Google Git
Sign in
gnu / gcc / refs/tags/basepoints/gcc-13 / . / gcc / ada / scng.adb
blob: d0fb7f1c1f62ef1901d5e229181aa72814fbaa48 [file] [log] [blame]
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S C N G --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2022, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT 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 distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Atree; use Atree;
with Csets; use Csets;
with Errout; use Errout;
with Hostparm; use Hostparm;
with Namet; use Namet;
with Opt; use Opt;
with Scans; use Scans;
with Sinput; use Sinput;
with Snames; use Snames;
with Stringt; use Stringt;
with Stylesw; use Stylesw;
with Uintp; use Uintp;
with Urealp; use Urealp;
with Widechar; use Widechar;
pragma Warnings (Off);
-- This package is used also by gnatcoll
with System.CRC32;
with System.UTF_32; use System.UTF_32;
with System.WCh_Con; use System.WCh_Con;
pragma Warnings (On);
package body Scng is
use ASCII;
-- Make control characters visible
Special_Characters : array (Character) of Boolean := (others => False);
-- For characters that are Special token, the value is True
Comment_Is_Token : Boolean := False;
-- True if comments are tokens
End_Of_Line_Is_Token : Boolean := False;
-- True if End_Of_Line is a token
-----------------------
-- Local Subprograms --
-----------------------
procedure Accumulate_Token_Checksum;
pragma Inline (Accumulate_Token_Checksum);
-- Called after each numeric literal and identifier/keyword. For keywords,
-- the token used is Tok_Identifier. This allows detection of additional
-- spaces added in sources when using the builder switch -m.
procedure Accumulate_Checksum (C : Character);
pragma Inline (Accumulate_Checksum);
-- This routine accumulates the checksum given character C. During the
-- scanning of a source file, this routine is called with every character
-- in the source, excluding blanks, and all control characters (except
-- that ESC is included in the checksum). Upper case letters not in string
-- literals are folded by the caller. See Sinput spec for the documentation
-- of the checksum algorithm. Note: checksum values are only used if we
-- generate code, so it is not necessary to worry about making the right
-- sequence of calls in any error situation.
procedure Accumulate_Checksum (C : Char_Code);
pragma Inline (Accumulate_Checksum);
-- This version is identical, except that the argument, C, is a character
-- code value instead of a character. This is used when wide characters
-- are scanned. We use the character code rather than the ASCII characters
-- so that the checksum is independent of wide character encoding method.
procedure Initialize_Checksum;
pragma Inline (Initialize_Checksum);
-- Initialize checksum value
-------------------------
-- Accumulate_Checksum --
-------------------------
procedure Accumulate_Checksum (C : Character) is
begin
System.CRC32.Update (System.CRC32.CRC32 (Checksum), C);
end Accumulate_Checksum;
procedure Accumulate_Checksum (C : Char_Code) is
begin
if C > 16#FFFF# then
Accumulate_Checksum (Character'Val (C / 2 ** 24));
Accumulate_Checksum (Character'Val ((C / 2 ** 16) mod 256));
Accumulate_Checksum (Character'Val ((C / 256) mod 256));
else
Accumulate_Checksum (Character'Val (C / 256));
end if;
Accumulate_Checksum (Character'Val (C mod 256));
end Accumulate_Checksum;
-------------------------------
-- Accumulate_Token_Checksum --
-------------------------------
procedure Accumulate_Token_Checksum is
begin
System.CRC32.Update
(System.CRC32.CRC32 (Checksum),
Character'Val (Token_Type'Pos (Token)));
end Accumulate_Token_Checksum;
-----------------------
-- Check_End_Of_Line --
-----------------------
procedure Check_End_Of_Line is
Len : constant Int :=
Int (Scan_Ptr) -
Int (Current_Line_Start) -
Wide_Char_Byte_Count;
-- Start of processing for Check_End_Of_Line
begin
if Style_Check then
Style.Check_Line_Terminator (Len);
end if;
-- Deal with checking maximum line length
if Style_Check and Style_Check_Max_Line_Length then
Style.Check_Line_Max_Length (Len);
-- If style checking is inactive, check maximum line length against
-- standard value.
elsif Len > Max_Line_Length then
Error_Msg
("this line is too long",
Current_Line_Start + Source_Ptr (Max_Line_Length));
end if;
-- Now one more checking circuit. Normally we are only enforcing a limit
-- of physical characters, with tabs counting as one character. But if
-- after tab expansion we would have a total line length that exceeded
-- 32766, that would really cause trouble, because column positions
-- would exceed the maximum we allow for a column count. Note: the limit
-- is 32766 rather than 32767, since we use a value of 32767 for special
-- purposes (see Sinput). Now we really do not want to go messing with
-- tabs in the normal case, so what we do is to check for a line that
-- has more than 4096 physical characters. Any shorter line could not
-- be a problem, even if it was all tabs.
if Len >= 4096 then
declare
Col : Natural;
Ptr : Source_Ptr;
begin
Col := 1;
Ptr := Current_Line_Start;
loop
exit when Ptr = Scan_Ptr;
if Source (Ptr) = ASCII.HT then
Col := (Col - 1 + 8) / 8 * 8 + 1;
else
Col := Col + 1;
end if;
if Col > 32766 then
Error_Msg
("this line is longer than 32766 characters",
Current_Line_Start);
raise Unrecoverable_Error;
end if;
Ptr := Ptr + 1;
end loop;
end;
end if;
-- Reset wide character byte count for next line
Wide_Char_Byte_Count := 0;
end Check_End_Of_Line;
----------------------------
-- Determine_Token_Casing --
----------------------------
function Determine_Token_Casing return Casing_Type is
begin
return Determine_Casing (Source (Token_Ptr .. Scan_Ptr - 1));
end Determine_Token_Casing;
-------------------------
-- Initialize_Checksum --
-------------------------
procedure Initialize_Checksum is
begin
System.CRC32.Initialize (System.CRC32.CRC32 (Checksum));
end Initialize_Checksum;
------------------------
-- Initialize_Scanner --
------------------------
procedure Initialize_Scanner (Index : Source_File_Index) is
begin
-- Establish reserved words
Scans.Initialize_Ada_Keywords;
-- Initialize scan control variables
Current_Source_File := Index;
Source := Source_Text (Current_Source_File);
Scan_Ptr := Source_First (Current_Source_File);
Token := No_Token;
Token_Ptr := Scan_Ptr;
Current_Line_Start := Scan_Ptr;
Token_Node := Empty;
Token_Name := No_Name;
Start_Column := Set_Start_Column;
First_Non_Blank_Location := Scan_Ptr;
Initialize_Checksum;
Wide_Char_Byte_Count := 0;
-- Do not call Scan, otherwise the License stuff does not work in Scn
end Initialize_Scanner;
------------------------------
-- Reset_Special_Characters --
------------------------------
procedure Reset_Special_Characters is
begin
Special_Characters := (others => False);
end Reset_Special_Characters;
----------
-- Scan --
----------
procedure Scan is
Start_Of_Comment : Source_Ptr;
-- Record start of comment position
Underline_Found : Boolean;
-- During scanning of an identifier, set to True if last character
-- scanned was an underline or other punctuation character. This
-- is used to flag the error of two underlines/punctuations in a
-- row or ending an identifier with a underline/punctuation. Here
-- punctuation means any UTF_32 character in the Unicode category
-- Punctuation,Connector.
Wptr : Source_Ptr;
-- Used to remember start of last wide character scanned
function Double_Char_Token (C : Character) return Boolean;
-- This function is used for double character tokens like := or <>. It
-- checks if the character following Source (Scan_Ptr) is C, and if so
-- bumps Scan_Ptr past the pair of characters and returns True. A space
-- between the two characters is also recognized with an appropriate
-- error message being issued. If C is not present, False is returned.
-- Note that Double_Char_Token can only be used for tokens defined in
-- the Ada syntax (it's use for error cases like && is not appropriate
-- since we do not want a junk message for a case like &-space-&).
procedure Error_Illegal_Character;
-- Give illegal character error, Scan_Ptr points to character. On
-- return, Scan_Ptr is bumped past the illegal character.
procedure Error_Illegal_Wide_Character;
-- Give illegal wide character message. On return, Scan_Ptr is bumped
-- past the illegal character, which may still leave us pointing to
-- junk, not much we can do if the escape sequence is messed up.
procedure Error_No_Double_Underline;
-- Signal error of two underline or punctuation characters in a row.
-- Called with Scan_Ptr pointing to second underline/punctuation char.
procedure Nlit;
-- This is the procedure for scanning out numeric literals. On entry,
-- Scan_Ptr points to the digit that starts the numeric literal (the
-- checksum for this character has not been accumulated yet). On return
-- Scan_Ptr points past the last character of the numeric literal, Token
-- and Token_Node are set appropriately, and the checksum is updated.
procedure Slit;
-- This is the procedure for scanning out string literals. On entry,
-- Scan_Ptr points to the opening string quote (the checksum for this
-- character has not been accumulated yet). On return Scan_Ptr points
-- past the closing quote of the string literal, Token and Token_Node
-- are set appropriately, and the checksum is updated.
procedure Skip_Other_Format_Characters;
-- Skips past any "other format" category characters at the current
-- cursor location (does not skip past spaces or any other characters).
function Start_Of_Wide_Character return Boolean;
-- Returns True if the scan pointer is pointing to the start of a wide
-- character sequence, does not modify the scan pointer in any case.
procedure Check_Bidi (Code : Char_Code);
-- Give a warning if Code is a bidirectional character, which can cause
-- security vulnerabilities. See the following article:
--
-- @article{boucher_trojansource_2021,
-- title = {Trojan {Source}: {Invisible} {Vulnerabilities}},
-- author = {Nicholas Boucher and Ross Anderson},
-- year = {2021},
-- journal = {Preprint},
-- eprint = {2111.00169},
-- archivePrefix = {arXiv},
-- primaryClass = {cs.CR},
-- url = {https://arxiv.org/abs/2111.00169}
-- }
----------------
-- Check_Bidi --
----------------
type Bidi_Characters is
(LRE, RLE, LRO, RLO, LRI, RLI, FSI, PDF, PDI);
Bidi_Character_Codes : constant array (Bidi_Characters) of Char_Code :=
(LRE => 16#202A#,
RLE => 16#202B#,
LRO => 16#202D#,
RLO => 16#202E#,
LRI => 16#2066#,
RLI => 16#2067#,
FSI => 16#2068#,
PDF => 16#202C#,
PDI => 16#2069#);
-- Above are the bidirectional characters, along with their Unicode code
-- points.
procedure Check_Bidi (Code : Char_Code) is
begin
for Bidi_Code of Bidi_Character_Codes loop
if Code = Bidi_Code then
Error_Msg ("??bidirectional wide character", Wptr);
end if;
end loop;
end Check_Bidi;
-----------------------
-- Double_Char_Token --
-----------------------
function Double_Char_Token (C : Character) return Boolean is
begin
if Source (Scan_Ptr + 1) = C then
Accumulate_Checksum (C);
Scan_Ptr := Scan_Ptr + 2;
return True;
elsif Source (Scan_Ptr + 1) = ' '
and then Source (Scan_Ptr + 2) = C
then
Scan_Ptr := Scan_Ptr + 1;
Error_Msg_S -- CODEFIX
("no space allowed here");
Scan_Ptr := Scan_Ptr + 2;
return True;
else
return False;
end if;
end Double_Char_Token;
-----------------------------
-- Error_Illegal_Character --
-----------------------------
procedure Error_Illegal_Character is
begin
Error_Msg_S ("illegal character");
Scan_Ptr := Scan_Ptr + 1;
end Error_Illegal_Character;
----------------------------------
-- Error_Illegal_Wide_Character --
----------------------------------
procedure Error_Illegal_Wide_Character is
begin
Scan_Ptr := Scan_Ptr + 1;
Error_Msg ("illegal wide character", Wptr);
end Error_Illegal_Wide_Character;
-------------------------------
-- Error_No_Double_Underline --
-------------------------------
procedure Error_No_Double_Underline is
begin
Underline_Found := False;
-- There are four cases, and we special case the messages
if Source (Scan_Ptr) = '_' then
if Source (Scan_Ptr - 1) = '_' then
Error_Msg_S -- CODEFIX
("two consecutive underlines not permitted");
else
Error_Msg_S ("underline cannot follow punctuation character");
end if;
else
if Source (Scan_Ptr - 1) = '_' then
Error_Msg_S ("punctuation character cannot follow underline");
else
Error_Msg_S
("two consecutive punctuation characters not permitted");
end if;
end if;
end Error_No_Double_Underline;
----------
-- Nlit --
----------
procedure Nlit is
C : Character;
-- Current source program character
Base_Char : Character;
-- Either # or : (character at start of based number)
Base : Int;
-- Value of base
UI_Base : Uint;
-- Value of base in Uint format
UI_Int_Value : Uint;
-- Value of integer scanned by Scan_Integer in Uint format
UI_Num_Value : Uint;
-- Value of integer in numeric value being scanned
Scale : Int;
-- Scale value for real literal
UI_Scale : Uint;
-- Scale in Uint format
Exponent_Is_Negative : Boolean;
-- Set true for negative exponent
Extended_Digit_Value : Int;
-- Extended digit value
Point_Scanned : Boolean;
-- Flag for decimal point scanned in numeric literal
-----------------------
-- Local Subprograms --
-----------------------
procedure Error_Digit_Expected;
-- Signal error of bad digit, Scan_Ptr points to the location at
-- which the digit was expected on input, and is unchanged on return.
procedure Scan_Integer;
-- Scan integer literal. On entry, Scan_Ptr points to a digit, on
-- exit Scan_Ptr points past the last character of the integer.
--
-- For each digit encountered, UI_Int_Value is multiplied by 10, and
-- the value of the digit added to the result. In addition, the value
-- in Scale is decremented by one for each actual digit scanned.
--------------------------
-- Error_Digit_Expected --
--------------------------
procedure Error_Digit_Expected is
begin
Error_Msg_S ("digit expected");
end Error_Digit_Expected;
------------------
-- Scan_Integer --
------------------
procedure Scan_Integer is
C : Character;
-- Next character scanned
begin
C := Source (Scan_Ptr);
-- Loop through digits (allowing underlines)
loop
Accumulate_Checksum (C);
UI_Int_Value :=
UI_Int_Value * 10 + (Character'Pos (C) - Character'Pos ('0'));
Scan_Ptr := Scan_Ptr + 1;
Scale := Scale - 1;
C := Source (Scan_Ptr);
-- Case of underline encountered
if C = '_' then
-- We do not accumulate the '_' in the checksum, so that
-- 1_234 is equivalent to 1234, and does not trigger
-- compilation for "minimal recompilation" (gnatmake -m).
loop
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
exit when C /= '_';
Error_No_Double_Underline;
end loop;
if C not in '0' .. '9' then
Error_Digit_Expected;
exit;
end if;
else
exit when C not in '0' .. '9';
end if;
end loop;
end Scan_Integer;
-- Start of processing for Nlit
begin
Base := 10;
UI_Base := Uint_10;
UI_Int_Value := Uint_0;
Based_Literal_Uses_Colon := False;
Scale := 0;
Scan_Integer;
Point_Scanned := False;
UI_Num_Value := UI_Int_Value;
-- Various possibilities now for continuing the literal are period,
-- E/e (for exponent), or :/# (for based literal).
Scale := 0;
C := Source (Scan_Ptr);
if C = '.' then
-- Scan out point, but do not scan past .. which is a range
-- sequence, and must not be eaten up scanning a numeric literal.
while C = '.' and then Source (Scan_Ptr + 1) /= '.' loop
Accumulate_Checksum ('.');
if Point_Scanned then
Error_Msg_S ("duplicate point ignored");
end if;
Point_Scanned := True;
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
if C not in '0' .. '9' then
Error_Msg
("real literal cannot end with point", Scan_Ptr - 1);
else
Scan_Integer;
UI_Num_Value := UI_Int_Value;
end if;
end loop;
-- Based literal case. The base is the value we already scanned.
-- In the case of colon, we insist that the following character
-- is indeed an extended digit or a period. This catches a number
-- of common errors, as well as catching the well known tricky
-- bug otherwise arising from "x : integer range 1 .. 10:= 6;"
elsif C = '#'
or else (C = ':' and then
(Source (Scan_Ptr + 1) = '.'
or else
Source (Scan_Ptr + 1) in '0' .. '9'
or else
Source (Scan_Ptr + 1) in 'A' .. 'Z'
or else
Source (Scan_Ptr + 1) in 'a' .. 'z'))
then
Accumulate_Checksum (C);
Base_Char := C;
UI_Base := UI_Int_Value;
if Base_Char = ':' then
Based_Literal_Uses_Colon := True;
end if;
if UI_Base < 2 or else UI_Base > 16 then
Error_Msg_SC ("base not 2-16");
UI_Base := Uint_16;
end if;
Base := UI_To_Int (UI_Base);
Scan_Ptr := Scan_Ptr + 1;
-- Scan out extended integer [. integer]
C := Source (Scan_Ptr);
UI_Int_Value := Uint_0;
Scale := 0;
loop
if C in '0' .. '9' then
Accumulate_Checksum (C);
Extended_Digit_Value :=
Int'(Character'Pos (C)) - Int'(Character'Pos ('0'));
elsif C in 'A' .. 'F' then
Accumulate_Checksum (Character'Val (Character'Pos (C) + 32));
Extended_Digit_Value :=
Int'(Character'Pos (C)) - Int'(Character'Pos ('A')) + 10;
elsif C in 'a' .. 'f' then
Accumulate_Checksum (C);
Extended_Digit_Value :=
Int'(Character'Pos (C)) - Int'(Character'Pos ('a')) + 10;
else
Error_Msg_S ("extended digit expected");
exit;
end if;
if Extended_Digit_Value >= Base then
Error_Msg_S ("digit '>= base");
end if;
UI_Int_Value := UI_Int_Value * UI_Base + Extended_Digit_Value;
Scale := Scale - 1;
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
if C = '_' then
loop
Accumulate_Checksum ('_');
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
exit when C /= '_';
Error_No_Double_Underline;
end loop;
elsif C = '.' then
Accumulate_Checksum ('.');
if Point_Scanned then
Error_Msg_S ("duplicate point ignored");
end if;
Scan_Ptr := Scan_Ptr + 1;
C := Source (Scan_Ptr);
Point_Scanned := True;
Scale := 0;
elsif C = Base_Char then
Accumulate_Checksum (C);
Scan_Ptr := Scan_Ptr + 1;
exit;
elsif C = '#' or else C = ':' then
Error_Msg_S ("based number delimiters must match");
Scan_Ptr := Scan_Ptr + 1;
exit;
elsif not Identifier_Char (C) then
if Base_Char = '#' then
Error_Msg_S -- CODEFIX
("missing '#");
else
Error_Msg_S -- CODEFIX
("missing ':");
end if;
exit;
end if;
end loop;
UI_Num_Value := UI_Int_Value;
end if;
-- Scan out exponent
if not Point_Scanned then
Scale := 0;
UI_Scale := Uint_0;
else
UI_Scale := UI_From_Int (Scale);
end if;
if Source (Scan_Ptr) = 'e' or else Source (Scan_Ptr) = 'E' then
Accumulate_Checksum ('e');
Scan_Ptr := Scan_Ptr + 1;
Exponent_Is_Negative := False;
if Source (Scan_Ptr) = '+' then
Accumulate_Checksum ('+');
Scan_Ptr := Scan_Ptr + 1;
elsif Source (Scan_Ptr) = '-' then
Accumulate_Checksum ('-');
if not Point_Scanned then
Error_Msg_S
("negative exponent not allowed for integer literal");
else
Exponent_Is_Negative := True;
end if;
Scan_Ptr := Scan_Ptr + 1;
end if;
UI_Int_Value := Uint_0;
if Source (Scan_Ptr) in '0' .. '9' then
Scan_Integer;
else
Error_Digit_Expected;
end if;
if Exponent_Is_Negative then
UI_Scale := UI_Scale - UI_Int_Value;
else
UI_Scale := UI_Scale + UI_Int_Value;
end if;
end if;
-- Case of real literal to be returned
if Point_Scanned then
Token := Tok_Real_Literal;
Real_Literal_Value :=
UR_From_Components (
Num => UI_Num_Value,
Den => -UI_Scale,
Rbase => Base);
-- Case of integer literal to be returned
else
Token := Tok_Integer_Literal;
if UI_Scale = 0 then
Int_Literal_Value := UI_Num_Value;
-- Avoid doing possibly expensive calculations in cases like
-- parsing 163E800_000# when semantics will not be done anyway.
-- This is especially useful when parsing garbled input.
elsif Operating_Mode /= Check_Syntax
and then (Serious_Errors_Detected = 0 or else Try_Semantics)
then
Int_Literal_Value := UI_Num_Value * UI_Base ** UI_Scale;
else
Int_Literal_Value := No_Uint;
end if;
end if;
Accumulate_Token_Checksum;
end Nlit;
----------
-- Slit --
----------
procedure Slit is
Delimiter : Character;
-- Delimiter (first character of string)
C : Character;
-- Current source program character
Code : Char_Code;
-- Current character code value
Err : Boolean;
-- Error flag for Scan_Wide call
String_Start : Source_Ptr;
-- Point to first character of string
procedure Error_Bad_String_Char;
-- Signal bad character in string/character literal. On entry
-- Scan_Ptr points to the improper character encountered during the
-- scan. Scan_Ptr is not modified, so it still points to the bad
-- character on return.
procedure Error_Unterminated_String;
-- Procedure called if a line terminator character is encountered
-- during scanning a string, meaning that the string is not properly
-- terminated.
procedure Set_String;
-- Procedure used to distinguish between string and operator symbol.
-- On entry the string has been scanned out, and its characters start
-- at Token_Ptr and end one character before Scan_Ptr. On exit Token
-- is set to Tok_String_Literal/Tok_Operator_Symbol as appropriate,
-- and Token_Node is appropriately initialized. In addition, in the
-- operator symbol case, Token_Name is appropriately set, and the
-- flags [Wide_]Wide_Character_Found are set appropriately.
---------------------------
-- Error_Bad_String_Char --
---------------------------
procedure Error_Bad_String_Char is
C : constant Character := Source (Scan_Ptr);
begin
if C = HT then
Error_Msg_S ("horizontal tab not allowed in string");
elsif C = VT or else C = FF then
Error_Msg_S ("format effector not allowed in string");
elsif C in Upper_Half_Character then
Error_Msg_S ("(Ada 83) upper half character not allowed");
else
Error_Msg_S ("control character not allowed in string");
end if;
end Error_Bad_String_Char;
-------------------------------
-- Error_Unterminated_String --
-------------------------------
procedure Error_Unterminated_String is
S : Source_Ptr;
begin
-- An interesting little refinement. Consider the following
-- examples:
-- A := "this is an unterminated string;
-- A := "this is an unterminated string &
-- P(A, "this is a parameter that didn't get terminated);
-- P("this is a parameter that didn't get terminated, A);
-- We fiddle a little to do slightly better placement in these
-- cases also if there is white space at the end of the line we
-- place the flag at the start of this white space, not at the
-- end. Note that we only have to test for blanks, since tabs
-- aren't allowed in strings in the first place and would have
-- caused an error message.
-- Two more cases that we treat specially are:
-- A := "this string uses the wrong terminator'
-- A := "this string uses the wrong terminator' &
-- In these cases we give a different error message as well
-- We actually reposition the scan pointer to the point where we
-- place the flag in these cases, since it seems a better bet on
-- the original intention.
while Source (Scan_Ptr - 1) = ' '
or else Source (Scan_Ptr - 1) = '&'
loop
Scan_Ptr := Scan_Ptr - 1;
Unstore_String_Char;
end loop;
-- Check for case of incorrect string terminator, but single quote
-- is not considered incorrect if the opening terminator misused
-- a single quote (error message already given).
if Delimiter /= '''
and then Source (Scan_Ptr - 1) = '''
then
Unstore_String_Char;
Error_Msg
("incorrect string terminator character", Scan_Ptr - 1);
return;
end if;
-- Backup over semicolon or right-paren/semicolon sequence
if Source (Scan_Ptr - 1) = ';' then
Scan_Ptr := Scan_Ptr - 1;
Unstore_String_Char;
if Source (Scan_Ptr - 1) = ')' then
Scan_Ptr := Scan_Ptr - 1;
Unstore_String_Char;
end if;
end if;
-- See if there is a comma in the string, if so, guess that
-- the first comma terminates the string.
S := String_Start;
while S < Scan_Ptr loop
if Source (S) = ',' then
while Scan_Ptr > S loop
Scan_Ptr := Scan_Ptr - 1;
Unstore_String_Char;
end loop;
exit;
end if;
S := S + 1;
end loop;
-- Now we have adjusted the scan pointer, give message
Error_Msg_S -- CODEFIX
("missing string quote");
end Error_Unterminated_String;
----------------
-- Set_String --
----------------
procedure Set_String is
Slen : constant Int := Int (Scan_Ptr - Token_Ptr - 2);
C1 : Character;
C2 : Character;
C3 : Character;
begin
-- Token_Name is currently set to Error_Name. The following
-- section of code resets Token_Name to the proper Name_Op_xx
-- value if the string is a valid operator symbol, otherwise it is
-- left set to Error_Name.
if Slen = 1 then
C1 := Source (Token_Ptr + 1);
case C1 is
when '=' =>
Token_Name := Name_Op_Eq;
when '>' =>
Token_Name := Name_Op_Gt;
when '<' =>
Token_Name := Name_Op_Lt;
when '+' =>
Token_Name := Name_Op_Add;
when '-' =>
Token_Name := Name_Op_Subtract;
when '&' =>
Token_Name := Name_Op_Concat;
when '*' =>
Token_Name := Name_Op_Multiply;
when '/' =>
Token_Name := Name_Op_Divide;
when others =>
null;
end case;
elsif Slen = 2 then
C1 := Source (Token_Ptr + 1);
C2 := Source (Token_Ptr + 2);
if C1 = '*' and then C2 = '*' then
Token_Name := Name_Op_Expon;
elsif C2 = '=' then
if C1 = '/' then
Token_Name := Name_Op_Ne;
elsif C1 = '<' then
Token_Name := Name_Op_Le;
elsif C1 = '>' then
Token_Name := Name_Op_Ge;
end if;
elsif (C1 = 'O' or else C1 = 'o') and then -- OR
(C2 = 'R' or else C2 = 'r')
then
Token_Name := Name_Op_Or;
end if;
elsif Slen = 3 then
C1 := Source (Token_Ptr + 1);
C2 := Source (Token_Ptr + 2);
C3 := Source (Token_Ptr + 3);
if (C1 = 'A' or else C1 = 'a') and then -- AND
(C2 = 'N' or else C2 = 'n') and then
(C3 = 'D' or else C3 = 'd')
then
Token_Name := Name_Op_And;
elsif (C1 = 'A' or else C1 = 'a') and then -- ABS
(C2 = 'B' or else C2 = 'b') and then
(C3 = 'S' or else C3 = 's')
then
Token_Name := Name_Op_Abs;
elsif (C1 = 'M' or else C1 = 'm') and then -- MOD
(C2 = 'O' or else C2 = 'o') and then
(C3 = 'D' or else C3 = 'd')
then
Token_Name := Name_Op_Mod;
elsif (C1 = 'N' or else C1 = 'n') and then -- NOT
(C2 = 'O' or else C2 = 'o') and then
(C3 = 'T' or else C3 = 't')
then
Token_Name := Name_Op_Not;
elsif (C1 = 'R' or else C1 = 'r') and then -- REM
(C2 = 'E' or else C2 = 'e') and then
(C3 = 'M' or else C3 = 'm')
then
Token_Name := Name_Op_Rem;
elsif (C1 = 'X' or else C1 = 'x') and then -- XOR
(C2 = 'O' or else C2 = 'o') and then
(C3 = 'R' or else C3 = 'r')
then
Token_Name := Name_Op_Xor;
end if;
end if;
-- If it is an operator symbol, then Token_Name is set. If it is
-- some other string value, then Token_Name still contains
-- Error_Name.
if Token_Name = Error_Name then
Token := Tok_String_Literal;
else
Token := Tok_Operator_Symbol;
end if;
end Set_String;
-- Start of processing for Slit
begin
-- On entry, Scan_Ptr points to the opening character of the string
-- which is either a percent, double quote, or apostrophe (single
-- quote). The latter case is an error detected by the character
-- literal circuit.
String_Start := Scan_Ptr;
Delimiter := Source (Scan_Ptr);
Accumulate_Checksum (Delimiter);
Start_String;
Wide_Character_Found := False;
Wide_Wide_Character_Found := False;
Scan_Ptr := Scan_Ptr + 1;
-- Loop to scan out characters of string literal
loop
C := Source (Scan_Ptr);
if C = Delimiter then
Accumulate_Checksum (C);
Scan_Ptr := Scan_Ptr + 1;
exit when Source (Scan_Ptr) /= Delimiter;
Code := Get_Char_Code (C);
Accumulate_Checksum (C);
Scan_Ptr := Scan_Ptr + 1;
else
if C = '"' and then Delimiter = '%' then
Error_Msg_S
("quote not allowed in percent delimited string");
Code := Get_Char_Code (C);
Scan_Ptr := Scan_Ptr + 1;
elsif Start_Of_Wide_Character then
Wptr := Scan_Ptr;
Scan_Wide (Source, Scan_Ptr, Code, Err);
if Err then
Error_Illegal_Wide_Character;
Code := Get_Char_Code (' ');
else
Check_Bidi (Code);
end if;
Accumulate_Checksum (Code);
-- In Ada 95 mode we allow any wide characters in a string
-- but in Ada 2005, the set of characters allowed has been
-- restricted to graphic characters.
if Ada_Version >= Ada_2005
and then Is_UTF_32_Non_Graphic (UTF_32 (Code))
then
Error_Msg
("(Ada 2005) non-graphic character not permitted " &
"in string literal", Wptr);
end if;
else
Accumulate_Checksum (C);
if C not in Graphic_Character then
if C in Line_Terminator then
Error_Unterminated_String;
exit;
elsif C in Upper_Half_Character then
if Ada_Version = Ada_83 then
Error_Bad_String_Char;
end if;
else
Error_Bad_String_Char;
end if;
end if;
Code := Get_Char_Code (C);
Scan_Ptr := Scan_Ptr + 1;
end if;
end if;
Store_String_Char (Code);
if not In_Character_Range (Code) then
if In_Wide_Character_Range (Code) then
Wide_Character_Found := True;
else
Wide_Wide_Character_Found := True;
end if;
end if;
end loop;
String_Literal_Id := End_String;
Set_String;
return;
end Slit;
----------------------------------
-- Skip_Other_Format_Characters --
----------------------------------
procedure Skip_Other_Format_Characters is
P : Source_Ptr;
Code : Char_Code;
Err : Boolean;
begin
while Start_Of_Wide_Character loop
P := Scan_Ptr;
Scan_Wide (Source, Scan_Ptr, Code, Err);
if not Is_UTF_32_Other (UTF_32 (Code)) then
Scan_Ptr := P;
return;
end if;
end loop;
end Skip_Other_Format_Characters;
-----------------------------
-- Start_Of_Wide_Character --
-----------------------------
function Start_Of_Wide_Character return Boolean is
C : constant Character := Source (Scan_Ptr);
begin
-- ESC encoding method with ESC present
if C = ESC
and then Wide_Character_Encoding_Method in WC_ESC_Encoding_Method
then
return True;
-- Upper half character with upper half encoding
elsif C in Upper_Half_Character and then Upper_Half_Encoding then
return True;
-- Brackets encoding
elsif C = '['
and then Source (Scan_Ptr + 1) = '"'
and then Identifier_Char (Source (Scan_Ptr + 2))
then
return True;
-- Not the start of a wide character
else
return False;
end if;
end Start_Of_Wide_Character;
Token_Contains_Uppercase : Boolean;
-- Start of processing for Scan
begin
Prev_Token := Token;
Prev_Token_Ptr := Token_Ptr;
Token_Name := Error_Name;
-- The following loop runs more than once only if a format effector
-- (tab, vertical tab, form feed, line feed, carriage return) is
-- encountered and skipped, or some error situation, such as an
-- illegal character, is encountered.
<<Scan_Next_Character>>
loop
-- Skip past blanks, loop is opened up for speed
while Source (Scan_Ptr) = ' ' loop
if Source (Scan_Ptr + 1) /= ' ' then
Scan_Ptr := Scan_Ptr + 1;
exit;
end if;
if Source (Scan_Ptr + 2) /= ' ' then
Scan_Ptr := Scan_Ptr + 2;
exit;
end if;
if Source (Scan_Ptr + 3) /= ' ' then
Scan_Ptr := Scan_Ptr + 3;
exit;
end if;
if Source (Scan_Ptr + 4) /= ' ' then
Scan_Ptr := Scan_Ptr + 4;
exit;
end if;
if Source (Scan_Ptr + 5) /= ' ' then
Scan_Ptr := Scan_Ptr + 5;
exit;
end if;
if Source (Scan_Ptr + 6) /= ' ' then
Scan_Ptr := Scan_Ptr + 6;
exit;
end if;
if Source (Scan_Ptr + 7) /= ' ' then
Scan_Ptr := Scan_Ptr + 7;
exit;
end if;
Scan_Ptr := Scan_Ptr + 8;
end loop;
-- We are now at a non-blank character, which is the first character
-- of the token we will scan, and hence the value of Token_Ptr.
Token_Ptr := Scan_Ptr;
Token_Contains_Uppercase := False;
-- Here begins the main case statement which transfers control on the
-- basis of the non-blank character we have encountered.
case Source (Scan_Ptr) is
-- Line terminator characters
when CR | LF | FF | VT =>
goto Scan_Line_Terminator;
-- Horizontal tab, just skip past it
when HT =>
if Style_Check then
Style.Check_HT;
end if;
Scan_Ptr := Scan_Ptr + 1;
-- End of file character, treated as an end of file only if it is
-- the last character in the buffer, otherwise it is ignored.
when EOF =>
if Scan_Ptr = Source_Last (Current_Source_File) then
Check_End_Of_Line;
if Style_Check then
Style.Check_EOF;
end if;
Token := Tok_EOF;
return;
else
Scan_Ptr := Scan_Ptr + 1;
end if;
-- Ampersand
when '&' =>
Accumulate_Checksum ('&');
if Source (Scan_Ptr + 1) = '&' then
Error_Msg_S -- CODEFIX
("'&'& should be `AND THEN`");
Scan_Ptr := Scan_Ptr + 2;
Token := Tok_And;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Ampersand;
return;
end if;
-- AI12-0125-03 : @ is target_name
when '@' =>
Error_Msg_Ada_2022_Feature ("target name", Token_Ptr);
Accumulate_Checksum ('@');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_At_Sign;
return;
-- Asterisk (can be multiplication operator or double asterisk which
-- is the exponentiation compound delimiter).
when '*' =>
Accumulate_Checksum ('*');
if Source (Scan_Ptr + 1) = '*' then
Accumulate_Checksum ('*');
Scan_Ptr := Scan_Ptr + 2;
Token := Tok_Double_Asterisk;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Asterisk;
return;
end if;
-- Colon, which can either be an isolated colon, or part of an
-- assignment compound delimiter.
when ':' =>
Accumulate_Checksum (':');
if Double_Char_Token ('=') then
Token := Tok_Colon_Equal;
if Style_Check then
Style.Check_Colon_Equal;
end if;
return;
elsif Source (Scan_Ptr + 1) = '-'
and then Source (Scan_Ptr + 2) /= '-'
then
Token := Tok_Colon_Equal;
Error_Msg -- CODEFIX
(":- should be :=", Scan_Ptr);
Scan_Ptr := Scan_Ptr + 2;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Colon;
if Style_Check then
Style.Check_Colon;
end if;
return;
end if;
-- Left parenthesis
when '(' =>
Accumulate_Checksum ('(');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Left_Paren;
if Style_Check then
Style.Check_Left_Paren;
end if;
return;
-- Left bracket
when '[' =>
-- [] under -gnat2022 is an aggregate notation and the special
-- wide character notation becomes unsupported since the two
-- are ambiguous.
if Ada_Version >= Ada_2022 then
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Left_Bracket;
return;
elsif Source (Scan_Ptr + 1) = '"' then
goto Scan_Wide_Character;
else
Error_Msg_S ("illegal character, replaced by ""(""");
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Left_Paren;
return;
end if;
-- Left brace
when '{' =>
Error_Msg_S ("illegal character, replaced by ""(""");
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Left_Paren;
return;
-- Comma
when ',' =>
Accumulate_Checksum (',');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Comma;
if Style_Check then
Style.Check_Comma;
end if;
return;
-- Dot, which is either an isolated period, or part of a double dot
-- compound delimiter sequence. We also check for the case of a
-- digit following the period, to give a better error message.
when '.' =>
Accumulate_Checksum ('.');
if Double_Char_Token ('.') then
Token := Tok_Dot_Dot;
if Style_Check then
Style.Check_Dot_Dot;
end if;
return;
elsif Source (Scan_Ptr + 1) in '0' .. '9' then
Error_Msg_S ("numeric literal cannot start with point");
Scan_Ptr := Scan_Ptr + 1;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Dot;
return;
end if;
-- Equal, which can either be an equality operator, or part of the
-- arrow (=>) compound delimiter.
when '=' =>
Accumulate_Checksum ('=');
if Double_Char_Token ('>') then
Token := Tok_Arrow;
if Style_Check then
Style.Check_Arrow (Inside_Depends);
end if;
return;
elsif Source (Scan_Ptr + 1) = '=' then
Error_Msg_S -- CODEFIX
("== should be =");
Scan_Ptr := Scan_Ptr + 1;
end if;
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Equal;
return;
-- Greater than, which can be a greater than operator, greater than
-- or equal operator, or first character of a right label bracket.
when '>' =>
Accumulate_Checksum ('>');
if Double_Char_Token ('=') then
Token := Tok_Greater_Equal;
return;
elsif Double_Char_Token ('>') then
Token := Tok_Greater_Greater;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Greater;
return;
end if;
-- Less than, which can be a less than operator, less than or equal
-- operator, or the first character of a left label bracket, or the
-- first character of a box (<>) compound delimiter.
when '<' =>
Accumulate_Checksum ('<');
if Double_Char_Token ('=') then
Token := Tok_Less_Equal;
return;
elsif Double_Char_Token ('>') then
Token := Tok_Box;
if Style_Check then
Style.Check_Box;
end if;
return;
elsif Double_Char_Token ('<') then
Token := Tok_Less_Less;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Less;
return;
end if;
-- Minus, which is either a subtraction operator, or the first
-- character of double minus starting a comment
when '-' => Minus_Case : begin
if Source (Scan_Ptr + 1) = '>' then
Error_Msg_S ("invalid token");
Scan_Ptr := Scan_Ptr + 2;
Token := Tok_Arrow;
return;
elsif Source (Scan_Ptr + 1) /= '-' then
Accumulate_Checksum ('-');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Minus;
return;
-- Comment
else -- Source (Scan_Ptr + 1) = '-' then
if Style_Check then
Style.Check_Comment;
end if;
Scan_Ptr := Scan_Ptr + 2;
-- If we are in preprocessor mode with Replace_In_Comments set,
-- then we return the "--" as a token on its own.
if Replace_In_Comments then
Token := Tok_Comment;
return;
end if;
-- Otherwise scan out the comment
Start_Of_Comment := Scan_Ptr;
-- Loop to scan comment (this loop runs more than once only if
-- a horizontal tab or other non-graphic character is scanned)
loop
-- Scan to non graphic character (opened up for speed)
-- Note that we just eat left brackets, which means that
-- bracket notation cannot be used for end of line
-- characters in comments. This seems a reasonable choice,
-- since no one would ever use brackets notation in a real
-- program in this situation, and if we allow brackets
-- notation, we forbid some valid comments which contain a
-- brackets sequence that happens to match an end of line
-- character.
loop
exit when Source (Scan_Ptr) not in Graphic_Character;
Scan_Ptr := Scan_Ptr + 1;
exit when Source (Scan_Ptr) not in Graphic_Character;
Scan_Ptr := Scan_Ptr + 1;
exit when Source (Scan_Ptr) not in Graphic_Character;
Scan_Ptr := Scan_Ptr + 1;
exit when Source (Scan_Ptr) not in Graphic_Character;
Scan_Ptr := Scan_Ptr + 1;
exit when Source (Scan_Ptr) not in Graphic_Character;
Scan_Ptr := Scan_Ptr + 1;
end loop;
-- Keep going if horizontal tab
if Source (Scan_Ptr) = HT then
if Style_Check then
Style.Check_HT;
end if;
Scan_Ptr := Scan_Ptr + 1;
-- Terminate scan of comment if line terminator
elsif Source (Scan_Ptr) in Line_Terminator then
exit;
-- Terminate scan of comment if end of file encountered
-- (embedded EOF character or real last character in file)
elsif Source (Scan_Ptr) = EOF then
exit;
-- If we have a wide character, we have to scan it out,
-- because it might be a legitimate line terminator
elsif Start_Of_Wide_Character then
declare
Code : Char_Code;
Err : Boolean;
begin
Wptr := Scan_Ptr;
Scan_Wide (Source, Scan_Ptr, Code, Err);
-- If not well formed wide character, then just skip
-- past it and ignore it.
if Err then
Scan_Ptr := Wptr + 1;
-- If UTF_32 terminator, terminate comment scan
elsif Is_UTF_32_Line_Terminator (UTF_32 (Code)) then
Scan_Ptr := Wptr;
exit;
else
Check_Bidi (Code);
end if;
end;
-- Keep going if character in 80-FF range, or is ESC. These
-- characters are allowed in comments by RM-2.1(1), 2.7(2).
-- They are allowed even in Ada 83 mode according to the
-- approved AI. ESC was added to the AI in June 93.
elsif Source (Scan_Ptr) in Upper_Half_Character
or else Source (Scan_Ptr) = ESC
then
Scan_Ptr := Scan_Ptr + 1;
-- Otherwise we have an illegal comment character, ignore
-- this error in relaxed semantics mode.
else
if Relaxed_RM_Semantics then
Scan_Ptr := Scan_Ptr + 1;
else
Error_Illegal_Character;
end if;
end if;
end loop;
-- Note that, except when comments are tokens, we do NOT
-- execute a return here, instead we fall through to reexecute
-- the scan loop to look for a token.
if Comment_Is_Token then
Name_Len := Integer (Scan_Ptr - Start_Of_Comment);
Name_Buffer (1 .. Name_Len) :=
String (Source (Start_Of_Comment .. Scan_Ptr - 1));
Comment_Id := Name_Find;
Token := Tok_Comment;
return;
end if;
end if;
end Minus_Case;
-- Double quote or percent starting a string literal
when '"' | '%' =>
Slit;
Post_Scan;
return;
-- Apostrophe. This can either be the start of a character literal,
-- or an isolated apostrophe used in a qualified expression or an
-- attribute. In the following:
-- A := CHARACTER'('A');
-- the first apostrophe is treated as an isolated apostrophe, and the
-- second one is treated as the start of the character literal 'A'.
-- Note that RM-2.2(7) does not require a separator between "'" and
-- "(" in the above, so we cannot use lookahead to distinguish the
-- cases; we use look-back instead. Analysis of the grammar shows
-- that some tokens can be followed by an apostrophe, and some by a
-- character literal, but none by both. Some cannot be followed by
-- either, so it doesn't matter what we do in those cases, except to
-- get good error behavior.
when ''' => Char_Literal_Case : declare
Code : Char_Code;
Err : Boolean;
begin
Accumulate_Checksum (''');
Scan_Ptr := Scan_Ptr + 1;
-- Distinguish between apostrophe and character literal. It's an
-- apostrophe if the previous token is one of the following.
-- Reserved words are included for things like A.all'Address and
-- T'Digits'Img. Strings literals are included for things like
-- "abs"'Address. Other literals are included to give better error
-- behavior for illegal cases like 123'Img.
--
-- In Ada 2022, a target name (i.e. @) is a valid prefix of an
-- attribute, and functions like a name.
if Prev_Token = Tok_All
or else Prev_Token = Tok_At_Sign
or else Prev_Token = Tok_Delta
or else Prev_Token = Tok_Digits
or else Prev_Token = Tok_Identifier
or else Prev_Token = Tok_Project
or else Prev_Token = Tok_Right_Paren
or else Prev_Token = Tok_Right_Bracket
or else Prev_Token in Token_Class_Literal
then
Token := Tok_Apostrophe;
if Style_Check then
Style.Check_Apostrophe;
end if;
return;
-- Otherwise the apostrophe starts a character literal
else
-- Case of wide character literal
if Start_Of_Wide_Character then
Wptr := Scan_Ptr;
Scan_Wide (Source, Scan_Ptr, Code, Err);
if Err then
Error_Illegal_Wide_Character;
Code := Character'Pos (' ');
-- In Ada 95 mode we allow any wide character in a character
-- literal, but in later versions, the set of characters
-- allowed is restricted to graphic characters.
elsif Ada_Version >= Ada_2005
and then Is_UTF_32_Non_Graphic (UTF_32 (Code))
then
Error_Msg -- CODEFIX
("(Ada 2005) non-graphic character not permitted " &
"in character literal", Wptr);
else
Check_Bidi (Code);
end if;
Accumulate_Checksum (Code);
if Source (Scan_Ptr) /= ''' then
Error_Msg_S ("missing apostrophe");
else
Scan_Ptr := Scan_Ptr + 1;
end if;
-- If we do not find a closing quote in the expected place then
-- assume that we have a misguided attempt at a string literal.
-- However, if previous token is RANGE, then we return an
-- apostrophe instead since this gives better error recovery
elsif Source (Scan_Ptr + 1) /= ''' then
if Prev_Token = Tok_Range then
Token := Tok_Apostrophe;
return;
else
Scan_Ptr := Scan_Ptr - 1;
Error_Msg_S
("strings are delimited by double quote character");
Slit;
Post_Scan;
return;
end if;
-- Otherwise we have a (non-wide) character literal
else
Accumulate_Checksum (Source (Scan_Ptr));
if Source (Scan_Ptr) not in Graphic_Character then
if Source (Scan_Ptr) in Upper_Half_Character then
if Ada_Version = Ada_83 then
Error_Illegal_Character;
end if;
else
Error_Illegal_Character;
end if;
end if;
Code := Get_Char_Code (Source (Scan_Ptr));
Scan_Ptr := Scan_Ptr + 2;
end if;
-- Fall through here with Scan_Ptr updated past the closing
-- quote, and Code set to the Char_Code value for the literal
Accumulate_Checksum (''');
Token := Tok_Char_Literal;
Set_Character_Literal_Name (Code);
Token_Name := Name_Find;
Character_Code := Code;
Post_Scan;
return;
end if;
end Char_Literal_Case;
-- Right parenthesis
when ')' =>
Accumulate_Checksum (')');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Right_Paren;
if Style_Check then
Style.Check_Right_Paren;
end if;
return;
-- Right bracket or right brace, treated as right paren but proper
-- aggregate delimiter in Ada 2022.
when ']' | '}' =>
if Ada_Version >= Ada_2022 then
Token := Tok_Right_Bracket;
else
Error_Msg_S ("illegal character, replaced by "")""");
Token := Tok_Right_Paren;
end if;
Scan_Ptr := Scan_Ptr + 1;
return;
-- Slash (can be division operator or first character of not equal)
when '/' =>
Accumulate_Checksum ('/');
if Double_Char_Token ('=') then
Token := Tok_Not_Equal;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Slash;
return;
end if;
-- Semicolon
when ';' =>
Accumulate_Checksum (';');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Semicolon;
if Style_Check then
Style.Check_Semicolon;
end if;
return;
-- Vertical bar
when '|' => Vertical_Bar_Case : begin
Accumulate_Checksum ('|');
-- Special check for || to give nice message
if Source (Scan_Ptr + 1) = '|' then
Error_Msg_S -- CODEFIX
("""'|'|"" should be `OR ELSE`");
Scan_Ptr := Scan_Ptr + 2;
Token := Tok_Or;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Vertical_Bar;
if Style_Check then
Style.Check_Vertical_Bar;
end if;
Post_Scan;
return;
end if;
end Vertical_Bar_Case;
-- Exclamation, replacement character for vertical bar
when '!' => Exclamation_Case : begin
Accumulate_Checksum ('!');
if Source (Scan_Ptr + 1) = '=' then
Error_Msg_S -- CODEFIX
("'!= should be /=");
Scan_Ptr := Scan_Ptr + 2;
Token := Tok_Not_Equal;
return;
else
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Vertical_Bar;
Post_Scan;
return;
end if;
end Exclamation_Case;
-- Plus
when '+' => Plus_Case : begin
Accumulate_Checksum ('+');
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Plus;
return;
end Plus_Case;
-- Digits starting a numeric literal
when '0' .. '9' =>
-- First a bit of a scan ahead to see if we have a case of an
-- identifier starting with a digit (remembering exponent case).
declare
C : constant Character := Source (Scan_Ptr + 1);
begin
-- OK literal if digit followed by digit or underscore
if C in '0' .. '9' or else C = '_' then
null;
-- OK literal if digit not followed by identifier char
elsif not Identifier_Char (C) then
null;
-- OK literal if digit followed by e/E followed by digit/sign.
-- We also allow underscore after the E, which is an error, but
-- better handled by Nlit than deciding this is an identifier.
elsif (C = 'e' or else C = 'E')
and then (Source (Scan_Ptr + 2) in '0' .. '9'
or else Source (Scan_Ptr + 2) = '+'
or else Source (Scan_Ptr + 2) = '-'
or else Source (Scan_Ptr + 2) = '_')
then
null;
-- Here we have what really looks like an identifier that
-- starts with a digit, so give error msg.
else
Error_Msg_S ("identifier may not start with digit");
Name_Len := 1;
Underline_Found := False;
Name_Buffer (1) := Source (Scan_Ptr);
Accumulate_Checksum (Name_Buffer (1));
Scan_Ptr := Scan_Ptr + 1;
goto Scan_Identifier;
end if;
end;
-- Here we have an OK integer literal
Nlit;
-- Check for proper delimiter, ignoring other format characters
Skip_Other_Format_Characters;
if Identifier_Char (Source (Scan_Ptr)) then
Error_Msg_S
("delimiter required between literal and identifier");
end if;
Post_Scan;
return;
-- Lower case letters
when 'a' .. 'z' =>
Name_Len := 1;
Underline_Found := False;
Name_Buffer (1) := Source (Scan_Ptr);
Accumulate_Checksum (Name_Buffer (1));
Scan_Ptr := Scan_Ptr + 1;
goto Scan_Identifier;
-- Upper case letters
when 'A' .. 'Z' =>
Token_Contains_Uppercase := True;
Name_Len := 1;
Underline_Found := False;
Name_Buffer (1) :=
Character'Val (Character'Pos (Source (Scan_Ptr)) + 32);
Accumulate_Checksum (Name_Buffer (1));
Scan_Ptr := Scan_Ptr + 1;
goto Scan_Identifier;
-- Underline character
when '_' =>
if Special_Characters ('_') then
Token_Ptr := Scan_Ptr;
Scan_Ptr := Scan_Ptr + 1;
Token := Tok_Special;
Special_Character := '_';
return;
end if;
Error_Msg_S ("identifier cannot start with underline");
Name_Len := 1;
Name_Buffer (1) := '_';
Scan_Ptr := Scan_Ptr + 1;
Underline_Found := False;
goto Scan_Identifier;
-- Space (not possible, because we scanned past blanks)
when ' ' =>
raise Program_Error;
-- Characters in top half of ASCII 8-bit chart
when Upper_Half_Character =>
-- Wide character case
if Upper_Half_Encoding then
goto Scan_Wide_Character;
-- Otherwise we have OK Latin-1 character
else
-- Upper half characters may possibly be identifier letters
-- but can never be digits, so Identifier_Char can be used to
-- test for a valid start of identifier character.
if Identifier_Char (Source (Scan_Ptr)) then
Name_Len := 0;
Underline_Found := False;
goto Scan_Identifier;
else
Error_Illegal_Character;
end if;
end if;
when ESC =>
-- ESC character, possible start of identifier if wide characters
-- using ESC encoding are allowed in identifiers, which we can
-- tell by looking at the Identifier_Char flag for ESC, which is
-- only true if these conditions are met. In Ada 2005 mode, may
-- also be valid UTF_32 space or line terminator character.
if Identifier_Char (ESC) then
Name_Len := 0;
goto Scan_Wide_Character;
else
Error_Illegal_Character;
end if;
-- Invalid control characters
when ACK
| ASCII.SO
| BEL
| BS
| CAN
| DC1
| DC2
| DC3
| DC4
| DEL
| DLE
| EM
| ENQ
| EOT
| ETB
| ETX
| FS
| GS
| NAK
| NUL
| RS
| SI
| SOH
| STX
| SYN
| US
=>
Error_Illegal_Character;
-- Invalid graphic characters
-- Note that '@' is handled elsewhere, because following AI12-125
-- it denotes the target_name of an assignment.
when '#' | '$' | '?' | '`' | '\' | '^' | '~' =>
-- If Set_Special_Character has been called for this character,
-- set Scans.Special_Character and return a Special token.
if Special_Characters (Source (Scan_Ptr)) then
Token_Ptr := Scan_Ptr;
Token := Tok_Special;
Special_Character := Source (Scan_Ptr);
Scan_Ptr := Scan_Ptr + 1;
return;
-- Check for something looking like a preprocessor directive
elsif Source (Scan_Ptr) = '#'
and then (Source (Scan_Ptr + 1 .. Scan_Ptr + 2) = "if"
or else
Source (Scan_Ptr + 1 .. Scan_Ptr + 5) = "elsif"
or else
Source (Scan_Ptr + 1 .. Scan_Ptr + 4) = "else"
or else
Source (Scan_Ptr + 1 .. Scan_Ptr + 3) = "end")
then
Error_Msg_S
("preprocessor directive ignored, preprocessor not active");
-- Skip to end of line
loop
if Source (Scan_Ptr) in Graphic_Character
or else
Source (Scan_Ptr) = HT
then
Scan_Ptr := Scan_Ptr + 1;
-- Done if line terminator or EOF
elsif Source (Scan_Ptr) in Line_Terminator
or else
Source (Scan_Ptr) = EOF
then
exit;
-- If we have a wide character, we have to scan it out,
-- because it might be a legitimate line terminator
elsif Start_Of_Wide_Character then
declare
Wptr : constant Source_Ptr := Scan_Ptr;
Code : Char_Code;
Err : Boolean;
begin
Scan_Wide (Source, Scan_Ptr, Code, Err);
-- If not well formed wide character, then just skip
-- past it and ignore it.
if Err then
Scan_Ptr := Wptr + 1;
-- If UTF_32 terminator, terminate comment scan
elsif Is_UTF_32_Line_Terminator (UTF_32 (Code)) then
Scan_Ptr := Wptr;
exit;
end if;
end;
-- Else keep going (don't worry about bad comment chars
-- in this context, we just want to find the end of line.
else
Scan_Ptr := Scan_Ptr + 1;
end if;
end loop;
-- Otherwise, this is an illegal character
else
Error_Illegal_Character;
end if;
-- End switch on non-blank character
end case;
-- End loop past format effectors. The exit from this loop is by
-- executing a return statement following completion of token scan
-- (control never falls out of this loop to the code that follows).
end loop;
pragma Assert (False);
-- Wide_Character scanning routine. On entry we have encountered the
-- initial character of a wide character sequence.
<<Scan_Wide_Character>>
declare
Code : Char_Code;
Cat : Category;
Err : Boolean;
begin
Wptr := Scan_Ptr;
Scan_Wide (Source, Scan_Ptr, Code, Err);
-- If bad wide character, signal error and continue scan
if Err then
Error_Illegal_Wide_Character;
goto Scan_Next_Character;
end if;
Cat := Get_Category (UTF_32 (Code));
-- If OK letter, reset scan ptr and go scan identifier
if Is_UTF_32_Letter (Cat) then
Scan_Ptr := Wptr;
Name_Len := 0;
Underline_Found := False;
goto Scan_Identifier;
-- If OK wide space, ignore and keep scanning (we do not include
-- any ignored spaces in checksum)
elsif Is_UTF_32_Space (Cat) then
goto Scan_Next_Character;
-- If other format character, ignore and keep scanning (again we
-- do not include in the checksum) (this is for AI-0079).
elsif Is_UTF_32_Other (Cat) then
goto Scan_Next_Character;
-- If OK wide line terminator, terminate current line
elsif Is_UTF_32_Line_Terminator (UTF_32 (Code)) then
Scan_Ptr := Wptr;
goto Scan_Line_Terminator;
-- Punctuation is an error (at start of identifier)
elsif Is_UTF_32_Punctuation (Cat) then
Error_Msg ("identifier cannot start with punctuation", Wptr);
Scan_Ptr := Wptr;
Name_Len := 0;
Underline_Found := False;
goto Scan_Identifier;
-- Mark character is an error (at start of identifier)
elsif Is_UTF_32_Mark (Cat) then
Error_Msg ("identifier cannot start with mark character", Wptr);
Scan_Ptr := Wptr;
Name_Len := 0;
Underline_Found := False;
goto Scan_Identifier;
-- Extended digit character is an error. Could be bad start of
-- identifier or bad literal. Not worth doing too much to try to
-- distinguish these cases, but we will do a little bit.
elsif Is_UTF_32_Digit (Cat) then
Error_Msg
("identifier cannot start with digit character", Wptr);
Scan_Ptr := Wptr;
Name_Len := 0;
Underline_Found := False;
goto Scan_Identifier;
-- All other wide characters are illegal here
else
Error_Illegal_Wide_Character;
goto Scan_Next_Character;
end if;
end;
-- Routine to scan line terminator. On entry Scan_Ptr points to a
-- character which is one of FF,LR,CR,VT, or one of the wide characters
-- that is treated as a line terminator.
<<Scan_Line_Terminator>>
-- Check line too long
Check_End_Of_Line;
-- Set Token_Ptr, if End_Of_Line is a token, for the case when it is
-- a physical line.
if End_Of_Line_Is_Token then
Token_Ptr := Scan_Ptr;
end if;
declare
Physical : Boolean;
begin
Skip_Line_Terminators (Scan_Ptr, Physical);
-- If we are at start of physical line, update scan pointers to
-- reflect the start of the new line.
if Physical then
Current_Line_Start := Scan_Ptr;
Start_Column := Set_Start_Column;
First_Non_Blank_Location := Scan_Ptr;
-- If End_Of_Line is a token, we return it as it is a
-- physical line.
if End_Of_Line_Is_Token then
Token := Tok_End_Of_Line;
return;
end if;
end if;
end;
goto Scan_Next_Character;
-- Identifier scanning routine. On entry, some initial characters of
-- the identifier may have already been stored in Name_Buffer. If so,
-- Name_Len has the number of characters stored, otherwise Name_Len is
-- set to zero on entry. Underline_Found is also set False on entry.
<<Scan_Identifier>>
-- This loop scans as fast as possible past lower half letters and
-- digits, which we expect to be the most common characters.
loop
if Source (Scan_Ptr) in 'a' .. 'z'
or else Source (Scan_Ptr) in '0' .. '9'
then
Name_Buffer (Name_Len + 1) := Source (Scan_Ptr);
Accumulate_Checksum (Source (Scan_Ptr));
elsif Source (Scan_Ptr) in 'A' .. 'Z' then
Token_Contains_Uppercase := True;
Name_Buffer (Name_Len + 1) :=
Character'Val (Character'Pos (Source (Scan_Ptr)) + 32);
Accumulate_Checksum (Name_Buffer (Name_Len + 1));
else
exit;
end if;
Underline_Found := False;
Scan_Ptr := Scan_Ptr + 1;
Name_Len := Name_Len + 1;
end loop;
-- If we fall through, then we have encountered either an underline
-- character, or an extended identifier character (i.e. one from the
-- upper half), or a wide character, or an identifier terminator. The
-- initial test speeds us up in the most common case where we have
-- an identifier terminator. Note that ESC is an identifier character
-- only if a wide character encoding method that uses ESC encoding
-- is active, so if we find an ESC character we know that we have a
-- wide character.
if Identifier_Char (Source (Scan_Ptr))
or else (Source (Scan_Ptr) in Upper_Half_Character
and then Upper_Half_Encoding)
then
-- Case of underline
if Source (Scan_Ptr) = '_' then
Accumulate_Checksum ('_');
if Underline_Found then
Error_No_Double_Underline;
else
Underline_Found := True;
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := '_';
end if;
Scan_Ptr := Scan_Ptr + 1;
goto Scan_Identifier;
-- Upper half character
elsif Source (Scan_Ptr) in Upper_Half_Character
and then not Upper_Half_Encoding
then
Accumulate_Checksum (Source (Scan_Ptr));
Store_Encoded_Character
(Get_Char_Code (Fold_Lower (Source (Scan_Ptr))));
Scan_Ptr := Scan_Ptr + 1;
Underline_Found := False;
goto Scan_Identifier;
-- Left bracket not followed by a quote terminates an identifier.
-- This is an error, but we don't want to give a junk error msg
-- about wide characters in this case.
elsif Source (Scan_Ptr) = '['
and then Source (Scan_Ptr + 1) /= '"'
then
null;
-- We know we have a wide character encoding here (the current
-- character is either ESC, left bracket, or an upper half
-- character depending on the encoding method).
else
-- Scan out the wide character and insert the appropriate
-- encoding into the name table entry for the identifier.
declare
Code : Char_Code;
Err : Boolean;
Chr : Character;
Cat : Category;
begin
Wptr := Scan_Ptr;
Scan_Wide (Source, Scan_Ptr, Code, Err);
-- If error, signal error
if Err then
Error_Illegal_Wide_Character;
-- If the character scanned is a normal identifier
-- character, then we treat it that way.
elsif In_Character_Range (Code)
and then Identifier_Char (Get_Character (Code))
then
Chr := Get_Character (Code);
Accumulate_Checksum (Chr);
Store_Encoded_Character
(Get_Char_Code (Fold_Lower (Chr)));
Underline_Found := False;
-- Here if not a normal identifier character
else
Cat := Get_Category (UTF_32 (Code));
-- Wide character in Unicode category "Other, Format"
-- is not accepted in an identifier. This is because it
-- it is considered a security risk (AI-0091).
-- However, it is OK for such a character to appear at
-- the end of an identifier.
if Is_UTF_32_Other (Cat) then
if not Identifier_Char (Source (Scan_Ptr)) then
goto Scan_Identifier_Complete;
else
Error_Msg
("identifier cannot contain other_format "
& "character", Wptr);
goto Scan_Identifier;
end if;
-- Wide character in category Separator,Space terminates
elsif Is_UTF_32_Space (Cat) then
goto Scan_Identifier_Complete;
end if;
-- Here if wide character is part of the identifier
-- Make sure we are allowing wide characters in
-- identifiers. Note that we allow wide character
-- notation for an OK identifier character. This in
-- particular allows bracket or other notation to be
-- used for upper half letters.
-- Wide characters are always allowed in Ada 2005
if Identifier_Character_Set /= 'w'
and then Ada_Version < Ada_2005
then
Error_Msg
("wide character not allowed in identifier", Wptr);
end if;
-- AI12-0004: An identifier shall only contain characters
-- that may be present in Normalization Form KC.
if not Is_UTF_32_NFKC (UTF_32 (Code)) then
Error_Msg
("invalid wide character in identifier", Wptr);
-- If OK letter, store it folding to upper case. Note
-- that we include the folded letter in the checksum.
elsif Is_UTF_32_Letter (Cat) then
Code :=
Char_Code (UTF_32_To_Upper_Case (UTF_32 (Code)));
Accumulate_Checksum (Code);
Store_Encoded_Character (Code);
Underline_Found := False;
-- If OK extended digit or mark, then store it
elsif Is_UTF_32_Digit (Cat)
or else Is_UTF_32_Mark (Cat)
then
Accumulate_Checksum (Code);
Store_Encoded_Character (Code);
Underline_Found := False;
-- Wide punctuation is also stored, but counts as an
-- underline character for error checking purposes.
elsif Is_UTF_32_Punctuation (Cat) then
Accumulate_Checksum (Code);
if Underline_Found then
declare
Cend : constant Source_Ptr := Scan_Ptr;
begin
Scan_Ptr := Wptr;
Error_No_Double_Underline;
Scan_Ptr := Cend;
end;
else
Store_Encoded_Character (Code);
Underline_Found := True;
end if;
-- Any other wide character is not acceptable
else
Error_Msg
("invalid wide character in identifier", Wptr);
end if;
end if;
goto Scan_Identifier;
end;
end if;
end if;
-- Scan of identifier is complete. The identifier is stored in
-- Name_Buffer, and Scan_Ptr points past the last character.
<<Scan_Identifier_Complete>>
Token_Name := Name_Find;
-- Check for identifier ending with underline or punctuation char
if Underline_Found then
Underline_Found := False;
if Source (Scan_Ptr - 1) = '_' then
Error_Msg
("identifier cannot end with underline", Scan_Ptr - 1);
else
Error_Msg
("identifier cannot end with punctuation character", Wptr);
end if;
end if;
-- We will assume it is an identifier, not a keyword, so that the
-- checksum is independent of the Ada version.
Token := Tok_Identifier;
-- Check if it is a keyword
if Is_Keyword_Name (Token_Name) then
Accumulate_Token_Checksum;
Token := Token_Type'Val (Get_Name_Table_Byte (Token_Name));
-- See Exp_Put_Image for documentation of Tagged_Seen
if Token = Tok_Tagged then
Tagged_Seen := True;
end if;
-- Keyword style checks
if Style_Check then
-- Deal with possible style check for non-lower case keyword,
-- but we don't treat ACCESS, DELTA, DIGITS, RANGE as keywords
-- for this purpose if they appear as attribute designators.
-- Actually we only check the first character for speed.
-- Ada 2005 (AI-284): Do not apply the style check in case of
-- "pragma Interface"
-- Ada 2005 (AI-340): Do not apply the style check in case of
-- MOD attribute.
if Token_Contains_Uppercase
and then (Prev_Token /= Tok_Apostrophe
or else
(Token /= Tok_Access and then
Token /= Tok_Delta and then
Token /= Tok_Digits and then
Token /= Tok_Mod and then
Token /= Tok_Range))
and then (Token /= Tok_Interface
or else
(Token = Tok_Interface
and then Prev_Token /= Tok_Pragma))
then
Style.Non_Lower_Case_Keyword;
end if;
-- Check THEN/ELSE style rules. These do not apply to AND THEN
-- or OR ELSE, and do not apply in if expressions.
if (Token = Tok_Then and then Prev_Token /= Tok_And)
or else
(Token = Tok_Else and then Prev_Token /= Tok_Or)
then
if Inside_If_Expression = 0 then
Style.Check_Separate_Stmt_Lines;
end if;
end if;
end if;
-- We must reset Token_Name since this is not an identifier and
-- if we leave Token_Name set, the parser gets confused because
-- it thinks it is dealing with an identifier instead of the
-- corresponding keyword.
Token_Name := No_Name;
return;
-- It is an identifier after all
else
Accumulate_Token_Checksum;
Post_Scan;
end if;
end Scan;
--------------------------
-- Set_Comment_As_Token --
--------------------------
procedure Set_Comment_As_Token (Value : Boolean) is
begin
Comment_Is_Token := Value;
end Set_Comment_As_Token;
------------------------------
-- Set_End_Of_Line_As_Token --
------------------------------
procedure Set_End_Of_Line_As_Token (Value : Boolean) is
begin
End_Of_Line_Is_Token := Value;
end Set_End_Of_Line_As_Token;
---------------------------
-- Set_Special_Character --
---------------------------
procedure Set_Special_Character (C : Character) is
begin
case C is
when '#' | '$' | '_' | '?' | '@' | '`' | '\' | '^' | '~' =>
Special_Characters (C) := True;
when others =>
null;
end case;
end Set_Special_Character;
----------------------
-- Set_Start_Column --
----------------------
-- Note: it seems at first glance a little expensive to compute this value
-- for every source line (since it is certainly not used for all source
-- lines). On the other hand, it doesn't take much more work to skip past
-- the initial white space on the line counting the columns than it would
-- to scan past the white space using the standard scanning circuits.
function Set_Start_Column return Column_Number is
Start_Column : Column_Number := 0;
begin
-- Outer loop scans past horizontal tab characters
Tabs_Loop : loop
-- Inner loop scans past blanks, bumping Scan_Ptr past the blanks and
-- adjusting Start_Column to account for them.
Blanks_Loop :
while Source (Scan_Ptr) = ' ' loop
Scan_Ptr := Scan_Ptr + 1;
Start_Column := Start_Column + 1;
end loop Blanks_Loop;
-- Outer loop keeps going only if a horizontal tab follows
if Source (Scan_Ptr) = HT then
if Style_Check then
Style.Check_HT;
end if;
Scan_Ptr := Scan_Ptr + 1;
Start_Column := (Start_Column / 8) * 8 + 8;
else
exit Tabs_Loop;
end if;
end loop Tabs_Loop;
return Start_Column;
-- A constraint error can happen only if we have a compiler with checks on
-- and a line with a ludicrous number of tabs or spaces at the start. In
-- such a case, we really don't care if Start_Column is right or not.
exception
when Constraint_Error =>
return Column_Number'Last;
end Set_Start_Column;
end Scng;