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-- --
-- --
-- P A R . C H 2 --
-- --
-- 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 --
-- 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. --
-- --
pragma Style_Checks (All_Checks);
-- Turn off subprogram body ordering check. Subprograms are in order
-- by RM section rather than alphabetical
separate (Par)
package body Ch2 is
-- Local functions, used only in this chapter
procedure Scan_Pragma_Argument_Association
(Identifier_Seen : in out Boolean;
Association : out Node_Id;
Reserved_Words_OK : Boolean := False);
-- Scans out a pragma argument association. Identifier_Seen is True on
-- entry if a previous association had an identifier, and gets set True
-- if the scanned association has an identifier (this is used to check the
-- rule that no associations without identifiers can follow an association
-- which has an identifier). The result is returned in Association. Flag
-- For_Pragma_Restrictions should be set when arguments are being parsed
-- for pragma Restrictions.
-- Note: We allow attribute forms Pre'Class, Post'Class, Invariant'Class,
-- Type_Invariant'Class in place of a pragma argument identifier. Rather
-- than handle this case specially, we replace such references with
-- one of the special internal identifiers _Pre, _Post, _Invariant, or
-- _Type_Invariant, and this procedure is where this replacement occurs.
-- 2.3 Identifier --
-- An IDENTIFIER shall not be a reserved word
-- Error recovery: can raise Error_Resync (cannot return Error)
function P_Identifier
(C : Id_Check := None;
Force_Msg : Boolean := False)
return Node_Id
Ident_Node : Node_Id;
-- All set if we do indeed have an identifier
if Token = Tok_Identifier then
-- If we have a reserved identifier, manufacture an identifier with
-- a corresponding name after posting an appropriate error message
elsif Is_Reserved_Identifier (C) then
Scan_Reserved_Identifier (Force_Msg => Force_Msg);
-- Otherwise we have junk that cannot be interpreted as an identifier
T_Identifier; -- to give message
raise Error_Resync;
end if;
if Style_Check then
end if;
Ident_Node := Token_Node;
Scan; -- past the identifier
return Ident_Node;
end P_Identifier;
-- 2.3 Letter Or Digit --
-- Parsed by P_Identifier (2.3)
-- 2.4 Numeric Literal --
-- Numeric literal is returned by the scanner as either
-- Tok_Integer_Literal or Tok_Real_Literal
-- 2.4.1 Decimal Literal --
-- Handled by scanner as part of numeric literal handing (see 2.4)
-- 2.4.1 Numeral --
-- Handled by scanner as part of numeric literal handling (see 2.4)
-- 2.4.1 Exponent --
-- Handled by scanner as part of numeric literal handling (see 2.4)
-- 2.4.2 Based Literal --
-- Handled by scanner as part of numeric literal handling (see 2.4)
-- 2.4.2 Base --
-- Handled by scanner as part of numeric literal handling (see 2.4)
-- 2.4.2 Based Numeral --
-- Handled by scanner as part of numeric literal handling (see 2.4)
-- 2.4.2 Extended Digit --
-- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F
-- Handled by scanner as part of numeric literal handling (see 2.4)
-- 2.5 Character Literal --
-- Handled by the scanner and returned as Tok_Char_Literal
-- 2.6 String Literal --
-- Handled by the scanner and returned as Tok_String_Literal
-- or if the string looks like an operator as Tok_Operator_Symbol.
-- 2.6 String Element --
-- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER
-- A STRING_ELEMENT is either a pair of quotation marks ("),
-- or a single GRAPHIC_CHARACTER other than a quotation mark.
-- Handled by scanner as part of string literal handling (see 2.4)
-- 2.7 Comment --
-- A COMMENT starts with two adjacent hyphens and extends up to the
-- end of the line. A COMMENT may appear on any line of a program.
-- Handled by the scanner which simply skips past encountered comments
-- 2.8 Pragma --
-- The caller has checked that the initial token is PRAGMA
-- Error recovery: cannot raise Error_Resync
-- One special piece of processing is needed in this routine. As described
-- in the section on "Handling semicolon used in place of IS" in module
-- Parse, the parser detects the case of missing subprogram bodies to
-- allow recovery from this syntactic error. Pragma INTERFACE (and, for
-- Ada 95, pragma IMPORT) can appear in place of the body. The parser must
-- recognize the use of these two pragmas in this context, otherwise it
-- will think there are missing bodies, and try to change ; to IS, when
-- in fact the bodies ARE present, supplied by these pragmas.
function P_Pragma (Skipping : Boolean := False) return Node_Id is
procedure Skip_Pragma_Semicolon;
-- Skip past semicolon at end of pragma
-- Skip_Pragma_Semicolon --
procedure Skip_Pragma_Semicolon is
-- If skipping the pragma, ignore a missing semicolon
if Token /= Tok_Semicolon and then Skipping then
-- Otherwise demand a semicolon
end if;
end Skip_Pragma_Semicolon;
-- Local variables
Import_Check_Required : Boolean := False;
-- Set True if check of pragma IMPORT or INTERFACE is required
Arg_Count : Nat := 0;
-- Number of argument associations processed
Identifier_Seen : Boolean := False;
-- Set True if an identifier is encountered for a pragma argument. Used
-- to check that there are no more arguments without identifiers.
Assoc_Node : Node_Id;
Ident_Node : Node_Id;
Prag_Name : Name_Id;
Prag_Node : Node_Id;
Result : Node_Id;
Semicolon_Loc : Source_Ptr;
-- Start of processing for P_Pragma
Inside_Pragma := True;
Prag_Node := New_Node (N_Pragma, Token_Ptr);
Scan; -- past PRAGMA
Prag_Name := Token_Name;
if Style_Check then
end if;
-- Ada 2005 (AI-284): INTERFACE is a new reserved word but it is
-- allowed as a pragma name.
if Is_Reserved_Keyword (Token) then
Prag_Name := Keyword_Name (Token);
Ident_Node := Make_Identifier (Token_Ptr, Prag_Name);
Scan; -- past the keyword
Ident_Node := P_Identifier;
end if;
Set_Pragma_Identifier (Prag_Node, Ident_Node);
-- See if special INTERFACE/IMPORT check is required
if SIS_Entry_Active then
Import_Check_Required :=
(Prag_Name = Name_Import) or else (Prag_Name = Name_Interface);
Import_Check_Required := False;
end if;
-- Set global to indicate if we are within a Depends pragma
if Chars (Ident_Node) = Name_Depends
or else Chars (Ident_Node) = Name_Refined_Depends
Inside_Depends := True;
end if;
-- Scan arguments. We assume that arguments are present if there is
-- a left paren, or if a semicolon is missing and there is another
-- token on the same line as the pragma name.
if Token = Tok_Left_Paren
or else (Token /= Tok_Semicolon
and then not Token_Is_At_Start_Of_Line)
Set_Pragma_Argument_Associations (Prag_Node, New_List);
Arg_Count := Arg_Count + 1;
(Identifier_Seen => Identifier_Seen,
Association => Assoc_Node,
Reserved_Words_OK =>
Prag_Name in Name_Restriction_Warnings | Name_Restrictions);
if Arg_Count = 2 and then Import_Check_Required then
-- Here is where we cancel the SIS active status if this pragma
-- supplies a body for the currently active subprogram spec.
if Nkind (Expression (Assoc_Node)) in N_Direct_Name
and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl)
SIS_Entry_Active := False;
end if;
end if;
Append (Assoc_Node, Pragma_Argument_Associations (Prag_Node));
exit when Token /= Tok_Comma;
Scan; -- past comma
end loop;
-- If we have := for pragma Debug, it is worth special casing the
-- error message (it is easy to think of pragma Debug as taking a
-- statement, and an assignment statement is the most likely
-- candidate for this error)
if Token = Tok_Colon_Equal and then Prag_Name = Name_Debug then
Error_Msg_SC ("argument for pragma Debug must be procedure call");
-- Normal case, we expect a right paren here
end if;
end if;
Semicolon_Loc := Token_Ptr;
-- Cancel indication of being within a pragma or in particular a Depends
-- pragma.
Inside_Depends := False;
Inside_Pragma := False;
-- Now we have two tasks left, we need to scan out the semicolon
-- following the pragma, and we have to call Par.Prag to process
-- the pragma. Normally we do them in this order, however, there
-- is one exception namely pragma Style_Checks where we like to
-- skip the semicolon after processing the pragma, since that way
-- the style checks for the scanning of the semicolon follow the
-- settings of the pragma.
-- You might think we could just unconditionally do things in
-- the opposite order, but there are other pragmas, notably the
-- case of pragma Source_File_Name, which assume the semicolon
-- is already scanned out.
if Prag_Name = Name_Style_Checks then
Result := Par.Prag (Prag_Node, Semicolon_Loc);
return Result;
return Par.Prag (Prag_Node, Semicolon_Loc);
end if;
when Error_Resync =>
Inside_Depends := False;
Inside_Pragma := False;
return Error;
end P_Pragma;
-- This routine is called if a pragma is encountered in an inappropriate
-- position, the pragma is scanned out and control returns to continue.
-- The caller has checked that the initial token is pragma
-- Error recovery: cannot raise Error_Resync
procedure P_Pragmas_Misplaced is
while Token = Tok_Pragma loop
Error_Msg_SC ("pragma not allowed here");
Discard_Junk_Node (P_Pragma (Skipping => True));
end loop;
end P_Pragmas_Misplaced;
-- This function is called to scan out an optional sequence of pragmas.
-- If no pragmas are found, then No_List is returned.
-- Error recovery: Cannot raise Error_Resync
function P_Pragmas_Opt return List_Id is
L : List_Id;
if Token = Tok_Pragma then
L := New_List;
P_Pragmas_Opt (L);
return L;
return No_List;
end if;
end P_Pragmas_Opt;
-- This procedure is called to scan out an optional sequence of pragmas.
-- Any pragmas found are appended to the list provided as an argument.
-- Error recovery: Cannot raise Error_Resync
procedure P_Pragmas_Opt (List : List_Id) is
P : Node_Id;
while Token = Tok_Pragma loop
P := P_Pragma;
if Nkind (P) /= N_Error
and then Pragma_Name_Unmapped (P) in Name_Assert | Name_Debug
Error_Msg_Name_1 := Pragma_Name_Unmapped (P);
("pragma% must be in declaration/statement context", P);
Append (P, List);
end if;
end loop;
end P_Pragmas_Opt;
-- 2.8 Pragma_Argument Association --
-- [pragma_argument_IDENTIFIER =>] NAME
-- | [pragma_argument_IDENTIFIER =>] EXPRESSION
-- In Ada 2012, there are two more possibilities:
-- [pragma_argument_ASPECT_MARK =>] NAME
-- | [pragma_argument_ASPECT_MARK =>] EXPRESSION
-- where the interesting allowed cases (which do not fit the syntax of the
-- first alternative above) are
-- Pre'Class | Post'Class | Invariant'Class | Type_Invariant'Class
-- We allow this special usage in all Ada modes, but it would be a pain to
-- allow these aspects to pervade the pragma syntax, and the representation
-- of pragma nodes internally. So what we do is to replace these
-- ASPECT_MARK forms with identifiers whose name is one of the special
-- internal names _Pre, _Post, _Invariant, or _Type_Invariant.
-- Error recovery: cannot raise Error_Resync
procedure Scan_Pragma_Argument_Association
(Identifier_Seen : in out Boolean;
Association : out Node_Id;
Reserved_Words_OK : Boolean := False)
function P_Expression_Or_Reserved_Word return Node_Id;
-- Parse an expression or, if the token is one of the following reserved
-- words, construct an identifier with proper Chars field.
-- Access
-- Delta
-- Digits
-- Mod
-- Range
-- P_Expression_Or_Reserved_Word --
function P_Expression_Or_Reserved_Word return Node_Id is
Word : Node_Id;
Word_Id : Name_Id;
Word_Id := No_Name;
if Token = Tok_Access then
Word_Id := Name_Access;
Scan; -- past ACCESS
elsif Token = Tok_Delta then
Word_Id := Name_Delta;
Scan; -- past DELTA
elsif Token = Tok_Digits then
Word_Id := Name_Digits;
Scan; -- past DIGITS
elsif Token = Tok_Mod then
Word_Id := Name_Mod;
Scan; -- past MOD
elsif Token = Tok_Range then
Word_Id := Name_Range;
Scan; -- post RANGE
end if;
if Word_Id = No_Name then
return P_Expression;
Word := New_Node (N_Identifier, Token_Ptr);
Set_Chars (Word, Word_Id);
return Word;
end if;
end P_Expression_Or_Reserved_Word;
-- Local variables
Expression_Node : Node_Id;
Identifier_Node : Node_Id;
Identifier_OK : Boolean;
Scan_State : Saved_Scan_State;
-- Start of processing for Scan_Pragma_Argument_Association
Association := New_Node (N_Pragma_Argument_Association, Token_Ptr);
Set_Chars (Association, No_Name);
Identifier_OK := False;
-- Argument starts with identifier
if Token = Tok_Identifier then
Identifier_Node := Token_Node;
Save_Scan_State (Scan_State); -- at Identifier
Scan; -- past Identifier
if Token = Tok_Arrow then
Scan; -- past arrow
Identifier_OK := True;
-- Case of one of the special aspect forms
elsif Token = Tok_Apostrophe then
Scan; -- past apostrophe
-- We have apostrophe, so check for identifier'Class
if Token /= Tok_Identifier or else Token_Name /= Name_Class then
-- We have identifier'Class, check for arrow
Scan; -- Past Class
if Token /= Tok_Arrow then
-- Here we have scanned identifier'Class =>
Identifier_OK := True;
Scan; -- past arrow
case Chars (Identifier_Node) is
when Name_Pre =>
Set_Chars (Identifier_Node, Name_uPre);
when Name_Post =>
Set_Chars (Identifier_Node, Name_uPost);
when Name_Type_Invariant =>
Set_Chars (Identifier_Node, Name_uType_Invariant);
when Name_Invariant =>
Set_Chars (Identifier_Node, Name_uInvariant);
-- If it is X'Class => for some invalid X, we will give
-- an error, and forget that 'Class was present, which
-- will give better error recovery. We could do a spell
-- check here, but it seems too much work.
when others =>
Error_Msg_SC ("invalid aspect id for pragma");
end case;
end if;
end if;
end if;
-- Identifier was present
if Identifier_OK then
Set_Chars (Association, Chars (Identifier_Node));
Identifier_Seen := True;
-- Identifier not present after all
Restore_Scan_State (Scan_State); -- to Identifier
end if;
end if;
-- Diagnose error of "positional" argument for pragma appearing after
-- a "named" argument (quotes here are because that's not quite accurate
-- Ada RM terminology).
-- Since older GNAT versions did not generate this error, disable this
-- message in Relaxed_RM_Semantics mode to help legacy code using e.g.
-- codepeer.
if Identifier_Seen
and not Identifier_OK
and not Relaxed_RM_Semantics
Error_Msg_SC ("|pragma argument identifier required here");
Error_Msg_SC ("\since previous argument had identifier (RM 2.8(4))");
end if;
if Identifier_OK then
-- Certain pragmas such as Restriction_Warnings and Restrictions
-- allow reserved words to appear as expressions when checking for
-- prohibited uses of attributes.
if Reserved_Words_OK
and then Chars (Identifier_Node) = Name_No_Use_Of_Attribute
Expression_Node := P_Expression_Or_Reserved_Word;
Expression_Node := P_Expression;
end if;
Expression_Node := P_Expression_If_OK;
end if;
Set_Expression (Association, Expression_Node);
end Scan_Pragma_Argument_Association;
end Ch2;