := TailProduction^.first ;
END ;
TailProduction^.first := CurrentSetDesc
END ; (* while *)
IF SymIs(rcparatok)
THEN
RETURN( TRUE )
ELSE
WarnError("'}' - expected") ;
RETURN( FALSE )
END ;
ELSE
WarnError("'{' - expected") ;
RETURN( FALSE )
END ;
ELSE
RETURN( FALSE )
END ;
END First ;
(*
Follow := 'follow' '{' { LitOrTokenOrIdent } '}'
*)
PROCEDURE Follow () : BOOLEAN ;
BEGIN
IF SymIs(followtok)
THEN
IF SymIs(lcparatok)
THEN
WHILE LitOrTokenOrIdent() DO
WITH CurrentSetDesc^ DO
next := TailProduction^.followinfo^.follow ;
END ;
TailProduction^.followinfo^.follow := CurrentSetDesc
END ; (* while *)
IF SymIs(rcparatok)
THEN
RETURN( TRUE )
ELSE
WarnError("'}' - expected") ;
RETURN( FALSE )
END ;
ELSE
WarnError("'{' - expected") ;
RETURN( FALSE )
END ;
ELSE
RETURN( FALSE )
END ;
END Follow ;
(*
LitOrTokenOrIdent := Literal % CurrentSetDesc := NewSetDesc() ;
WITH CurrentSetDesc^ DO
type := litel ;
string := LastLiteral ;
END ;
%
| '<' % CurrentSetDesc := NewSetDesc() ;
WITH CurrentSetDesc^ DO
type := tokel ;
string := GetCurrentToken() ;
END ;
AdvanceToken() ;
%
'>' | Ident % CurrentSetDesc := NewSetDesc() ;
WITH CurrentSetDesc^ DO
type := idel ;
ident := CurrentIdent ;
END ;
%
*)
PROCEDURE LitOrTokenOrIdent () : BOOLEAN ;
BEGIN
IF Literal()
THEN
CurrentSetDesc := NewSetDesc() ;
WITH CurrentSetDesc^ DO
type := litel ;
string := LastLiteral
END ;
RETURN( TRUE )
ELSIF SymIs(lesstok)
THEN
CurrentSetDesc := NewSetDesc() ;
WITH CurrentSetDesc^ DO
type := tokel ;
string := GetCurrentToken() ;
END ;
IF GetSymKey(Aliases, GetCurrentToken())=NulKey
THEN
(*
PutSymKey(Values, GetCurrentToken(), LargestValue) ;
PutSymKey(Aliases, GetCurrentToken(), GetCurrentToken()) ;
PutSymKey(ReverseAliases, GetCurrentToken(), GetCurrentToken()) ;
INC(LargestValue) ;
*)
END ;
AdvanceToken() ;
IF SymIs(gretok)
THEN
RETURN( TRUE )
ELSE
WarnError("'>' - expected") ;
RETURN( FALSE )
END ;
ELSIF Ident()
THEN
CurrentSetDesc := NewSetDesc() ;
WITH CurrentSetDesc^ DO
type := idel ;
ident := CurrentIdent ;
END ;
RETURN( TRUE )
ELSE
RETURN( FALSE )
END ; (* elsif *)
END LitOrTokenOrIdent ;
(*
Literal -
*)
PROCEDURE Literal () : BOOLEAN ;
BEGIN
IF SymIs(squotetok)
THEN
LastLiteral := GetCurrentToken() ;
AdvanceToken ;
IF SymIs(squotetok)
THEN
RETURN( TRUE )
END
ELSIF SymIs(dquotetok)
THEN
LastLiteral := GetCurrentToken() ;
AdvanceToken ;
IF SymIs(dquotetok)
THEN
RETURN( TRUE )
END
END ;
RETURN( FALSE )
END Literal ;
(*
Token := Literal % VAR l: CARDINAL ;
l := GetCurrentToken() ; %
Name % PutSymKey(Aliases, l, GetCurrentToken()) ; % =:
*)
PROCEDURE Token () : BOOLEAN ;
BEGIN
IF Literal()
THEN
AddEntry(Aliases, LastLiteral, GetCurrentToken()) ;
AddEntry(ReverseAliases, GetCurrentToken(), LastLiteral) ;
AddEntry(Values, GetCurrentToken(), LargestValue) ;
AddEntry(ReverseValues, Name(LargestValue), GetCurrentToken()) ;
INC(LargestValue) ;
AdvanceToken ;
RETURN( TRUE )
ELSE
RETURN( FALSE )
END
END Token ;
(*
ErrorProcedures := Literal % ErrorProcArray := LastLiteral %
Literal % ErrorProcString := LastLiteral % =:
*)
PROCEDURE ErrorProcedures () : BOOLEAN ;
BEGIN
IF Literal()
THEN
ErrorProcArray := LastLiteral ;
IF Literal()
THEN
ErrorProcString := LastLiteral ;
RETURN( TRUE )
END
END ;
RETURN( FALSE )
END ErrorProcedures ;
(*
TokenProcedure := Literal % TokenTypeProc := LastLiteral % =:
*)
PROCEDURE TokenProcedure () : BOOLEAN ;
BEGIN
IF Literal()
THEN
TokenTypeProc := LastLiteral ;
RETURN( TRUE )
ELSE
RETURN( FALSE )
END
END TokenProcedure ;
(*
SymProcedure := Literal % SymIsProc := LastLiteral % =:
*)
PROCEDURE SymProcedure () : BOOLEAN ;
BEGIN
IF Literal()
THEN
SymIsProc := LastLiteral ;
RETURN( TRUE )
ELSE
RETURN( FALSE )
END
END SymProcedure ;
(*
ExtBNF := " BNF " { Production } " FNB " =:
*)
PROCEDURE ExtBNF () : BOOLEAN ;
BEGIN
IF SymIs(BNFtok)
THEN
WHILE Production() DO
END ;
IF SymIs(FNBtok)
THEN
RETURN( TRUE )
END
END ;
RETURN( FALSE )
END ExtBNF ;
(*
Production := Statement =:
*)
PROCEDURE Production () : BOOLEAN ;
BEGIN
IF Statement()
THEN
RETURN( TRUE )
END ;
RETURN( FALSE )
END Production ;
(*
Statement := % VAR i: IdentDesc ; %
Ident
% i := CurrentIdent ; %
" := "
% VAR e: ExpressionDesc ;
e := NewExpression() ; %
Expression
% WITH CurrentStatement^ DO
ident := i ;
expr := e ;
first := NIL ;
END ;
%
" =: " =:
*)
PROCEDURE Statement () : BOOLEAN ;
VAR
i: IdentDesc ;
s: StatementDesc ;
e: ExpressionDesc ;
p: ProductionDesc ;
BEGIN
IF Ident()
THEN
p := FindDefinition(CurrentIdent^.name) ;
IF p=NIL
THEN
p := NewProduction()
ELSE
IF NOT ((p^.statement=NIL) OR (p^.statement^.expr=NIL))
THEN
WarnError1('already declared rule %s', CurrentIdent^.name)
END
END ;
i := CurrentIdent ;
IF SymIs(lbecomestok)
THEN
e := NewExpression() ;
CurrentExpression := e ;
s := NewStatement() ;
WITH s^ DO
ident := i ;
expr := e ;
END ;
IF Expression()
THEN
p^.statement := s ;
IF SymIs(rbecomestok)
THEN
RETURN( TRUE )
END
END
END
END ;
RETURN( FALSE )
END Statement ;
(*
Expression := % CurrentTerm := NIL %
Term { " | " % CurrentTerm := NewTerm() % Term } =:
*)
PROCEDURE Expression () : BOOLEAN ;
VAR
t1, t2: TermDesc ;
e : ExpressionDesc ;
BEGIN
e := CurrentExpression ;
t1 := NewTerm() ;
CurrentTerm := t1 ;
IF Term()
THEN
e^.term := t1 ;
WHILE SymIs(bartok) DO
t2 := NewTerm() ;
CurrentTerm := t2 ;
IF Term()
THEN
t1^.next := t2 ;
t1 := t2
ELSE
WarnError('term expected')
END
END ;
RETURN( TRUE )
ELSE
(* DISPOSE(t1) ; *)
RETURN( FALSE )
END
END Expression ;
(*
Term := Factor { Factor } =:
*)
PROCEDURE Term () : BOOLEAN ;
VAR
t1: TermDesc ;
f1, f2: FactorDesc ;
BEGIN
CurrentFactor := NewFactor() ;
f1 := CurrentFactor ;
t1 := CurrentTerm ;
IF Factor()
THEN
t1^.factor := f1 ;
f2 := NewFactor() ;
CurrentFactor := f2 ;
WHILE Factor() DO
f1^.next := f2 ;
f1 := f2 ;
f2 := NewFactor() ;
CurrentFactor := f2 ;
END ;
(* DISPOSE(f2) ; *)
RETURN( TRUE )
ELSE
(* DISPOSE(f1) ; *)
RETURN( FALSE )
END
END Term ;
(*
Factor := " % " Modula2Code " % " % AssignCode ; % |
( Ident | Literal | " { " Expression " } " |
" [ " Expression " ] " | " ( " Expression " ) " ) =:
*)
PROCEDURE Factor () : BOOLEAN ;
BEGIN
IF SymIs(codetok)
THEN
IF Modula2Code()
THEN
IF SymIs(codetok)
THEN
RETURN( TRUE )
END
END
ELSE
IF Ident()
THEN
WITH CurrentFactor^ DO
type := id ;
ident := CurrentIdent
END ;
RETURN( TRUE )
ELSIF Literal()
THEN
WITH CurrentFactor^ DO
type := lit ;
string := LastLiteral ;
IF GetSymKey(Aliases, LastLiteral)=NulKey
THEN
WarnError1('no token defined for literal %s', LastLiteral)
END
END ;
RETURN( TRUE )
ELSIF SymIs(lcparatok)
THEN
WITH CurrentFactor^ DO
type := mult ;
expr := NewExpression() ;
CurrentExpression := expr ;
IF Expression()
THEN
IF SymIs(rcparatok)
THEN
RETURN( TRUE )
ELSE
WarnError('} expected')
END
END
END
ELSIF SymIs(lsparatok)
THEN
WITH CurrentFactor^ DO
type := opt ;
expr := NewExpression() ;
CurrentExpression := expr ;
IF Expression()
THEN
IF SymIs(rsparatok)
THEN
RETURN( TRUE )
ELSE
WarnError('] expected')
END
END
END
ELSIF SymIs(lparatok)
THEN
WITH CurrentFactor^ DO
type := sub ;
expr := NewExpression() ;
CurrentExpression := expr ;
IF Expression()
THEN
IF SymIs(rparatok)
THEN
RETURN( TRUE )
ELSE
WarnError(') expected')
END
END
END
END
END ;
RETURN( FALSE )
END Factor ;
(* % module pg end *)
(*
GetDefinitionName - returns the name of the rule inside, p.
*)
PROCEDURE GetDefinitionName (p: ProductionDesc) : Name ;
BEGIN
IF p#NIL
THEN
WITH p^ DO
IF (statement#NIL) AND (statement^.ident#NIL)
THEN
RETURN( statement^.ident^.name )
END
END
END ;
RETURN( NulName )
END GetDefinitionName ;
(*
FindDefinition - searches and returns the rule which defines, n.
*)
PROCEDURE FindDefinition (n: Name) : ProductionDesc ;
VAR
p, f: ProductionDesc ;
BEGIN
p := HeadProduction ;
f := NIL ;
WHILE p#NIL DO
IF GetDefinitionName(p)=n
THEN
IF f=NIL
THEN
f := p
ELSE
WriteString('multiple definition for rule: ') ; WriteKey(n) ; WriteLn
END
END ;
p := p^.next
END ;
RETURN( f )
END FindDefinition ;
(*
BackPatchIdent - found an ident, i, we must look for the corresponding rule and
set the definition accordingly.
*)
PROCEDURE BackPatchIdent (i: IdentDesc) ;
BEGIN
IF i#NIL
THEN
WITH i^ DO
definition := FindDefinition(name) ;
IF definition=NIL
THEN
WarnError1('unable to find production %s', name) ;
WasNoError := FALSE
END
END
END
END BackPatchIdent ;
(*
BackPatchFactor - runs through the factor looking for an ident
*)
PROCEDURE BackPatchFactor (f: FactorDesc) ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : BackPatchIdent(ident) |
sub ,
opt ,
mult: BackPatchExpression(expr)
ELSE
END
END ;
f := f^.next
END
END BackPatchFactor ;
(*
BackPatchTerm - runs through all terms to find idents.
*)
PROCEDURE BackPatchTerm (t: TermDesc) ;
BEGIN
WHILE t#NIL DO
BackPatchFactor(t^.factor) ;
t := t^.next
END
END BackPatchTerm ;
(*
BackPatchExpression - runs through the term to find any idents.
*)
PROCEDURE BackPatchExpression (e: ExpressionDesc) ;
BEGIN
IF e#NIL
THEN
BackPatchTerm(e^.term)
END
END BackPatchExpression ;
(*
BackPatchSet -
*)
PROCEDURE BackPatchSet (s: SetDesc) ;
BEGIN
WHILE s#NIL DO
WITH s^ DO
CASE type OF
idel: BackPatchIdent(ident)
ELSE
END
END ;
s := s^.next
END
END BackPatchSet ;
(*
BackPatchIdentToDefinitions - search through all the rules and add a link from any ident
to the definition.
*)
PROCEDURE BackPatchIdentToDefinitions (d: ProductionDesc) ;
BEGIN
IF (d#NIL) AND (d^.statement#NIL)
THEN
BackPatchExpression(d^.statement^.expr)
END
END BackPatchIdentToDefinitions ;
(*
CalculateFirstAndFollow -
*)
PROCEDURE CalculateFirstAndFollow (p: ProductionDesc) ;
BEGIN
IF Debugging
THEN
WriteLn ;
WriteKey(p^.statement^.ident^.name) ; WriteLn ;
WriteString(' calculating first')
END ;
CalcFirstProduction(p, p, p^.first) ;
BackPatchSet(p^.first) ;
IF Debugging
THEN
WriteString(' calculating follow set')
END ;
IF p^.followinfo^.follow=NIL
THEN
CalcFollowProduction(p)
END ;
BackPatchSet(p^.followinfo^.follow)
END CalculateFirstAndFollow ;
(*
ForeachRuleDo -
*)
PROCEDURE ForeachRuleDo (p: DoProcedure) ;
BEGIN
CurrentProduction := HeadProduction ;
WHILE CurrentProduction#NIL DO
p(CurrentProduction) ;
CurrentProduction := CurrentProduction^.next
END
END ForeachRuleDo ;
(*
WhileNotCompleteDo -
*)
PROCEDURE WhileNotCompleteDo (p: DoProcedure) ;
BEGIN
REPEAT
Finished := TRUE ;
ForeachRuleDo(p) ;
UNTIL Finished
END WhileNotCompleteDo ;
(*
NewLine - generate a newline and indent.
*)
PROCEDURE NewLine (Left: CARDINAL) ;
BEGIN
Output.WriteLn ;
BeginningOfLine := TRUE ;
Indent := 0 ;
WHILE Indent<Left DO
Output.Write(' ') ;
INC(Indent)
END
END NewLine ;
(*
CheckNewLine -
*)
PROCEDURE CheckNewLine (Left: CARDINAL) ;
BEGIN
IF Indent=Left
THEN
Left := BaseNewLine
END ;
IF Indent>BaseRightMargin
THEN
NewLine(Left)
END
END CheckNewLine ;
(*
IndentString - writes out a string with a preceeding indent.
*)
PROCEDURE IndentString (a: ARRAY OF CHAR) ;
VAR
i: CARDINAL ;
BEGIN
i := 0 ;
WHILE i<Indent DO
Output.Write(' ') ;
INC(i)
END ;
Output.WriteString(a) ;
LastLineNo := 0
END IndentString ;
(*
KeyWord - writes out a keywork with optional formatting directives.
*)
PROCEDURE KeyWord (n: Name) ;
BEGIN
IF KeywordFormatting
THEN
Output.WriteString('{%K') ;
IF (n = MakeKey('}')) OR (n = MakeKey('{')) OR (n = MakeKey('%'))
THEN
Output.Write('%') (* escape }, { or % *)
END ;
Output.WriteKey(n) ;
Output.Write('}')
ELSE
Output.WriteKey(n)
END
END KeyWord ;
(*
PrettyPara -
*)
PROCEDURE PrettyPara (c1, c2: ARRAY OF CHAR; e: ExpressionDesc; Left: CARDINAL) ;
BEGIN
Output.WriteString(c1) ;
INC(Indent, StrLen(c1)) ;
Left := Indent ;
PrettyCommentExpression(e, Left) ;
Output.WriteString(c2) ;
INC(Indent, StrLen(c2))
END PrettyPara ;
(*
WriteKeyTexinfo -
*)
PROCEDURE WriteKeyTexinfo (s: Name) ;
VAR
ds : String ;
ch : CHAR ;
i, l: CARDINAL ;
BEGIN
IF Texinfo
THEN
ds := InitStringCharStar(KeyToCharStar(s)) ;
l := Length(ds) ;
i := 0 ;
WHILE i<l DO
ch := char(ds, i) ;
IF (ch='{') OR (ch='}')
THEN
Output.Write('@')
END ;
Output.Write(ch) ;
INC(i)
END
ELSE
Output.WriteKey(s)
END
END WriteKeyTexinfo ;
(*
PrettyCommentFactor -
*)
PROCEDURE PrettyCommentFactor (f: FactorDesc; Left: CARDINAL) ;
VAR
curpos : CARDINAL ;
seentext: BOOLEAN ;
BEGIN
WHILE f#NIL DO
CheckNewLine(Left) ;
WITH f^ DO
CASE type OF
id : Output.WriteKey(ident^.name) ; Output.WriteString(' ') ;
INC(Indent, LengthKey(ident^.name)+1) |
lit : IF MakeKey("'")=string
THEN
Output.Write('"') ; WriteKeyTexinfo(string) ; Output.WriteString('" ')
ELSE
Output.Write("'") ; WriteKeyTexinfo(string) ; Output.WriteString("' ")
END ;
INC(Indent, LengthKey(string)+3) |
sub: PrettyPara('( ', ' ) ', expr, Left) |
opt: PrettyPara('[ ', ' ] ', expr, Left) |
mult: IF Texinfo
THEN
PrettyPara('@{ ', ' @} ', expr, Left)
ELSE
PrettyPara('{ ', ' } ', expr, Left)
END |
m2 : IF EmitCode
THEN
NewLine(Left) ; Output.WriteString('% ') ;
seentext := FALSE ;
curpos := 0 ;
WriteCodeHunkListIndent(code^.code, code^.indent, curpos, Left+2, seentext) ;
Output.WriteString(' %') ;
NewLine(Left)
END
ELSE
END ;
PrettyFollow('<f:', ':f>', followinfo)
END ;
f := f^.next
END
END PrettyCommentFactor ;
(*
PeepTerm - returns the length of characters in term.
*)
PROCEDURE PeepTerm (t: TermDesc) : CARDINAL ;
VAR
l: CARDINAL ;
BEGIN
l := 0 ;
WHILE t#NIL DO
INC(l, PeepFactor(t^.factor)) ;
IF t^.next#NIL
THEN
INC(l, 3)
END ;
t := t^.next
END ;
RETURN( l )
END PeepTerm ;
(*
PeepExpression - returns the length of the expression.
*)
PROCEDURE PeepExpression (e: ExpressionDesc) : CARDINAL ;
BEGIN
IF e=NIL
THEN
RETURN( 0 )
ELSE
RETURN( PeepTerm(e^.term) )
END
END PeepExpression ;
(*
PeepFactor - returns the length of character in the factor
*)
PROCEDURE PeepFactor (f: FactorDesc) : CARDINAL ;
VAR
l: CARDINAL ;
BEGIN
l := 0 ;
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : INC(l, LengthKey(ident^.name)+1) |
lit : INC(l, LengthKey(string)+3) |
opt ,
mult,
sub : INC(l, PeepExpression(expr)) |
m2 : (* empty *)
ELSE
END
END ;
f := f^.next
END ;
RETURN( l )
END PeepFactor ;
(*
PrettyCommentTerm -
*)
PROCEDURE PrettyCommentTerm (t: TermDesc; Left: CARDINAL) ;
BEGIN
WHILE t#NIL DO
CheckNewLine(Left) ;
PrettyCommentFactor(t^.factor, Left) ;
IF t^.next#NIL
THEN
Output.WriteString(' | ') ;
INC(Indent, 3) ;
IF PeepFactor(t^.factor)+Indent>BaseRightMargin
THEN
NewLine(Left)
END
END ;
PrettyFollow('<t:', ':t>', t^.followinfo) ;
t := t^.next
END
END PrettyCommentTerm ;
(*
PrettyCommentExpression -
*)
PROCEDURE PrettyCommentExpression (e: ExpressionDesc; Left: CARDINAL) ;
BEGIN
IF e#NIL
THEN
PrettyCommentTerm(e^.term, Left) ;
PrettyFollow('<e:', ':e>', e^.followinfo)
END
END PrettyCommentExpression ;
(*
PrettyCommentStatement -
*)
PROCEDURE PrettyCommentStatement (s: StatementDesc; Left: CARDINAL) ;
BEGIN
IF s#NIL
THEN
PrettyCommentExpression(s^.expr, Left) ;
PrettyFollow('<s:', ':s>', s^.followinfo)
END
END PrettyCommentStatement ;
(*
PrettyCommentProduction - generates the comment for rule, p.
*)
PROCEDURE PrettyCommentProduction (p: ProductionDesc) ;
VAR
to: SetDesc ;
BEGIN
IF p#NIL
THEN
BeginningOfLine := TRUE ;
Indent := 0 ;
Output.WriteString('(*') ; NewLine(3) ;
Output.WriteKey(GetDefinitionName(p)) ;
Output.WriteString(' := ') ;
INC(Indent, LengthKey(GetDefinitionName(p))+4) ;
PrettyCommentStatement(p^.statement, Indent) ;
NewLine(0) ;
IF ErrorRecovery
THEN
NewLine(3) ;
Output.WriteString('first symbols:') ;
EmitSet(p^.first, 0, 0) ;
NewLine(3) ;
PrettyFollow('<p:', ':p>', p^.followinfo) ;
NewLine(3) ;
CASE GetReachEnd(p^.followinfo) OF
true : Output.WriteString('reachend') |
false : Output.WriteString('cannot reachend') |
unknown: Output.WriteString('unknown...')
ELSE
END ;
NewLine(0)
END ;
Output.WriteString('*)') ; NewLine(0) ;
END
END PrettyCommentProduction ;
(*
PrettyPrintProduction - pretty prints the ebnf rule, p.
*)
PROCEDURE PrettyPrintProduction (p: ProductionDesc) ;
VAR
to: SetDesc ;
BEGIN
IF p#NIL
THEN
BeginningOfLine := TRUE ;
Indent := 0 ;
IF Texinfo
THEN
Output.WriteString('@example') ; NewLine(0)
ELSIF Sphinx
THEN
Output.WriteString('.. code-block:: ebnf') ; NewLine(0)
END ;
Output.WriteKey(GetDefinitionName(p)) ;
Output.WriteString(' := ') ;
INC(Indent, LengthKey(GetDefinitionName(p))+4) ;
PrettyCommentStatement(p^.statement, Indent) ;
IF p^.description#NulName
THEN
Output.WriteKey(p^.description)
END ;
NewLine(0) ;
WriteIndent(LengthKey(GetDefinitionName(p))+1) ;
Output.WriteString(' =: ') ;
NewLine(0) ;
IF Texinfo
THEN
Output.WriteString('@findex ') ; Output.WriteKey(GetDefinitionName(p)) ; Output.WriteString(' (ebnf)') ; NewLine(0) ;
Output.WriteString('@end example') ; NewLine(0)
ELSIF Sphinx
THEN
Output.WriteString('.. index::') ; NewLine(0) ;
Output.WriteString(' pair: ') ; Output.WriteKey(GetDefinitionName(p)) ; Output.WriteString('; (ebnf)') ; NewLine(0)
END ;
NewLine(0)
END
END PrettyPrintProduction ;
(*
EmitFileLineTag - emits a line and file tag using the C preprocessor syntax.
*)
PROCEDURE EmitFileLineTag (line: CARDINAL) ;
BEGIN
IF (NOT SuppressFileLineTag) AND (line#LastLineNo)
THEN
LastLineNo := line ;
IF NOT OnLineStart
THEN
Output.WriteLn
END ;
Output.WriteString('# ') ; Output.WriteCard(line, 0) ; Output.WriteString(' "') ; Output.WriteString(FileName) ; Output.Write('"') ;
Output.WriteLn ;
OnLineStart := TRUE
END
END EmitFileLineTag ;
(*
EmitRule - generates a comment and code for rule, p.
*)
PROCEDURE EmitRule (p: ProductionDesc) ;
BEGIN
IF PrettyPrint
THEN
PrettyPrintProduction(p)
ELSE
PrettyCommentProduction(p) ;
IF ErrorRecovery
THEN
RecoverProduction(p)
ELSE
CodeProduction(p)
END
END
END EmitRule ;
(*
CodeCondition -
*)
PROCEDURE CodeCondition (m: m2condition) ;
BEGIN
CASE m OF
m2if,
m2none : IndentString('IF ') |
m2elsif: IndentString('ELSIF ') |
m2while: IndentString('WHILE ')
ELSE
Halt('unrecognised m2condition',
__FILE__, __FUNCTION__, __LINE__)
END
END CodeCondition ;
(*
CodeThenDo - codes a "THEN" or "DO" depending upon, m.
*)
PROCEDURE CodeThenDo (m: m2condition) ;
BEGIN
CASE m OF
m2if,
m2none,
m2elsif: IF LastLineNo=0
THEN
Output.WriteLn
END ;
IndentString('THEN') ;
Output.WriteLn |
m2while: Output.WriteString(' DO') ;
Output.WriteLn
ELSE
Halt('unrecognised m2condition',
__FILE__, __FUNCTION__, __LINE__)
END ;
OnLineStart := TRUE
END CodeThenDo ;
(*
CodeElseEnd - builds an ELSE END statement using string, end.
*)
PROCEDURE CodeElseEnd (end: ARRAY OF CHAR; consumed: BOOLEAN; f: FactorDesc; inopt: BOOLEAN) ;
BEGIN
Output.WriteLn ;
OnLineStart := TRUE ;
EmitFileLineTag(f^.line) ;
IF NOT inopt
THEN
IndentString('ELSE') ; WriteLn ;
INC(Indent, 3) ;
IF consumed
THEN
IndentString('') ;
Output.WriteKey(ErrorProcArray) ;
Output.Write('(') ;
WITH f^ DO
CASE type OF
id : Output.Write("'") ; Output.WriteKey(ident^.name) ; Output.WriteString(' - expected') ; Output.WriteString("') ;") |
lit : IF MakeKey("'")=string
THEN
Output.Write('"') ;
KeyWord(string) ;
Output.WriteString(' - expected') ; Output.WriteString('") ;')
ELSIF MakeKey('"')=string
THEN
Output.Write("'") ; KeyWord(string) ;
Output.WriteString(' - expected') ; Output.WriteString("') ;")
ELSE
Output.Write('"') ; Output.Write("'") ; KeyWord(string) ; Output.WriteString("' - expected") ;
Output.WriteString('") ;')
END
ELSE
END
END ;
Output.WriteLn
END ;
IndentString('RETURN( FALSE )') ;
DEC(Indent, 3) ;
Output.WriteLn
END ;
IndentString(end) ;
Output.WriteLn ;
OnLineStart := TRUE
END CodeElseEnd ;
(*
CodeEnd - codes a "END" depending upon, m.
*)
PROCEDURE CodeEnd (m: m2condition; t: TermDesc; consumed: BOOLEAN; f: FactorDesc; inopt: BOOLEAN) ;
BEGIN
DEC(Indent, 3) ;
Output.WriteLn ;
OnLineStart := TRUE ;
CASE m OF
m2none : IF t=NIL
THEN
CodeElseEnd('END ;', consumed, f, inopt)
END |
m2if : IF t=NIL
THEN
CodeElseEnd('END ; (* if *)', consumed, f, inopt)
END |
m2elsif: IF t=NIL
THEN
CodeElseEnd('END ; (* elsif *)', consumed, f, inopt)
END |
m2while: IndentString('END ; (* while *)')
ELSE
Halt('unrecognised m2condition',
__FILE__, __FUNCTION__, __LINE__)
END ;
OnLineStart := FALSE
END CodeEnd ;
(*
EmitNonVarCode - writes out, code, providing it is not a variable declaration.
*)
PROCEDURE EmitNonVarCode (code: CodeDesc; curpos, left: CARDINAL) ;
VAR
i : CARDINAL ;
t : CodeHunk ;
seentext: BOOLEAN ;
BEGIN
t := code^.code ;
IF (NOT FindStr(t, i, 'VAR')) AND EmitCode
THEN
seentext := FALSE ;
curpos := 0 ;
EmitFileLineTag(code^.line) ;
IndentString('') ;
WriteCodeHunkListIndent(code^.code, code^.indent, curpos, left, seentext) ;
Output.WriteString(' ;') ;
Output.WriteLn ;
OnLineStart := TRUE
END
END EmitNonVarCode ;
(*
ChainOn -
*)
PROCEDURE ChainOn (codeStack, f: FactorDesc) : FactorDesc ;
VAR
s: FactorDesc ;
BEGIN
f^.pushed := NIL ;
IF codeStack=NIL
THEN
RETURN( f )
ELSE
s := codeStack ;
WHILE s^.pushed#NIL DO
s := s^.pushed
END ;
s^.pushed := f ;
RETURN( codeStack )
END
END ChainOn ;
(*
FlushCode -
*)
PROCEDURE FlushCode (VAR codeStack: FactorDesc) ;
BEGIN
IF codeStack#NIL
THEN
NewLine(Indent) ; Output.WriteString('(* begin flushing code *)') ;
OnLineStart := FALSE ;
WHILE codeStack#NIL DO
NewLine(Indent) ; EmitNonVarCode(codeStack^.code, 0, Indent) ; NewLine(Indent) ;
codeStack := codeStack^.pushed ;
IF codeStack#NIL
THEN
Output.WriteString(' (* again flushing code *)') ; Output.WriteLn ;
OnLineStart := TRUE
END
END ;
NewLine(Indent) ;
Output.WriteString('(* end flushing code *)') ;
OnLineStart := FALSE
END
END FlushCode ;
(*
CodeFactor -
*)
PROCEDURE CodeFactor (f: FactorDesc; t: TermDesc; l, n: m2condition; inopt, inwhile, consumed: BOOLEAN; codeStack: FactorDesc) ;
BEGIN
IF f=NIL
THEN
IF (* ((l=m2elsif) OR (l=m2if) OR (l=m2none)) AND *) (NOT inwhile) AND (NOT inopt)
THEN
Output.WriteLn ;
IndentString('RETURN( TRUE )') ;
OnLineStart := FALSE
END
ELSE
WITH f^ DO
EmitFileLineTag(line) ;
CASE type OF
id : FlushCode(codeStack) ;
CodeCondition(n) ;
Output.WriteKey(ident^.name) ; Output.WriteString('()') ;
CodeThenDo(n) ;
INC(Indent, 3) ;
CodeFactor(f^.next, NIL, n, m2none, inopt, inwhile, TRUE, NIL) ;
CodeEnd(n, t, consumed, f, inopt) |
lit : FlushCode(codeStack) ;
CodeCondition(n) ;
Output.WriteKey(SymIsProc) ; Output.Write('(') ;
Output.WriteKey(GetSymKey(Aliases, string)) ; Output.Write(')') ;
CodeThenDo(n) ;
INC(Indent, 3) ;
CodeFactor(f^.next, NIL, n, m2none, inopt, inwhile, TRUE, NIL) ;
CodeEnd(n, t, consumed, f, inopt) |
sub: FlushCode(codeStack) ;
CodeExpression(expr, m2none, inopt, inwhile, consumed, NIL) ;
IF f^.next#NIL
THEN
(*
* the test above makes sure that we don't emit a RETURN( TRUE )
* after a subexpression. Remember sub expressions are not conditional
*)
CodeFactor(f^.next, t, n, m2none, inopt, inwhile, TRUE, NIL)
END |
opt: FlushCode(codeStack) ;
CodeExpression(expr, m2if, TRUE, inwhile, FALSE, NIL) ;
CodeFactor(f^.next, t, n, m2none, inopt, inwhile, consumed, NIL) |
mult: FlushCode(codeStack) ;
CodeExpression(expr, m2while, FALSE, TRUE, consumed, NIL) ;
CodeFactor(f^.next, t, n, m2none, inopt, inwhile, consumed, NIL) |
m2 : codeStack := ChainOn(codeStack, f) ;
IF consumed OR (f^.next=NIL)
THEN
FlushCode(codeStack)
END ;
CodeFactor(f^.next, t, n, m2none, inopt, inwhile, consumed, codeStack)
ELSE
END
END
END
END CodeFactor ;
(*
CodeTerm -
*)
PROCEDURE CodeTerm (t: TermDesc; m: m2condition; inopt, inwhile, consumed: BOOLEAN; codeStack: FactorDesc) ;
VAR
l: m2condition ;
BEGIN
l := m ;
WHILE t#NIL DO
EmitFileLineTag(t^.line) ;
IF (t^.factor^.type=m2) AND (m=m2elsif)
THEN
m := m2if ;
IndentString('ELSE') ; Output.WriteLn ;
OnLineStart := TRUE ;
INC(Indent, 3) ;
CodeFactor(t^.factor, t^.next, m2none, m2none, inopt, inwhile, consumed, codeStack) ;
DEC(Indent, 3) ;
IndentString('END ;') ; Output.WriteLn ;
OnLineStart := TRUE
ELSE
CodeFactor(t^.factor, t^.next, m2none, m, inopt, inwhile, consumed, codeStack)
END ;
l := m ;
IF t^.next#NIL
THEN
m := m2elsif
END ;
t := t^.next
END
END CodeTerm ;
(*
CodeExpression -
*)
PROCEDURE CodeExpression (e: ExpressionDesc; m: m2condition; inopt, inwhile, consumed: BOOLEAN; codeStack: FactorDesc) ;
BEGIN
IF e#NIL
THEN
EmitFileLineTag(e^.line) ;
CodeTerm(e^.term, m, inopt, inwhile, consumed, codeStack)
END
END CodeExpression ;
(*
CodeStatement -
*)
PROCEDURE CodeStatement (s: StatementDesc; m: m2condition) ;
BEGIN
IF s#NIL
THEN
EmitFileLineTag(s^.line) ;
CodeExpression(s^.expr, m, FALSE, FALSE, FALSE, NIL)
END
END CodeStatement ;
(*
CodeProduction - only encode grammer rules which are not special.
*)
PROCEDURE CodeProduction (p: ProductionDesc) ;
BEGIN
IF (p#NIL) AND ((NOT p^.firstsolved) OR ((p^.statement#NIL) AND (p^.statement^.expr#NIL)))
THEN
BeginningOfLine := TRUE ;
Indent := 0 ;
Output.WriteLn ;
EmitFileLineTag(p^.line) ;
IndentString('PROCEDURE ') ;
Output.WriteKey(GetDefinitionName(p)) ;
Output.WriteString(' () : BOOLEAN ;') ;
VarProduction(p) ;
Output.WriteLn ;
OnLineStart := TRUE ;
EmitFileLineTag(p^.line) ;
IndentString('BEGIN') ; WriteLn ;
OnLineStart := FALSE ;
EmitFileLineTag(p^.line) ;
Indent := 3 ;
CodeStatement(p^.statement, m2none) ;
Output.WriteLn ;
Indent := 0 ;
IndentString('END ') ; WriteKey(GetDefinitionName(p)) ; Output.WriteString(' ;') ;
Output.WriteLn ;
Output.WriteLn ;
Output.WriteLn
END
END CodeProduction ;
(* and now for the production of code which will recover from syntax errors *)
(*
RecoverCondition -
*)
PROCEDURE RecoverCondition (m: m2condition) ;
BEGIN
CASE m OF
m2if : IndentString('IF ') |
m2none : IndentString('IF ') |
m2elsif: IndentString('ELSIF ') |
m2while: IndentString('WHILE ')
ELSE
Halt('unrecognised m2condition',
__FILE__, __FUNCTION__, __LINE__)
END
END RecoverCondition ;
(*
ConditionIndent - returns the number of spaces indentation created via, m.
*)
PROCEDURE ConditionIndent (m: m2condition) : CARDINAL ;
BEGIN
CASE m OF
m2if : RETURN( 3 ) |
m2none : RETURN( 3 ) |
m2elsif: RETURN( 6 ) |
m2while: RETURN( 6 )
ELSE
Halt('unrecognised m2condition',
__FILE__, __FUNCTION__, __LINE__)
END
END ConditionIndent ;
(*
WriteGetTokenType - writes out the method of determining the token type.
*)
PROCEDURE WriteGetTokenType ;
BEGIN
Output.WriteKey(TokenTypeProc)
END WriteGetTokenType ;
(*
NumberOfElements - returns the number of elements in set, to, which lie between low..high
*)
PROCEDURE NumberOfElements (to: SetDesc; low, high: WORD) : CARDINAL ;
VAR
n: CARDINAL ;
BEGIN
n := 0 ;
WHILE to#NIL DO
WITH to^ DO
CASE type OF
tokel: IF (high=0) OR IsBetween(string, low, high)
THEN
INC(n)
END |
litel: IF (high=0) OR IsBetween(GetSymKey(Aliases, string), low, high)
THEN
INC(n)
END |
idel : WarnError('not expecting ident in first symbol list') ;
WasNoError := FALSE
ELSE
WarnError('unknown enuneration element') ;
WasNoError := FALSE
END
END ;
to := to^.next ;
END ;
RETURN( n )
END NumberOfElements ;
(*
WriteElement - writes the literal name for element, e.
*)
PROCEDURE WriteElement (e: WORD) ;
BEGIN
Output.WriteKey(GetSymKey(ReverseValues, e))
END WriteElement ;
(*
EmitIsInSet - writes out the equivalent of GetTokenType() IN { toset }
*)
PROCEDURE EmitIsInSet (to: SetDesc; low, high: Name) ;
BEGIN
IF NumberOfElements(to, low, high)=1
THEN
WriteGetTokenType ; Output.Write('=') ; EmitSet(to, low, high)
ELSE
WriteGetTokenType ;
Output.WriteString(' IN SetOfStop') ;
IF LargestValue > MaxElementsInSet
THEN
Output.WriteCard(CARDINAL(low) DIV MaxElementsInSet, 0)
END ;
Output.WriteString(' {') ; EmitSet(to, low, high) ; Output.WriteString('}')
END
END EmitIsInSet ;
(*
EmitIsInSubSet - writes out a test to see whether GetTokenype() is in { subset }
*)
PROCEDURE EmitIsInSubSet (to: SetDesc; low, high: WORD) ;
BEGIN
IF NumberOfElements(to, low, high)=1
THEN
Output.Write('(') ; EmitIsInSet(to, low, high) ; Output.Write(')')
ELSIF low=0
THEN
(* no need to check whether GetTokenType > low *)
Output.WriteString('((') ; WriteGetTokenType ; Output.Write('<') ; WriteElement(INTEGER(high)+1) ;
Output.WriteString(') AND (') ; EmitIsInSet(to, low, high) ; Output.WriteString('))')
ELSIF CARDINAL(high)>LargestValue
THEN
(* no need to check whether GetTokenType < high *)
Output.WriteString('((') ; WriteGetTokenType ; Output.WriteString('>=') ; WriteElement(low) ;
Output.WriteString(') AND (') ; EmitIsInSet(to, low, high) ; Output.WriteString('))')
ELSE
Output.WriteString('((') ; WriteGetTokenType ; Output.WriteString('>=') ; WriteElement(low) ;
Output.WriteString(') AND (') ; WriteGetTokenType ; Output.Write('<') ; WriteElement(INTEGER(high)+1) ;
Output.WriteString(') AND (') ; EmitIsInSet(to, low, high) ;
Output.WriteString('))')
END
END EmitIsInSubSet ;
(*
EmitIsInFirst -
*)
PROCEDURE EmitIsInFirst (to: SetDesc; m: m2condition) ;
VAR
i : CARDINAL ;
first: BOOLEAN ;
BEGIN
IF NumberOfElements(to, 0, 0)=1
THEN
(* only one element *)
WriteGetTokenType ;
Output.Write('=') ;
EmitSet(to, 0, 0)
ELSE
IF LargestValue<=MaxElementsInSet
THEN
Output.Write('(') ; WriteGetTokenType ; Output.WriteString(' IN ') ; EmitSetAsParameters(to) ; Output.WriteString(')')
ELSE
i := 0 ;
first := TRUE ;
REPEAT
IF NOT IsEmptySet(to, i*MaxElementsInSet, (i+1)*MaxElementsInSet-1)
THEN
IF NOT first
THEN
Output.WriteString(' OR') ;
NewLine(Indent+ConditionIndent(m)) ;
DEC(Indent, ConditionIndent(m))
END ;
EmitIsInSubSet(to, i*MaxElementsInSet, (i+1)*MaxElementsInSet-1) ;
first := FALSE
END ;
INC(i) ;
UNTIL i*MaxElementsInSet>LargestValue
END
END
END EmitIsInFirst ;
(*
FlushCode -
*)
PROCEDURE FlushRecoverCode (VAR codeStack: FactorDesc) ;
BEGIN
IF codeStack#NIL
THEN
WHILE codeStack#NIL DO
EmitNonVarCode(codeStack^.code, 0, Indent) ;
codeStack := codeStack^.pushed
END
END
END FlushRecoverCode ;
(*
RecoverFactor -
*)
PROCEDURE RecoverFactor (f: FactorDesc; m: m2condition; codeStack: FactorDesc) ;
VAR
to: SetDesc ;
BEGIN
IF f=NIL
THEN
ELSE
EmitFileLineTag(f^.line) ;
WITH f^ DO
CASE type OF
id : to := NIL ;
CalcFirstFactor(f, NIL, to) ;
IF (to#NIL) AND (m#m2none)
THEN
RecoverCondition(m) ;
EmitIsInFirst(to, m) ;
CodeThenDo(m) ;
INC(Indent, 3)
END ;
FlushRecoverCode(codeStack) ;
IndentString('') ;
Output.WriteKey(ident^.name) ; Output.Write('(') ;
EmitStopParametersAndFollow(f, m) ; Output.WriteString(') ;') ; Output.WriteLn ;
RecoverFactor(f^.next, m2none, codeStack) ;
IF (to#NIL) AND (m#m2none)
THEN
DEC(Indent, 3)
END |
lit : IF m=m2none
THEN
FlushRecoverCode(codeStack) ;
IndentString('Expect(') ;
Output.WriteKey(GetSymKey(Aliases, string)) ; Output.WriteString(', ') ;
EmitStopParametersAndFollow(f, m) ; Output.WriteString(') ;') ; Output.WriteLn ;
RecoverFactor(f^.next, m2none, codeStack)
ELSE
RecoverCondition(m) ;
WriteGetTokenType ;
Output.Write('=') ;
Output.WriteKey(GetSymKey(Aliases, string)) ;
CodeThenDo(m) ;
INC(Indent, 3) ;
IndentString('Expect(') ;
Output.WriteKey(GetSymKey(Aliases, string)) ; Output.WriteString(', ') ;
EmitStopParametersAndFollow(f, m) ; Output.WriteString(') ;') ;
Output.WriteLn ;
FlushRecoverCode(codeStack) ;
RecoverFactor(f^.next, m2none, codeStack) ;
DEC(Indent, 3)
END |
sub: FlushRecoverCode(codeStack) ;
RecoverExpression(expr, m2none, m) ;
RecoverFactor(f^.next, m2none, codeStack) |
opt: FlushRecoverCode(codeStack) ;
IF OptExpSeen(f)
THEN
to := NIL ;
CalcFirstExpression(expr, NIL, to) ;
RecoverCondition(m) ;
EmitIsInFirst(to, m) ;
CodeThenDo(m) ;
INC(Indent, 3) ;
IndentString('(* seen optional [ | ] expression *)') ; Output.WriteLn ;
stop();
RecoverExpression(expr, m2none, m2if) ;
IndentString('(* end of optional [ | ] expression *)') ; Output.WriteLn ;
DEC(Indent, 3) ;
IndentString('END ;') ; Output.WriteLn
ELSE
RecoverExpression(expr, m2if, m)
END ;
RecoverFactor(f^.next, m2none, codeStack) |
mult: FlushRecoverCode(codeStack) ;
IF OptExpSeen(f) OR (m=m2if) OR (m=m2elsif)
THEN
to := NIL ;
CalcFirstExpression(expr, NIL, to) ;
RecoverCondition(m) ;
EmitIsInFirst(to, m) ;
CodeThenDo(m) ;
INC(Indent, 3) ;
IndentString('(* seen optional { | } expression *)') ; Output.WriteLn ;
RecoverCondition(m2while) ;
EmitIsInFirst(to, m2while) ;
CodeThenDo(m2while) ;
INC(Indent, 3) ;
RecoverExpression(expr, m2none, m2while) ;
IndentString('(* end of optional { | } expression *)') ; Output.WriteLn ;
DEC(Indent, 3) ;
IndentString('END ;') ; Output.WriteLn ;
DEC(Indent, 3) ;
IF m=m2none
THEN
IndentString('END ;') ; Output.WriteLn ;
DEC(Indent, 3)
END
ELSE
RecoverExpression(expr, m2while, m)
END ;
RecoverFactor(f^.next, m2none, codeStack) |
m2 : codeStack := ChainOn(codeStack, f) ;
IF f^.next=NIL
THEN
FlushRecoverCode(codeStack)
ELSE
RecoverFactor(f^.next, m, codeStack) (* was m2none *)
END
ELSE
END
END
END
END RecoverFactor ;
(*
OptExpSeen - returns TRUE if we can see an optional expression in the factor.
This is not the same as epsilon. Example { '+' } matches epsilon as
well as { '+' | '-' } but OptExpSeen returns TRUE in the second case
and FALSE in the first.
*)
PROCEDURE OptExpSeen (f: FactorDesc) : BOOLEAN ;
BEGIN
IF f=NIL
THEN
RETURN( FALSE )
ELSE
WITH f^ DO
CASE type OF
id ,
lit : RETURN( FALSE ) |
sub : RETURN( FALSE ) | (* is this correct? *)
opt ,
mult: RETURN( (expr#NIL) AND (expr^.term#NIL) AND (expr^.term^.next#NIL) ) |
m2 : RETURN( TRUE )
ELSE
END
END
END ;
WarnError('all cases were not handled') ;
WasNoError := FALSE
END OptExpSeen ;
(*
RecoverTerm -
*)
PROCEDURE RecoverTerm (t: TermDesc; new, old: m2condition) ;
VAR
LastWasM2Only, (* does the factor only contain inline code? *)
alternative : BOOLEAN ;
to : SetDesc ;
BEGIN
LastWasM2Only := (t^.factor^.type = m2) AND (t^.factor^.next = NIL) ;
to := NIL ;
CalcFirstTerm(t, NIL, to) ;
alternative := FALSE ;
IF t^.next#NIL
THEN
new := m2if
END ;
WHILE t#NIL DO
EmitFileLineTag(t^.line) ;
LastWasM2Only := (t^.factor^.type = m2) AND (t^.factor^.next = NIL) ;
IF (t^.factor^.type=m2) AND (new=m2elsif)
THEN
new := m2if ;
IndentString('ELSE') ; Output.WriteLn ;
INC(Indent, 3) ;
RecoverFactor(t^.factor, m2none, NIL) ;
alternative := FALSE
ELSE
RecoverFactor(t^.factor, new, NIL)
END ;
IF t^.next#NIL
THEN
new := m2elsif ;
alternative := TRUE
END ;
t := t^.next
END ;
IF (new=m2if) OR (new=m2elsif)
THEN
IF alternative AND (old#m2while)
THEN
IndentString('ELSE') ; Output.WriteLn ;
INC(Indent, 3) ;
IndentString('') ;
Output.WriteKey(ErrorProcArray) ;
Output.WriteString("('expecting one of: ") ;
EmitSetName(to, 0, 0) ;
Output.WriteString("')") ;
Output.WriteLn ;
DEC(Indent, 3)
ELSIF LastWasM2Only
THEN
DEC(Indent, 3)
END ;
IndentString('END ;') ; Output.WriteLn
ELSIF new=m2while
THEN
IndentString('END (* while *) ;') ; Output.WriteLn
ELSIF LastWasM2Only
THEN
DEC(Indent, 3)
END
END RecoverTerm ;
(*
RecoverExpression -
*)
PROCEDURE RecoverExpression (e: ExpressionDesc; new, old: m2condition) ;
BEGIN
IF e#NIL
THEN
EmitFileLineTag(e^.line) ;
RecoverTerm(e^.term, new, old)
END
END RecoverExpression ;
(*
RecoverStatement -
*)
PROCEDURE RecoverStatement (s: StatementDesc; m: m2condition) ;
BEGIN
IF s#NIL
THEN
EmitFileLineTag(s^.line) ;
RecoverExpression(s^.expr, m, m2none)
END
END RecoverStatement ;
(*
EmitFirstFactor - generate a list of all first tokens between the range: low..high.
*)
PROCEDURE EmitFirstFactor (f: FactorDesc; low, high: CARDINAL) ;
BEGIN
END EmitFirstFactor ;
(*
EmitUsed -
*)
PROCEDURE EmitUsed (wordno: CARDINAL) ;
BEGIN
IF NOT (wordno IN ParametersUsed)
THEN
Output.WriteString (" (* <* unused *> *) ")
END
END EmitUsed ;
(*
EmitStopParameters - generate the stop set.
*)
PROCEDURE EmitStopParameters (FormalParameters: BOOLEAN) ;
VAR
i: CARDINAL ;
BEGIN
IF LargestValue<=MaxElementsInSet
THEN
Output.WriteString('stopset') ;
IF FormalParameters
THEN
Output.WriteString(': SetOfStop') ;
EmitUsed (0)
ELSE
INCL (ParametersUsed, 0)
END
ELSE
i := 0 ;
REPEAT
Output.WriteString('stopset') ; Output.WriteCard(i, 0) ;
IF FormalParameters
THEN
Output.WriteString(': SetOfStop') ; Output.WriteCard(i, 0) ;
EmitUsed (i)
ELSE
INCL (ParametersUsed, i)
END ;
INC (i) ;
IF i*MaxElementsInSet<LargestValue
THEN
IF FormalParameters
THEN
Output.WriteString('; ')
ELSE
Output.WriteString(', ')
END
END
UNTIL i*MaxElementsInSet>=LargestValue ;
END
END EmitStopParameters ;
(*
IsBetween - returns TRUE if the value of the token, string, is
in the range: low..high
*)
PROCEDURE IsBetween (string: Name; low, high: WORD) : BOOLEAN ;
BEGIN
RETURN( (GetSymKey(Values, string) >= low) AND (GetSymKey(Values, string) <= high) )
END IsBetween ;
(*
IsEmptySet - returns TRUE if no elements exist in set, to, with values, low..high.
*)
PROCEDURE IsEmptySet (to: SetDesc; low, high: WORD) : BOOLEAN ;
BEGIN
WHILE to#NIL DO
WITH to^ DO
CASE type OF
tokel: IF IsBetween(string, low, high)
THEN
RETURN( FALSE )
END |
litel: IF IsBetween(GetSymKey(Aliases, string), low, high)
THEN
RETURN( FALSE )
END |
idel : WarnError('not expecting ident in first symbol list') ;
WasNoError := FALSE
ELSE
WarnError('unknown enuneration element') ;
WasNoError := FALSE
END
END ;
to := to^.next ;
END ;
RETURN( TRUE )
END IsEmptySet ;
(*
EmitSet - emits the tokens in the set, to, which have values low..high
*)
PROCEDURE EmitSet (to: SetDesc; low, high: WORD) ;
VAR
first: BOOLEAN ;
BEGIN
first := TRUE ;
WHILE to#NIL DO
WITH to^ DO
CASE type OF
tokel: IF (high=0) OR IsBetween(string, low, high)
THEN
IF NOT first
THEN
Output.WriteString(', ')
END ;
Output.WriteKey(string) ;
first := FALSE
END |
litel: IF (high=0) OR IsBetween(GetSymKey(Aliases, string), low, high)
THEN
IF NOT first
THEN
Output.WriteString(', ')
END ;
Output.WriteKey(GetSymKey(Aliases, string)) ;
first := FALSE
END |
idel : WarnError('not expecting ident in first symbol list') ;
WasNoError := FALSE
ELSE
WarnError('unknown enuneration element') ;
WasNoError := FALSE
END
END ;
to := to^.next
END
END EmitSet ;
(*
EmitSetName - emits the tokens in the set, to, which have values low..high, using
their names.
*)
PROCEDURE EmitSetName (to: SetDesc; low, high: WORD) ;
BEGIN
WHILE to#NIL DO
WITH to^ DO
CASE type OF
tokel: IF (high=0) OR IsBetween(string, low, high)
THEN
IF MakeKey("'")=GetSymKey(ReverseAliases, string)
THEN
Output.WriteString('single quote')
ELSE
KeyWord(GetSymKey(ReverseAliases, string))
END
END |
litel: IF (high=0) OR IsBetween(GetSymKey(Aliases, string), low, high)
THEN
Output.WriteKey(string)
END |
idel : WarnError('not expecting ident in first symbol list') ;
WasNoError := FALSE
ELSE
WarnError('unknown enuneration element') ;
WasNoError := FALSE
END
END ;
to := to^.next ;
IF to#NIL
THEN
Output.Write(' ')
END
END
END EmitSetName ;
(*
EmitStopParametersAndSet - generates the stop parameters together with a set
inclusion of all the symbols in set, to.
*)
PROCEDURE EmitStopParametersAndSet (to: SetDesc) ;
VAR
i : CARDINAL ;
BEGIN
IF LargestValue<=MaxElementsInSet
THEN
Output.WriteString('stopset') ;
INCL (ParametersUsed, 0) ;
IF (to#NIL) AND (NumberOfElements(to, 0, MaxElementsInSet-1)>0)
THEN
Output.WriteString(' + SetOfStop') ;
Output.Write('{') ;
EmitSet(to, 0, MaxElementsInSet-1) ;
Output.Write('}')
END
ELSE
i := 0 ;
REPEAT
Output.WriteString('stopset') ; Output.WriteCard(i, 0) ;
INCL (ParametersUsed, i) ;
IF (to#NIL) AND (NumberOfElements(to, i*MaxElementsInSet, (i+1)*MaxElementsInSet-1)>0)
THEN
Output.WriteString(' + SetOfStop') ; Output.WriteCard(i, 0) ;
Output.Write('{') ;
EmitSet(to, i*MaxElementsInSet, (i+1)*MaxElementsInSet-1) ;
Output.Write('}')
END ;
INC(i) ;
IF i*MaxElementsInSet<LargestValue
THEN
Output.WriteString(', ')
END
UNTIL i*MaxElementsInSet>=LargestValue
END
END EmitStopParametersAndSet ;
(*
EmitSetAsParameters - generates the first symbols as parameters to a set function.
*)
PROCEDURE EmitSetAsParameters (to: SetDesc) ;
VAR
i : CARDINAL ;
BEGIN
IF LargestValue<=MaxElementsInSet
THEN
Output.Write('{') ;
EmitSet(to, 0, MaxElementsInSet-1)
ELSE
i := 0 ;
REPEAT
Output.Write('{') ;
EmitSet(to, i*MaxElementsInSet, (i+1)*MaxElementsInSet-1) ;
INC(i) ;
IF (i+1)*MaxElementsInSet>LargestValue
THEN
Output.WriteString('}, ')
END
UNTIL (i+1)*MaxElementsInSet>=LargestValue ;
END ;
Output.Write('}')
END EmitSetAsParameters ;
(*
EmitStopParametersAndFollow - generates the stop parameters together with a set
inclusion of all the follow symbols for subsequent
sentances.
*)
PROCEDURE EmitStopParametersAndFollow (f: FactorDesc; m: m2condition) ;
VAR
to: SetDesc ;
BEGIN
to := NIL ;
(*
IF m=m2while
THEN
CalcFirstFactor(f, NIL, to)
END ;
*)
CollectFollow(to, f^.followinfo) ;
EmitStopParametersAndSet(to) ;
IF Debugging
THEN
Output.WriteLn ;
Output.WriteString('factor is: ') ;
PrettyCommentFactor(f, StrLen('factor is: ')) ;
Output.WriteLn ;
Output.WriteString('follow set:') ;
EmitSet(to, 0, 0) ;
Output.WriteLn
END
END EmitStopParametersAndFollow ;
(*
EmitFirstAsParameters -
*)
PROCEDURE EmitFirstAsParameters (f: FactorDesc) ;
VAR
to: SetDesc ;
BEGIN
to := NIL ;
CalcFirstFactor(f, NIL, to) ;
EmitSetAsParameters(to)
END EmitFirstAsParameters ;
(*
RecoverProduction - only encode grammer rules which are not special.
Generate error recovery code.
*)
PROCEDURE RecoverProduction (p: ProductionDesc) ;
VAR
s: String ;
BEGIN
IF (p#NIL) AND ((NOT p^.firstsolved) OR ((p^.statement#NIL) AND (p^.statement^.expr#NIL)))
THEN
BeginningOfLine := TRUE ;
Indent := 0 ;
Output.WriteLn ;
OnLineStart := FALSE ;
EmitFileLineTag(p^.line) ;
IndentString('PROCEDURE ') ;
Output.WriteKey(GetDefinitionName(p)) ;
Output.WriteString(' (') ;
ParametersUsed := {} ;
Output.StartBuffer ;
Output.WriteString(') ;') ;
VarProduction(p) ;
Output.WriteLn ;
OnLineStart := FALSE ;
EmitFileLineTag(p^.line) ;
Indent := 0 ;
IndentString('BEGIN') ; Output.WriteLn ;
OnLineStart := FALSE ;
EmitFileLineTag(p^.line) ;
Indent := 3 ;
RecoverStatement(p^.statement, m2none) ;
Indent := 0 ;
IndentString('END ') ; Output.WriteKey(GetDefinitionName(p)) ; Output.WriteString(' ;') ;
Output.WriteLn ;
Output.WriteLn ;
Output.WriteLn ;
s := Output.EndBuffer () ;
EmitStopParameters (TRUE) ;
Output.KillWriteS (s)
END
END RecoverProduction ;
(*
IsWhite - returns TRUE if, ch, is a space or a tab.
*)
PROCEDURE IsWhite (ch: CHAR) : BOOLEAN ;
BEGIN
RETURN( (ch=' ') OR (ch=tab) OR (ch=lf) )
END IsWhite ;
(*
FindStr - returns TRUE if, str, was seen inside the code hunk
*)
PROCEDURE FindStr (VAR code: CodeHunk; VAR i: CARDINAL; str: ARRAY OF CHAR) : BOOLEAN ;
VAR
j, k: CARDINAL ;
t : CodeHunk ;
BEGIN
t := code ;
k := StrLen(code^.codetext)+1 ;
j := StrLen(str) ;
WHILE t#NIL DO
REPEAT
WHILE (k>0) AND IsWhite(t^.codetext[k-1]) DO
DEC(k)
END ;
IF k=0
THEN
t := t^.next ;
k := MaxCodeHunkLength+1
END
UNTIL (t=NIL) OR (NOT IsWhite(t^.codetext[k-1])) ;
(* found another word check it *)
IF t#NIL
THEN
j := StrLen(str) ;
i := k ;
WHILE (t#NIL) AND (j>0) AND ((str[j-1]=t^.codetext[k-1]) OR
(IsWhite(str[j-1]) AND IsWhite(t^.codetext[k-1]))) DO
DEC(j) ;
DEC(k) ;
IF j=0
THEN
(* found word remember position *)
code := t
END ;
IF k=0
THEN
t := t^.next ;
k := MaxCodeHunkLength+1
END
END ;
IF k>0
THEN
DEC(k)
ELSE
t := t^.next
END
END ;
END ;
RETURN( (t=NIL) AND (j=0) )
END FindStr ;
(*
WriteUpto -
*)
PROCEDURE WriteUpto (code, upto: CodeHunk; limit: CARDINAL) ;
BEGIN
IF code#upto
THEN
WriteUpto(code^.next, upto, limit) ;
Output.WriteString(code^.codetext)
ELSE
WHILE (limit<=MaxCodeHunkLength) AND (code^.codetext[limit]#nul) DO
Output.Write(code^.codetext[limit]) ;
INC(limit)
END
END
END WriteUpto ;
(*
CheckForVar - checks for any local variables which need to be emitted during
this production.
*)
PROCEDURE CheckForVar (code: CodeHunk) ;
VAR
i: CARDINAL ;
t: CodeHunk ;
BEGIN
t := code ;
IF FindStr(t, i, 'VAR') AND EmitCode
THEN
IF NOT EmittedVar
THEN
Output.WriteLn ;
Indent := 0 ;
IndentString('VAR') ;
INC(Indent, 3) ;
Output.WriteLn ;
EmittedVar := TRUE ;
END ;
WriteUpto(code, t, i)
END
END CheckForVar ;
(*
VarFactor -
*)
PROCEDURE VarFactor (f: FactorDesc) ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : |
lit : |
sub ,
opt ,
mult: VarExpression(expr) |
m2 : CheckForVar(code^.code)
ELSE
END
END ;
f := f^.next
END
END VarFactor ;
(*
VarTerm -
*)
PROCEDURE VarTerm (t: TermDesc) ;
BEGIN
WHILE t#NIL DO
VarFactor(t^.factor) ;
t := t^.next
END
END VarTerm ;
(*
VarExpression -
*)
PROCEDURE VarExpression (e: ExpressionDesc) ;
BEGIN
IF e#NIL
THEN
VarTerm(e^.term)
END
END VarExpression ;
(*
VarStatement -
*)
PROCEDURE VarStatement (s: StatementDesc) ;
BEGIN
IF s#NIL
THEN
VarExpression(s^.expr)
END
END VarStatement ;
(*
VarProduction - writes out all variable declarations.
*)
PROCEDURE VarProduction (p: ProductionDesc) ;
BEGIN
EmittedVar := FALSE ;
IF p#NIL
THEN
VarStatement(p^.statement)
END
END VarProduction ;
(*
In - returns TRUE if token, s, is already in the set, to.
*)
PROCEDURE In (to: SetDesc; s: Name) : BOOLEAN ;
BEGIN
WHILE to#NIL DO
WITH to^ DO
CASE type OF
idel : IF s=ident^.name
THEN
RETURN( TRUE )
END |
tokel,
litel : IF s=string
THEN
RETURN( TRUE )
END
ELSE
WarnError('internal error CASE type not known') ;
WasNoError := FALSE
END
END ;
to := to^.next
END ;
RETURN( FALSE )
END In ;
(*
IntersectionIsNil - given two set lists, s1, s2, return TRUE if the
s1 * s2 = {}
*)
PROCEDURE IntersectionIsNil (s1, s2: SetDesc) : BOOLEAN ;
BEGIN
WHILE s1#NIL DO
WITH s1^ DO
CASE type OF
idel : IF In(s2, ident^.name)
THEN
RETURN( FALSE )
END |
tokel,
litel: IF In(s2, string)
THEN
RETURN( FALSE )
END
ELSE
WarnError('internal error CASE type not known') ;
WasNoError := FALSE
END
END ;
s1 := s1^.next
END ;
RETURN( TRUE )
END IntersectionIsNil ;
(*
AddSet - adds a first symbol to a production.
*)
PROCEDURE AddSet (VAR to: SetDesc; s: Name) ;
VAR
d: SetDesc ;
BEGIN
IF NOT In(to, s)
THEN
d := NewSetDesc() ;
WITH d^ DO
type := tokel ;
string := s ;
next := to ;
END ;
to := d ;
Finished := FALSE
END
END AddSet ;
(*
OrSet -
*)
PROCEDURE OrSet (VAR to: SetDesc; from: SetDesc) ;
BEGIN
WHILE from#NIL DO
WITH from^ DO
CASE type OF
tokel: AddSet(to, string) |
litel: AddSet(to, GetSymKey(Aliases, string)) |
idel : WarnError('not expecting ident in first symbol list') ;
WasNoError := FALSE
ELSE
Halt('unknown element in enumeration type',
__FILE__, __FUNCTION__, __LINE__)
END
END ;
from := from^.next
END
END OrSet ;
(*
CalcFirstFactor -
*)
PROCEDURE CalcFirstFactor (f: FactorDesc; from: ProductionDesc; VAR to: SetDesc) ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : IF ident^.definition=NIL
THEN
WarnError1("no rule found for an 'ident' called '%s'", ident^.name) ;
HALT
END ;
OrSet(to, ident^.definition^.first) ;
IF GetReachEnd(ident^.definition^.followinfo)=false
THEN
RETURN
END |
lit : IF GetSymKey(Aliases, string)=NulKey
THEN
WarnError1("unknown token for '%s'", string) ;
WasNoError := FALSE
ELSE
AddSet(to, GetSymKey(Aliases, string))
END ;
RETURN |
sub ,
opt ,
mult: CalcFirstExpression(expr, from, to) |
m2 :
ELSE
END
END ;
f := f^.next
END
END CalcFirstFactor ;
(*
CalcFirstTerm -
*)
PROCEDURE CalcFirstTerm (t: TermDesc; from: ProductionDesc; VAR to: SetDesc) ;
BEGIN
WHILE t#NIL DO
CalcFirstFactor(t^.factor, from, to) ;
t := t^.next
END
END CalcFirstTerm ;
(*
CalcFirstExpression -
*)
PROCEDURE CalcFirstExpression (e: ExpressionDesc; from: ProductionDesc; VAR to: SetDesc) ;
BEGIN
IF e#NIL
THEN
CalcFirstTerm(e^.term, from, to)
END
END CalcFirstExpression ;
(*
CalcFirstStatement -
*)
PROCEDURE CalcFirstStatement (s: StatementDesc; from: ProductionDesc; VAR to: SetDesc) ;
BEGIN
IF s#NIL
THEN
CalcFirstExpression(s^.expr, from, to)
END
END CalcFirstStatement ;
(*
CalcFirstProduction - calculates all of the first symbols for the grammer
*)
PROCEDURE CalcFirstProduction (p: ProductionDesc; from: ProductionDesc; VAR to: SetDesc) ;
VAR
s: SetDesc ;
BEGIN
IF p#NIL
THEN
IF p^.firstsolved
THEN
s := p^.first ;
WHILE s#NIL DO
CASE s^.type OF
idel : CalcFirstProduction(s^.ident^.definition, from, to) |
tokel,
litel: AddSet(to, s^.string)
ELSE
END ;
s := s^.next
END
ELSE
CalcFirstStatement(p^.statement, from, to)
END
END
END CalcFirstProduction ;
(*
WorkOutFollow -
*)
PROCEDURE WorkOutFollowFactor (f: FactorDesc; VAR followset: SetDesc; after: SetDesc) ;
VAR
foundepsilon,
canreachend : TraverseResult ;
BEGIN
foundepsilon := true ;
canreachend := true ;
WHILE (f#NIL) AND (foundepsilon=true) DO
WITH f^ DO
CASE type OF
id : IF ident^.definition=NIL
THEN
WarnError1("no rule found for an 'ident' called '%s'", ident^.name) ;
HALT
END ;
OrSet(followset, ident^.definition^.first) |
lit : AddSet(followset, GetSymKey(Aliases, string)) |
sub : WorkOutFollowExpression(expr, followset, NIL) |
opt : WorkOutFollowExpression(expr, followset, NIL) |
mult: WorkOutFollowExpression(expr, followset, NIL) |
m2 :
ELSE
END
END ;
IF GetEpsilon(f^.followinfo)=unknown
THEN
WarnError('internal error: epsilon unknown') ;
PrettyCommentFactor(f, 3) ;
WasNoError := FALSE
END ;
foundepsilon := GetEpsilon(f^.followinfo) ;
canreachend := GetReachEnd(f^.followinfo) ; (* only goes from FALSE -> TRUE *)
f := f^.next
END ;
IF canreachend=true
THEN
OrSet(followset, after)
END
END WorkOutFollowFactor ;
(*
WorkOutFollowTerm -
*)
PROCEDURE WorkOutFollowTerm (t: TermDesc; VAR followset: SetDesc; after: SetDesc) ;
BEGIN
IF t#NIL
THEN
WHILE t#NIL DO
WITH t^ DO
WorkOutFollowFactor(factor, followset, after) ; (* { '|' Term } *)
END ;
t := t^.next
END
END
END WorkOutFollowTerm ;
(*
WorkOutFollowExpression -
*)
PROCEDURE WorkOutFollowExpression (e: ExpressionDesc; VAR followset: SetDesc; after: SetDesc) ;
BEGIN
IF e#NIL
THEN
WITH e^ DO
WorkOutFollowTerm(term, followset, after)
END
END
END WorkOutFollowExpression ;
(*
CollectFollow - collects the follow set from, f, into, to.
*)
PROCEDURE CollectFollow (VAR to: SetDesc; f: FollowDesc) ;
BEGIN
OrSet(to, f^.follow)
END CollectFollow ;
(*
CalcFollowFactor -
*)
PROCEDURE CalcFollowFactor (f: FactorDesc; after: SetDesc) ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : WorkOutFollowFactor(next, followinfo^.follow, after) |
lit : WorkOutFollowFactor(next, followinfo^.follow, after) |
opt ,
sub : CalcFirstFactor(next, NIL, followinfo^.follow) ;
IF (next=NIL) OR (GetReachEnd(next^.followinfo)=true)
THEN
OrSet(followinfo^.follow, after) ;
CalcFollowExpression(expr, followinfo^.follow)
ELSE
CalcFollowExpression(expr, followinfo^.follow)
END |
mult: CalcFirstFactor(f, NIL, followinfo^.follow) ;
(* include first as we may repeat this sentance *)
IF Debugging
THEN
WriteLn ;
WriteString('found mult: and first is: ') ; EmitSet(followinfo^.follow, 0, 0) ; WriteLn
END ;
IF (next=NIL) OR (GetReachEnd(next^.followinfo)=true)
THEN
OrSet(followinfo^.follow, after) ;
CalcFollowExpression(expr, followinfo^.follow)
ELSE
CalcFollowExpression(expr, followinfo^.follow)
END
ELSE
END
END ;
f := f^.next
END
END CalcFollowFactor ;
(*
CalcFollowTerm -
*)
PROCEDURE CalcFollowTerm (t: TermDesc; after: SetDesc) ;
BEGIN
IF t#NIL
THEN
WHILE t#NIL DO
WITH t^ DO
CalcFollowFactor(factor, after) ; (* { '|' Term } *)
END ;
t := t^.next
END
END
END CalcFollowTerm ;
(*
CalcFollowExpression -
*)
PROCEDURE CalcFollowExpression (e: ExpressionDesc; after: SetDesc) ;
BEGIN
IF e#NIL
THEN
WITH e^ DO
CalcFollowTerm(term, after)
END
END
END CalcFollowExpression ;
(*
CalcFollowStatement - given a bnf statement generate the follow set.
*)
PROCEDURE CalcFollowStatement (s: StatementDesc) ;
BEGIN
IF s#NIL
THEN
WITH s^ DO
CalcFollowExpression(expr, NIL)
END
END
END CalcFollowStatement ;
(*
CalcFollowProduction -
*)
PROCEDURE CalcFollowProduction (p: ProductionDesc) ;
BEGIN
IF p#NIL
THEN
WITH p^ DO
CalcFollowStatement(statement)
END
END
END CalcFollowProduction ;
(*
CalcEpsilonFactor -
*)
PROCEDURE CalcEpsilonFactor (f: FactorDesc) ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : AssignEpsilon(GetEpsilon(ident^.definition^.followinfo)#unknown,
followinfo, GetEpsilon(ident^.definition^.followinfo)) |
lit : AssignEpsilon(TRUE, followinfo, false) |
sub : CalcEpsilonExpression(expr) ;
AssignEpsilon(GetEpsilon(expr^.followinfo)#unknown,
followinfo, GetEpsilon(expr^.followinfo)) |
m2 : AssignEpsilon(TRUE, followinfo, true) |
opt ,
mult: CalcEpsilonExpression(expr) ;
AssignEpsilon(TRUE, followinfo, true)
ELSE
END
END ;
f := f^.next
END
END CalcEpsilonFactor ;
(*
CalcEpsilonTerm -
*)
PROCEDURE CalcEpsilonTerm (t: TermDesc) ;
BEGIN
IF t#NIL
THEN
WHILE t#NIL DO
WITH t^ DO
IF factor#NIL
THEN
CASE GetReachEnd(factor^.followinfo) OF
true : AssignEpsilon(TRUE, followinfo, true) |
false: AssignEpsilon(TRUE, followinfo, false) |
unknown:
ELSE
END
END ;
CalcEpsilonFactor(factor) (* { '|' Term } *)
END ;
t := t^.next
END
END
END CalcEpsilonTerm ;
(*
CalcEpsilonExpression -
*)
PROCEDURE CalcEpsilonExpression (e: ExpressionDesc) ;
VAR
t : TermDesc ;
result: TraverseResult ;
BEGIN
IF e#NIL
THEN
CalcEpsilonTerm(e^.term) ;
IF GetEpsilon(e^.followinfo)=unknown
THEN
result := unknown ;
WITH e^ DO
t := term ;
WHILE t#NIL DO
IF GetEpsilon(t^.followinfo)#unknown
THEN
stop
END ;
CASE GetEpsilon(t^.followinfo) OF
unknown: |
true : result := true |
false : IF result#true
THEN
result := false
END
ELSE
END ;
t := t^.next
END
END ;
AssignEpsilon(result#unknown, e^.followinfo, result)
END
END
END CalcEpsilonExpression ;
(*
CalcEpsilonStatement - given a bnf statement generate the follow set.
*)
PROCEDURE CalcEpsilonStatement (s: StatementDesc) ;
BEGIN
IF s#NIL
THEN
WITH s^ DO
IF expr#NIL
THEN
AssignEpsilon(GetEpsilon(expr^.followinfo)#unknown,
followinfo, GetEpsilon(expr^.followinfo))
END ;
CalcEpsilonExpression(expr)
END
END
END CalcEpsilonStatement ;
(*
CalcEpsilonProduction -
*)
PROCEDURE CalcEpsilonProduction (p: ProductionDesc) ;
BEGIN
IF p#NIL
THEN
(*
IF p^.statement^.ident^.name=MakeKey('DefinitionModule')
THEN
stop
END ;
*)
IF Debugging
THEN
WriteKey(p^.statement^.ident^.name) ;
WriteString(' calculating epsilon') ;
WriteLn
END ;
WITH p^ DO
AssignEpsilon(GetEpsilon(statement^.followinfo)#unknown,
followinfo, GetEpsilon(statement^.followinfo)) ;
CalcEpsilonStatement(statement)
END
END
END CalcEpsilonProduction ;
(*
CalcReachEndFactor -
*)
PROCEDURE CalcReachEndFactor (f: FactorDesc) : TraverseResult ;
VAR
canreachend,
result : TraverseResult ;
BEGIN
IF f=NIL
THEN
RETURN( true ) (* we have reached the end of this factor list *)
ELSE
WITH f^ DO
(* we need to traverse all factors even if we can short cut the answer to this list of factors *)
result := CalcReachEndFactor(next) ;
CASE type OF
id : IF ident^.definition=NIL
THEN
WarnError1('definition for %s is absent (assuming epsilon is false for this production)', ident^.name) ;
result := false
ELSIF result#false
THEN
CASE GetReachEnd(ident^.definition^.followinfo) OF
false : result := false |
true : |
unknown: result := unknown
ELSE
END
END |
lit : result := false |
sub : CalcReachEndExpression(expr) ;
IF (expr#NIL) AND (result=true)
THEN
result := GetReachEnd(expr^.followinfo)
END |
mult,
opt : IF expr#NIL
THEN
(* not interested in the result as expression is optional *)
CalcReachEndExpression(expr)
END |
m2 :
ELSE
END ;
AssignReachEnd(result#unknown, followinfo, result)
END ;
RETURN( result )
END
END CalcReachEndFactor ;
(*
CalcReachEndTerm -
*)
PROCEDURE CalcReachEndTerm (t: TermDesc) : TraverseResult ;
VAR
canreachend,
result : TraverseResult ;
BEGIN
IF t#NIL
THEN
canreachend := false ;
WHILE t#NIL DO
WITH t^ DO
result := CalcReachEndFactor(factor) ;
AssignReachEnd(result#unknown, followinfo, result) ;
CASE result OF
true : canreachend := true |
false : |
unknown: IF canreachend=false
THEN
canreachend := unknown
END
ELSE
END
END ;
t := t^.next (* { '|' Term } *)
END ;
RETURN( canreachend )
END
END CalcReachEndTerm ;
(*
CalcReachEndExpression -
*)
PROCEDURE CalcReachEndExpression (e: ExpressionDesc) ;
VAR
result: TraverseResult ;
BEGIN
IF e=NIL
THEN
(* no expression, thus reached the end of this sentance *)
ELSE
WITH e^ DO
result := CalcReachEndTerm(term) ;
AssignReachEnd(result#unknown, followinfo, result)
END
END
END CalcReachEndExpression ;
(*
CalcReachEndStatement -
*)
PROCEDURE CalcReachEndStatement (s: StatementDesc) ;
BEGIN
IF s#NIL
THEN
WITH s^ DO
IF expr#NIL
THEN
CalcReachEndExpression(expr) ;
AssignReachEnd(GetReachEnd(expr^.followinfo)#unknown,
followinfo, GetReachEnd(expr^.followinfo))
END
END
END
END CalcReachEndStatement ;
PROCEDURE stop ; BEGIN END stop ;
(*
CalcReachEndProduction -
*)
PROCEDURE CalcReachEndProduction (p: ProductionDesc) ;
BEGIN
IF p#NIL
THEN
WITH p^ DO
CalcReachEndStatement(statement) ;
IF GetReachEnd(followinfo)#unknown
THEN
IF Debugging
THEN
WriteString('already calculated reach end for: ') ;
WriteKey(p^.statement^.ident^.name) ; WriteString(' its value is ') ;
IF GetReachEnd(followinfo)=true
THEN
WriteString('reachable')
ELSE
WriteString('non reachable')
END ;
WriteLn
END
END ;
AssignReachEnd(GetReachEnd(statement^.followinfo)#unknown, followinfo, GetReachEnd(statement^.followinfo)) ;
END
END
END CalcReachEndProduction ;
(*
EmptyFactor -
*)
PROCEDURE EmptyFactor (f: FactorDesc) : BOOLEAN ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : IF NOT EmptyProduction(ident^.definition)
THEN
RETURN( FALSE )
END |
lit : RETURN( FALSE ) |
sub : IF NOT EmptyExpression(expr)
THEN
RETURN( FALSE )
END |
opt ,
mult: RETURN( TRUE ) |
m2 :
ELSE
END
END ;
f := f^.next
END ;
RETURN( TRUE )
END EmptyFactor ;
(*
EmptyTerm - returns TRUE if the term maybe empty.
*)
PROCEDURE EmptyTerm (t: TermDesc) : BOOLEAN ;
BEGIN
WHILE t#NIL DO
IF EmptyFactor(t^.factor)
THEN
RETURN( TRUE )
ELSE
t := t^.next
END
END ;
RETURN( FALSE )
END EmptyTerm ;
(*
EmptyExpression -
*)
PROCEDURE EmptyExpression (e: ExpressionDesc) : BOOLEAN ;
BEGIN
IF e=NIL
THEN
RETURN( TRUE )
ELSE
RETURN( EmptyTerm(e^.term) )
END
END EmptyExpression ;
(*
EmptyStatement - returns TRUE if statement, s, is empty.
*)
PROCEDURE EmptyStatement (s: StatementDesc) : BOOLEAN ;
BEGIN
IF s=NIL
THEN
RETURN( TRUE )
ELSE
RETURN( EmptyExpression(s^.expr) )
END
END EmptyStatement ;
(*
EmptyProduction - returns if production, p, maybe empty.
*)
PROCEDURE EmptyProduction (p: ProductionDesc) : BOOLEAN ;
BEGIN
IF p=NIL
THEN
WarnError('unknown production') ;
RETURN( TRUE )
ELSIF (p^.firstsolved) AND (p^.first#NIL)
THEN
(* predefined but first set to something - thus not empty *)
RETURN( FALSE )
ELSE
RETURN( EmptyStatement(p^.statement) )
END
END EmptyProduction ;
(*
EmitFDLNotice -
*)
PROCEDURE EmitFDLNotice ;
BEGIN
Output.WriteString('@c Copyright (C) 2000-2025 Free Software Foundation, Inc.') ; Output.WriteLn ;
Output.WriteLn ;
Output.WriteString('@c This file is part of GCC.') ; Output.WriteLn ;
Output.WriteString('@c Permission is granted to copy, distribute and/or modify this document') ; Output.WriteLn ;
Output.WriteString('@c under the terms of the GNU Free Documentation License, Version 1.2 or') ; Output.WriteLn ;
Output.WriteString('@c any later version published by the Free Software Foundation.') ; Output.WriteLn
END EmitFDLNotice ;
(*
EmitRules - generates the BNF rules.
*)
PROCEDURE EmitRules ;
BEGIN
IF Texinfo AND FreeDocLicense
THEN
EmitFDLNotice
END ;
ForeachRuleDo(EmitRule)
END EmitRules ;
(*
DescribeElement -
*)
PROCEDURE DescribeElement (name: WORD) ;
VAR
lit: Name ;
BEGIN
IF InitialElement
THEN
InitialElement := FALSE
ELSE
Output.WriteString(' |')
END ;
Output.WriteLn ;
Indent := 3 ;
IndentString('') ;
Output.WriteKey(name) ;
Output.WriteString(': ') ;
lit := GetSymKey(ReverseAliases, name) ;
IF MakeKey('"')=lit
THEN
Output.WriteString('str := ConCat(ConCatChar(ConCatChar(InitString("syntax error, found ') ;
Output.Write("'") ; Output.WriteString('"), ') ;
Output.Write("'") ; Output.Write('"') ; Output.Write("'") ; Output.WriteString("), ") ;
Output.Write('"') ; Output.Write("'") ; Output.Write('"') ; Output.WriteString("), Mark(str))")
ELSIF MakeKey("'")=lit
THEN
Output.WriteString("str := ConCat(ConCatChar(ConCatChar(InitString('syntax error, found ") ;
Output.Write('"') ; Output.WriteString("'), ") ;
Output.Write('"') ; Output.Write("'") ; Output.Write('"') ; Output.WriteString('), ') ;
Output.Write("'") ; Output.Write('"') ; Output.Write("'") ; Output.WriteString('), Mark(str))')
ELSE
Output.WriteString("str := ConCat(InitString(") ; Output.Write('"') ;
Output.WriteString("syntax error, found ") ; KeyWord(lit) ; Output.WriteString('"), Mark(str))')
END
END DescribeElement ;
(*
EmitInTestStop - construct a test for stop element, name.
*)
PROCEDURE EmitInTestStop (name: Name) ;
VAR
i, value: CARDINAL ;
BEGIN
IF LargestValue<=MaxElementsInSet
THEN
Output.WriteKey(name) ; Output.WriteString(' IN stopset') ;
INCL (ParametersUsed, 0)
ELSE
value := GetSymKey(Values, name) ;
i := value DIV MaxElementsInSet ;
Output.WriteKey(name) ; Output.WriteString(' IN stopset') ; Output.WriteCard(i, 0) ;
INCL (ParametersUsed, i)
END
END EmitInTestStop ;
(*
DescribeStopElement -
*)
PROCEDURE DescribeStopElement (name: WORD) ;
VAR
lit: Name ;
BEGIN
Indent := 3 ;
IndentString('IF ') ; EmitInTestStop(name) ; Output.WriteLn ;
IndentString('THEN') ; Output.WriteLn ;
Indent := 6 ;
lit := GetSymKey(ReverseAliases, name) ;
IF (lit=NulName) OR (lit=MakeKey(''))
THEN
IndentString('(* ') ;
Output.WriteKey(name) ;
Output.WriteString(' has no token name (needed to generate error messages) *)')
ELSIF MakeKey("'")=lit
THEN
IndentString('message := ConCatChar(ConCatChar(ConCatChar(ConCatChar(ConCatChar(message, ') ;
Output.WriteString("' '), ") ;
Output.Write("'") ; Output.Write('"') ; Output.WriteString("'), ") ;
Output.Write('"') ; Output.Write("'") ; Output.WriteString('"), ') ;
Output.Write("'") ; Output.Write('"') ; Output.WriteString("'), ',') ; INC(n) ; ")
ELSIF MakeKey('"')=lit
THEN
IndentString("message := ConCatChar(ConCatChar(ConCatChar(ConCatChar(ConCatChar(message, ") ;
Output.WriteString('" "), ') ;
Output.Write('"') ; Output.Write("`") ; Output.WriteString('"), ') ;
Output.Write("'") ; Output.Write('"') ; Output.WriteString("'), ") ;
Output.Write('"') ; Output.Write("'") ; Output.WriteString('"), ",") ; INC(n) ; ')
ELSE
IndentString("message := ConCat(ConCatChar(message, ' ") ; Output.WriteString("'), ") ;
Output.WriteString('Mark(InitString("') ; KeyWord(lit) ; Output.Write('"') ;
Output.WriteString('))) ; INC(n)')
END ;
Output.WriteLn ;
Indent := 3 ;
IndentString('END ;') ; Output.WriteLn
END DescribeStopElement ;
(*
EmitDescribeStop -
*)
PROCEDURE EmitDescribeStop ;
VAR
s: String ;
BEGIN
Output.WriteLn ;
Indent := 0 ;
IndentString('(*') ;
Indent := 3 ;
Output.WriteLn ;
IndentString('DescribeStop - issues a message explaining what tokens were expected') ;
Output.WriteLn ;
Output.WriteString('*)') ;
Output.WriteLn ;
Output.WriteLn ;
Indent := 0 ;
IndentString('PROCEDURE DescribeStop (') ;
ParametersUsed := {} ;
Output.StartBuffer ;
Output.WriteString(') : String ;') ;
Output.WriteLn ;
IndentString('VAR') ; Output.WriteLn ;
Indent := 3 ;
IndentString('n : CARDINAL ;') ; Output.WriteLn ;
IndentString('str,') ; Output.WriteLn ;
IndentString('message: String ;') ; Output.WriteLn ;
Indent := 0 ;
IndentString('BEGIN') ; Output.WriteLn ;
Indent := 3 ;
IndentString('n := 0 ;') ; Output.WriteLn ;
IndentString("message := InitString('') ;") ;
Output.WriteLn ;
ForeachNodeDo(Aliases, DescribeStopElement) ; Output.WriteLn ;
Indent := 3 ;
IndentString('IF n=0') ; Output.WriteLn ;
IndentString('THEN') ; Output.WriteLn ;
Indent := 6 ;
IndentString("str := InitString(' syntax error') ; ") ; Output.WriteLn ;
IndentString('message := KillString(message) ; ') ; Output.WriteLn ;
Indent := 3 ;
IndentString('ELSIF n=1') ; Output.WriteLn ;
IndentString('THEN') ; Output.WriteLn ;
Indent := 6 ;
IndentString("str := ConCat(message, Mark(InitString(' missing '))) ;") ; Output.WriteLn ;
Indent := 3 ;
IndentString('ELSE') ; Output.WriteLn ;
Indent := 6 ;
IndentString("str := ConCat(InitString(' expecting one of'), message) ;") ; Output.WriteLn ;
IndentString("message := KillString(message) ;") ; Output.WriteLn ;
Indent := 3 ;
IndentString('END ;') ; Output.WriteLn ;
IndentString('RETURN( str )') ; Output.WriteLn ;
Indent := 0 ;
IndentString('END DescribeStop ;') ; Output.WriteLn ;
Output.WriteLn ;
s := Output.EndBuffer () ;
EmitStopParameters(TRUE) ;
Output.KillWriteS (s)
END EmitDescribeStop ;
(*
EmitDescribeError -
*)
PROCEDURE EmitDescribeError ;
BEGIN
Output.WriteLn ;
Indent := 0 ;
IndentString('(*') ; Output.WriteLn ;
Indent := 3 ;
IndentString('DescribeError - issues a message explaining what tokens were expected') ; Output.WriteLn ;
Indent := 0 ;
IndentString('*)') ;
Output.WriteLn ;
Output.WriteLn ;
IndentString('PROCEDURE DescribeError ;') ;
Output.WriteLn ;
IndentString('VAR') ; Output.WriteLn ;
Indent := 3 ;
IndentString('str: String ;') ; Output.WriteLn ;
Indent := 0 ;
IndentString('BEGIN') ; Output.WriteLn ;
Indent := 3 ;
IndentString("str := InitString('') ;") ; Output.WriteLn ;
(* was
IndentString('str := DescribeStop(') ; EmitStopParameters(FALSE) ; Output.WriteString(') ;') ; Output.WriteLn ;
*)
IndentString('CASE ') ; WriteGetTokenType ; Output.WriteString(' OF') ; NewLine(3) ;
InitialElement := TRUE ;
ForeachNodeDo(Aliases, DescribeElement) ;
Output.WriteLn ;
Indent := 3 ;
IndentString('ELSE') ; Output.WriteLn ;
IndentString('END ;') ; Output.WriteLn ;
IndentString('') ;
Output.WriteKey(ErrorProcString) ; Output.WriteString('(str) ;') ; Output.WriteLn ;
Indent := 0 ;
IndentString('END DescribeError ;') ; Output.WriteLn
END EmitDescribeError ;
(*
EmitSetTypes - write out the set types used during error recovery
*)
PROCEDURE EmitSetTypes ;
VAR
i, j, m, n: CARDINAL ;
BEGIN
Output.WriteString('(*') ; NewLine(3) ;
Output.WriteString('expecting token set defined as an enumerated type') ; NewLine(3) ;
Output.WriteString('(') ;
i := 0 ;
WHILE i<LargestValue DO
Output.WriteKey(GetSymKey(ReverseValues, WORD(i))) ;
INC(i) ;
IF i<LargestValue
THEN
Output.WriteString(', ')
END
END ;
Output.WriteString(') ;') ; NewLine(0) ;
Output.WriteString('*)') ; NewLine(0) ;
Output.WriteString('TYPE') ; NewLine(3) ;
IF LargestValue>MaxElementsInSet
THEN
i := 0 ;
n := LargestValue DIV MaxElementsInSet ;
WHILE i<=n DO
j := (i*MaxElementsInSet) ;
IF LargestValue<(i+1)*MaxElementsInSet-1
THEN
m := LargestValue-1
ELSE
m := (i+1)*MaxElementsInSet-1
END ;
Output.WriteString('stop') ; Output.WriteCard(i, 0) ;
Output.WriteString(' = [') ;
Output.WriteKey(GetSymKey(ReverseValues, WORD(j))) ;
Output.WriteString('..') ;
Output.WriteKey(GetSymKey(ReverseValues, WORD(m))) ;
Output.WriteString('] ;') ;
NewLine(3) ;
Output.WriteString('SetOfStop') ; Output.WriteCard(i, 0) ;
Output.WriteString(' = SET OF stop') ; Output.WriteCard(i, 0) ;
Output.WriteString(' ;') ;
NewLine(3) ;
INC(i)
END
ELSE
Output.WriteString('SetOfStop') ;
Output.WriteString(' = SET OF [') ;
Output.WriteKey(GetSymKey(ReverseValues, WORD(0))) ;
Output.WriteString('..') ;
Output.WriteKey(GetSymKey(ReverseValues, WORD(LargestValue-1))) ;
Output.WriteString('] ;')
END ;
NewLine(0)
END EmitSetTypes ;
(*
EmitSupport - generates the support routines.
*)
PROCEDURE EmitSupport ;
BEGIN
IF ErrorRecovery
THEN
EmitSetTypes ;
EmitDescribeStop ;
EmitDescribeError
END
END EmitSupport ;
(*
DisposeSetDesc - dispose of the set list, s.
*)
PROCEDURE DisposeSetDesc (VAR s: SetDesc) ;
VAR
h, n: SetDesc ;
BEGIN
IF s#NIL
THEN
h := s ;
n := s^.next ;
REPEAT
DISPOSE(h) ;
h := n ;
IF n#NIL
THEN
n := n^.next
END
UNTIL h=NIL ;
s := NIL
END
END DisposeSetDesc ;
(*
OptionalFactor -
*)
PROCEDURE OptionalFactor (f: FactorDesc) : BOOLEAN ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : |
lit : |
sub ,
opt ,
mult: IF OptionalExpression(expr)
THEN
RETURN( TRUE )
END |
m2 :
ELSE
END
END ;
f := f^.next
END ;
RETURN( FALSE )
END OptionalFactor ;
(*
OptionalTerm - returns TRUE if the term maybe empty.
*)
PROCEDURE OptionalTerm (t: TermDesc) : BOOLEAN ;
VAR
u, v : TermDesc ;
tov, tou: SetDesc ;
BEGIN
u := t ;
WHILE u#NIL DO
IF OptionalFactor(u^.factor)
THEN
RETURN( TRUE )
END ;
v := t ;
tou := NIL ;
CalcFirstFactor(u^.factor, NIL, tou) ;
WHILE v#NIL DO
IF v#u
THEN
tov := NIL ;
CalcFirstFactor(v^.factor, NIL, tov) ;
IF IntersectionIsNil(tov, tou)
THEN
DisposeSetDesc(tov) ;
ELSE
WriteString('problem with two first sets. Set 1: ') ;
EmitSet(tou, 0, 0) ; WriteLn ;
WriteString(' Set 2: ') ;
EmitSet(tov, 0, 0) ; WriteLn ;
DisposeSetDesc(tou) ;
DisposeSetDesc(tov) ;
RETURN( TRUE )
END
END ;
v := v^.next
END ;
DisposeSetDesc(tou) ;
u := u^.next
END ;
RETURN( FALSE )
END OptionalTerm ;
(*
OptionalExpression -
*)
PROCEDURE OptionalExpression (e: ExpressionDesc) : BOOLEAN ;
BEGIN
IF e=NIL
THEN
RETURN( FALSE )
ELSE
RETURN( OptionalTerm(e^.term) )
END
END OptionalExpression ;
(*
OptionalStatement - returns FALSE if statement, s, does not have a optional ambiguity.
*)
PROCEDURE OptionalStatement (s: StatementDesc) : BOOLEAN ;
BEGIN
IF s=NIL
THEN
RETURN( FALSE )
ELSE
RETURN( OptionalExpression(s^.expr) )
END
END OptionalStatement ;
(*
OptionalProduction -
*)
PROCEDURE OptionalProduction (p: ProductionDesc) : BOOLEAN ;
BEGIN
IF p=NIL
THEN
RETURN( FALSE )
ELSE
RETURN( OptionalStatement(p^.statement) )
END
END OptionalProduction ;
(*
CheckFirstFollow -
*)
PROCEDURE CheckFirstFollow (f: FactorDesc; after: FactorDesc) : BOOLEAN ;
VAR
first, follow: SetDesc ;
BEGIN
first := NIL ;
CalcFirstFactor(f, NIL, first) ;
follow := NIL ;
follow := GetFollow(f^.followinfo) ;
IF IntersectionIsNil(first, follow)
THEN
DisposeSetDesc(first) ;
DisposeSetDesc(follow) ;
RETURN( FALSE )
ELSE
PrettyCommentFactor(f, 3) ;
NewLine(3) ;
WriteString('first: ') ;
EmitSet(first, 0, 0) ;
NewLine(3) ;
WriteString('follow: ') ;
EmitSet(follow, 0, 0) ;
NewLine(3) ;
DisposeSetDesc(first) ;
DisposeSetDesc(follow) ;
RETURN( TRUE )
END
END CheckFirstFollow ;
(*
ConstrainedEmptyFactor -
*)
PROCEDURE ConstrainedEmptyFactor (f: FactorDesc) : BOOLEAN ;
BEGIN
WHILE f#NIL DO
WITH f^ DO
CASE type OF
id : |
lit : |
sub ,
opt ,
mult: IF ConstrainedEmptyExpression(expr)
THEN
RETURN( TRUE )
END |
m2 :
ELSE
END
END ;
IF (f^.type#m2) AND EmptyFactor(f) AND CheckFirstFollow(f, f^.next)
THEN
RETURN( TRUE )
END ;
f := f^.next
END ;
RETURN( FALSE )
END ConstrainedEmptyFactor ;
(*
ConstrainedEmptyTerm - returns TRUE if the term maybe empty.
*)
PROCEDURE ConstrainedEmptyTerm (t: TermDesc) : BOOLEAN ;
VAR
first, follow: SetDesc ;
BEGIN
WHILE t#NIL DO
IF ConstrainedEmptyFactor(t^.factor)
THEN
RETURN( TRUE )
ELSIF (t^.factor^.type#m2) AND EmptyFactor(t^.factor) AND CheckFirstFollow(t^.factor, t^.factor^.next)
THEN
RETURN( TRUE )
END ;
t := t^.next
END ;
RETURN( FALSE )
END ConstrainedEmptyTerm ;
(*
ConstrainedEmptyExpression -
*)
PROCEDURE ConstrainedEmptyExpression (e: ExpressionDesc) : BOOLEAN ;
BEGIN
IF e=NIL
THEN
RETURN( FALSE )
ELSE
RETURN( ConstrainedEmptyTerm(e^.term) )
END
END ConstrainedEmptyExpression ;
(*
ConstrainedEmptyStatement - returns FALSE if statement, s, does not have a optional ambiguity.
*)
PROCEDURE ConstrainedEmptyStatement (s: StatementDesc) : BOOLEAN ;
BEGIN
IF s=NIL
THEN
RETURN( FALSE )
ELSE
RETURN( ConstrainedEmptyExpression(s^.expr) )
END
END ConstrainedEmptyStatement ;
(*
ConstrainedEmptyProduction - returns TRUE if a problem exists with, p.
*)
PROCEDURE ConstrainedEmptyProduction (p: ProductionDesc) : BOOLEAN ;
BEGIN
IF p=NIL
THEN
RETURN( FALSE )
ELSE
RETURN( ConstrainedEmptyStatement(p^.statement) )
END
END ConstrainedEmptyProduction ;
(*
TestForLALR1 -
*)
PROCEDURE TestForLALR1 (p: ProductionDesc) ;
BEGIN
IF OptionalProduction(p)
THEN
WarnError1('production %s has two optional sentances using | which both have the same start symbols',
p^.statement^.ident^.name) ;
WasNoError := FALSE ;
PrettyCommentProduction(p)
END ;
(*
IF ConstrainedEmptyProduction(p)
THEN
WarnError1('production %s has an empty sentance and the first and follow symbols intersect',
p^.statement^.ident^.name) ;
WasNoError := FALSE
END
*)
END TestForLALR1 ;
(*
DoEpsilon - runs the epsilon interrelated rules
*)
PROCEDURE DoEpsilon (p: ProductionDesc) ;
BEGIN
CalcEpsilonProduction(p) ;
CalcReachEndProduction(p)
END DoEpsilon ;
(*
CheckComplete - checks that production, p, is complete.
*)
PROCEDURE CheckComplete (p: ProductionDesc) ;
BEGIN
IF GetReachEnd(p^.followinfo)=unknown
THEN
PrettyCommentProduction(p) ;
WarnError1('cannot determine epsilon, probably a left recursive rule in %s and associated rules (hint rewrite using ebnf and eliminate left recursion)',
p^.statement^.ident^.name) ;
WasNoError := FALSE
END
END CheckComplete ;
(*
PostProcessRules - backpatch the ident to rule definitions and emit comments and code.
*)
PROCEDURE PostProcessRules ;
BEGIN
ForeachRuleDo(BackPatchIdentToDefinitions) ;
IF NOT WasNoError
THEN
HALT
END ;
WhileNotCompleteDo(DoEpsilon) ;
IF NOT WasNoError
THEN
HALT
END ;
ForeachRuleDo(CheckComplete) ;
IF NOT WasNoError
THEN
HALT
END ;
WhileNotCompleteDo(CalculateFirstAndFollow) ;
IF NOT WasNoError
THEN
HALT
END ;
ForeachRuleDo(TestForLALR1) ;
IF NOT WasNoError
THEN
ForeachRuleDo(PrettyCommentProduction)
END
END PostProcessRules ;
(*
DisplayHelp - display a summary help and then exit (0).
*)
PROCEDURE DisplayHelp ;
BEGIN
WriteString('Usage: ppg [-l] [-c] [-d] [-e] [-k] [-t] [-k] [-p] [-x] [-f] [-o outputfile] filename') ; WriteLn ;
WriteString(' -l suppress file and line source information') ; WriteLn ;
WriteString(' -c do not generate any Modula-2 code within the parser rules') ; WriteLn ;
WriteString(' -h or --help generate this help message') ; WriteLn ;
WriteString(' -e do not generate a parser with error recovery') ; WriteLn ;
WriteString(' -k generate keyword errors with GCC formatting directives') ; WriteLn ;
WriteString(' -d generate internal debugging information') ; WriteLn ;
WriteString(' -p only display the ebnf rules') ; WriteLn ;
WriteString(' -t generate texinfo formating for pretty printing (-p)') ; WriteLn ;
WriteString(' -x generate sphinx formating for pretty printing (-p)') ; WriteLn ;
WriteString(' -f generate GNU Free Documentation header before pretty printing in texinfo') ; WriteLn ;
WriteString(' -o write output to filename') ; WriteLn ;
exit (0)
END DisplayHelp ;
(*
ParseArgs -
*)
PROCEDURE ParseArgs ;
VAR
n, i: CARDINAL ;
BEGIN
ErrorRecovery := TRUE ; (* DefaultRecovery ; *)
Debugging := FALSE ;
PrettyPrint := FALSE ;
KeywordFormatting := FALSE ;
i := 1 ;
n := Narg() ;
WHILE i<n DO
IF GetArg(ArgName, i)
THEN
IF StrEqual(ArgName, '-e')
THEN
ErrorRecovery := FALSE
ELSIF StrEqual(ArgName, '-d')
THEN
Debugging := TRUE ;
SetDebugging(TRUE)
ELSIF StrEqual(ArgName, '-c')
THEN
EmitCode := FALSE
ELSIF StrEqual(ArgName, '-k')
THEN
KeywordFormatting := TRUE
ELSIF StrEqual(ArgName, '-l')
THEN
SuppressFileLineTag := TRUE
ELSIF StrEqual(ArgName, '-h') OR StrEqual(ArgName, '--help')
THEN
DisplayHelp
ELSIF StrEqual(ArgName, '-p')
THEN
PrettyPrint := TRUE
ELSIF StrEqual(ArgName, '-t')
THEN
Texinfo := TRUE
ELSIF StrEqual(ArgName, '-x')
THEN
Sphinx := TRUE
ELSIF StrEqual(ArgName, '-f')
THEN
FreeDocLicense := TRUE
ELSIF StrEqual(ArgName, '-o')
THEN
INC (i) ;
IF GetArg(ArgName, i)
THEN
IF NOT Output.Open (ArgName)
THEN
WriteString('cannot open ') ; WriteString(ArgName) ;
WriteString(' for writing') ; WriteLn ;
exit (1)
END
END
ELSIF OpenSource(ArgName)
THEN
StrCopy (ArgName, FileName) ;
AdvanceToken
ELSE
WriteString('cannot open ') ; WriteString(ArgName) ;
WriteString(' for reading') ; WriteLn ;
exit (1)
END
END ;
INC (i)
END ;
IF n=1
THEN
DisplayHelp
END
END ParseArgs ;
(*
Init - initialize the modules data structures
*)
PROCEDURE Init ;
BEGIN
WasNoError := TRUE ;
Texinfo := FALSE ;
Sphinx := FALSE ;
FreeDocLicense := FALSE ;
EmitCode := TRUE ;
LargestValue := 0 ;
HeadProduction := NIL ;
CurrentProduction := NIL ;
InitTree(Aliases) ;
InitTree(ReverseAliases) ;
InitTree(Values) ;
InitTree(ReverseValues) ;
LastLineNo := 0 ;
CodePrologue := NIL ;
CodeEpilogue := NIL ;
CodeDeclaration := NIL ;
ErrorProcArray := MakeKey('Error') ;
ErrorProcString := MakeKey('ErrorS') ;
TokenTypeProc := MakeKey('GetCurrentTokenType()') ;
SymIsProc := MakeKey('SymIs') ;
OnLineStart := TRUE ;
ParseArgs ;
WasNoError := Main() ; (* this line will be manipulated by sed in buildpg *)
IF WasNoError
THEN
PostProcessRules ;
IF WasNoError
THEN
IF Debugging
THEN
EmitRules
ELSIF PrettyPrint
THEN
EmitRules
ELSE
Output.WriteString('(* it is advisable not to edit this file as it was automatically generated from the grammer file ') ;
Output.WriteString(FileName) ; Output.WriteString(' *)') ; Output.WriteLn ;
OnLineStart := FALSE ;
EmitFileLineTag(LinePrologue) ;
BeginningOfLine := TRUE ;
WriteCodeHunkList(CodePrologue) ;
EmitSupport ;
EmitFileLineTag(LineDeclaration) ;
WriteCodeHunkList(CodeDeclaration) ;
EmitRules ;
(* code rules *)
EmitFileLineTag(LineEpilogue) ;
WriteCodeHunkList(CodeEpilogue)
END
END
END ;
Output.Close
END Init ;
BEGIN
Init
END ppg.
(*
* Local variables:
* compile-command: "gm2 -I../gm2-libs:. -fbounds -freturn -c -g ppg.mod"
* End:
*)