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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- P A R . C H 6 --
-- --
-- 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. --
-- --
------------------------------------------------------------------------------
pragma Style_Checks (All_Checks);
-- Turn off subprogram body ordering check. Subprograms are in order
-- by RM section rather than alphabetical
with Sinfo.CN; use Sinfo.CN;
separate (Par)
package body Ch6 is
-- Local subprograms, used only in this chapter
function P_Defining_Designator return Node_Id;
function P_Defining_Operator_Symbol return Node_Id;
function P_Return_Object_Declaration return Node_Id;
procedure P_Return_Subtype_Indication (Decl_Node : Node_Id);
-- Decl_Node is a N_Object_Declaration. Set the Null_Exclusion_Present and
-- Object_Definition fields of Decl_Node.
procedure Check_Junk_Semicolon_Before_Return;
-- Check for common error of junk semicolon before RETURN keyword of
-- function specification. If present, skip over it with appropriate error
-- message, leaving Scan_Ptr pointing to the RETURN after. This routine
-- also deals with a possibly misspelled version of Return.
procedure No_Constraint_Maybe_Expr_Func;
-- Called after scanning return subtype to check for missing constraint,
-- taking into account the possibility of an occurrence of an expression
-- function where the IS has been forgotten.
----------------------------------------
-- Check_Junk_Semicolon_Before_Return --
----------------------------------------
procedure Check_Junk_Semicolon_Before_Return is
Scan_State : Saved_Scan_State;
begin
if Token = Tok_Semicolon then
Save_Scan_State (Scan_State);
Scan; -- past the semicolon
if Token = Tok_Return then
Restore_Scan_State (Scan_State);
Error_Msg_SC -- CODEFIX
("|extra "";"" ignored");
Scan; -- rescan past junk semicolon
else
Restore_Scan_State (Scan_State);
end if;
end if;
end Check_Junk_Semicolon_Before_Return;
-----------------------------------
-- No_Constraint_Maybe_Expr_Func --
-----------------------------------
procedure No_Constraint_Maybe_Expr_Func is
begin
-- If we have a left paren at the start of the line, then assume this is
-- the case of an expression function with missing IS. We do not have to
-- diagnose the missing IS, that is done elsewhere. We do this game in
-- Ada 2012 mode where expression functions are legal.
if Token = Tok_Left_Paren
and Ada_Version >= Ada_2012
and Token_Is_At_Start_Of_Line
then
-- One exception if we have "(token .." then this is a constraint
declare
Scan_State : Saved_Scan_State;
begin
Save_Scan_State (Scan_State);
Scan; -- past left paren
Scan; -- past following token
-- If we have "(token .." then restore scan state and treat as
-- unexpected constraint.
if Token = Tok_Dot_Dot then
Restore_Scan_State (Scan_State);
No_Constraint;
-- Otherwise we treat this as an expression function
else
Restore_Scan_State (Scan_State);
end if;
end;
-- Otherwise use standard routine to check for no constraint present
else
No_Constraint;
end if;
end No_Constraint_Maybe_Expr_Func;
-----------------------------------------------------
-- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
-----------------------------------------------------
-- This routine scans out a subprogram declaration, subprogram body,
-- subprogram renaming declaration or subprogram generic instantiation.
-- It also handles the new Ada 2012 expression function form
-- SUBPROGRAM_DECLARATION ::=
-- SUBPROGRAM_SPECIFICATION
-- [ASPECT_SPECIFICATIONS];
-- ABSTRACT_SUBPROGRAM_DECLARATION ::=
-- SUBPROGRAM_SPECIFICATION is abstract
-- [ASPECT_SPECIFICATIONS];
-- SUBPROGRAM_SPECIFICATION ::=
-- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
-- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
-- PARAMETER_PROFILE ::= [FORMAL_PART]
-- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
-- SUBPROGRAM_BODY ::=
-- SUBPROGRAM_SPECIFICATION [ASPECT_SPECIFICATIONS] is
-- DECLARATIVE_PART
-- begin
-- HANDLED_SEQUENCE_OF_STATEMENTS
-- end [DESIGNATOR];
-- SUBPROGRAM_RENAMING_DECLARATION ::=
-- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME
-- [ASPECT_SPECIFICATIONS];
-- SUBPROGRAM_BODY_STUB ::=
-- SUBPROGRAM_SPECIFICATION is separate
-- [ASPECT_SPECIFICATIONS];
-- GENERIC_INSTANTIATION ::=
-- procedure DEFINING_PROGRAM_UNIT_NAME is
-- new generic_procedure_NAME [GENERIC_ACTUAL_PART]
-- [ASPECT_SPECIFICATIONS];
-- | function DEFINING_DESIGNATOR is
-- new generic_function_NAME [GENERIC_ACTUAL_PART]
-- [ASPECT_SPECIFICATIONS];
-- NULL_PROCEDURE_DECLARATION ::=
-- SUBPROGRAM_SPECIFICATION is null;
-- Null procedures are an Ada 2005 feature. A null procedure declaration
-- is classified as a basic declarative item, but it is parsed here, with
-- other subprogram constructs.
-- EXPRESSION_FUNCTION ::=
-- FUNCTION SPECIFICATION IS (EXPRESSION)
-- [ASPECT_SPECIFICATIONS];
-- The caller has checked that the initial token is FUNCTION, PROCEDURE,
-- NOT or OVERRIDING.
-- Error recovery: cannot raise Error_Resync
function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
function Contains_Import_Aspect (Aspects : List_Id) return Boolean;
-- Return True if Aspects contains an Import aspect.
----------------------------
-- Contains_Import_Aspect --
----------------------------
function Contains_Import_Aspect (Aspects : List_Id) return Boolean is
Aspect : Node_Id := First (Aspects);
begin
while Present (Aspect) loop
if Chars (Identifier (Aspect)) = Name_Import then
return True;
end if;
Next (Aspect);
end loop;
return False;
end Contains_Import_Aspect;
Specification_Node : Node_Id;
Name_Node : Node_Id;
Aspects : List_Id;
Fpart_List : List_Id;
Fpart_Sloc : Source_Ptr;
Result_Not_Null : Boolean := False;
Result_Node : Node_Id;
Inst_Node : Node_Id;
Body_Node : Node_Id;
Decl_Node : Node_Id;
Rename_Node : Node_Id;
Absdec_Node : Node_Id;
Stub_Node : Node_Id;
Fproc_Sloc : Source_Ptr;
Func : Boolean;
Scan_State : Saved_Scan_State;
-- Flags for optional overriding indication. Two flags are needed,
-- to distinguish positive and negative overriding indicators from
-- the absence of any indicator.
Is_Overriding : Boolean := False;
Not_Overriding : Boolean := False;
begin
-- Set up scope stack entry. Note that the Labl field will be set later
SIS_Entry_Active := False;
SIS_Aspect_Import_Seen := False;
SIS_Missing_Semicolon_Message := No_Error_Msg;
Push_Scope_Stack;
Scopes (Scope.Last).Sloc := Token_Ptr;
Scopes (Scope.Last).Etyp := E_Name;
Scopes (Scope.Last).Ecol := Start_Column;
Scopes (Scope.Last).Lreq := False;
Aspects := Empty_List;
-- Ada 2005: Scan leading NOT OVERRIDING indicator
if Token = Tok_Not then
Scan; -- past NOT
if Token = Tok_Overriding then
Scan; -- past OVERRIDING
Not_Overriding := True;
-- Overriding keyword used in non Ada 2005 mode
elsif Token = Tok_Identifier
and then Token_Name = Name_Overriding
then
Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
Scan; -- past Overriding
Not_Overriding := True;
else
Error_Msg_SC -- CODEFIX
("OVERRIDING expected!");
end if;
-- Ada 2005: scan leading OVERRIDING indicator
-- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
-- declaration circuit already gave an error message and changed the
-- token to Tok_Overriding.
elsif Token = Tok_Overriding then
Scan; -- past OVERRIDING
Is_Overriding := True;
end if;
if Is_Overriding or else Not_Overriding then
-- Note that if we are not in Ada_2005 mode, error messages have
-- already been given, so no need to give another message here.
-- An overriding indicator is allowed for subprogram declarations,
-- bodies (including subunits), renamings, stubs, and instantiations.
-- The test against Pf_Decl_Pbod is added to account for the case of
-- subprograms declared in a protected type, where only subprogram
-- declarations and bodies can occur. The Pf_Pbod case is for
-- subunits.
if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp
and then
Pf_Flags /= Pf_Decl_Pbod_Pexp
and then
Pf_Flags /= Pf_Pbod_Pexp
then
Error_Msg_SC ("overriding indicator not allowed here!");
elsif Token not in Tok_Function | Tok_Procedure then
Error_Msg_SC -- CODEFIX
("FUNCTION or PROCEDURE expected!");
end if;
end if;
Func := (Token = Tok_Function);
Fproc_Sloc := Token_Ptr;
Scan; -- past FUNCTION or PROCEDURE
Ignore (Tok_Type);
Ignore (Tok_Body);
if Func then
Name_Node := P_Defining_Designator;
if Nkind (Name_Node) = N_Defining_Operator_Symbol
and then Scope.Last = 1
then
Error_Msg_SP ("operator symbol not allowed at library level");
Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
-- Set name from file name, we need some junk name, and that's
-- as good as anything. This is only approximate, since we do
-- not do anything with non-standard name translations.
Get_Name_String (File_Name (Current_Source_File));
for J in 1 .. Name_Len loop
if Name_Buffer (J) = '.' then
Name_Len := J - 1;
exit;
end if;
end loop;
Set_Chars (Name_Node, Name_Find);
Set_Error_Posted (Name_Node);
end if;
else
Name_Node := P_Defining_Program_Unit_Name;
end if;
Scopes (Scope.Last).Labl := Name_Node;
Current_Node := Name_Node;
Ignore (Tok_Colon);
-- Deal with generic instantiation, the one case in which we do not
-- have a subprogram specification as part of whatever we are parsing
if Token = Tok_Is then
Save_Scan_State (Scan_State); -- at the IS
T_Is; -- checks for redundant IS
if Token = Tok_New then
if not Pf_Flags.Gins then
Error_Msg_SC ("generic instantiation not allowed here!");
end if;
Scan; -- past NEW
if Func then
Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
Set_Name (Inst_Node, P_Function_Name);
else
Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
Set_Name (Inst_Node, P_Qualified_Simple_Name);
end if;
Set_Defining_Unit_Name (Inst_Node, Name_Node);
Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
P_Aspect_Specifications (Inst_Node);
Pop_Scope_Stack; -- Don't need scope stack entry in this case
if Is_Overriding then
Set_Must_Override (Inst_Node);
elsif Not_Overriding then
Set_Must_Not_Override (Inst_Node);
end if;
return Inst_Node;
else
Restore_Scan_State (Scan_State); -- to the IS
end if;
end if;
-- If not a generic instantiation, then we definitely have a subprogram
-- specification (all possibilities at this stage include one here)
Fpart_Sloc := Token_Ptr;
Check_Misspelling_Of (Tok_Return);
-- Scan formal part. First a special error check. If we have an
-- identifier here, then we have a definite error. If this identifier
-- is on the same line as the designator, then we assume it is the
-- first formal after a missing left parenthesis
if Token = Tok_Identifier
and then not Token_Is_At_Start_Of_Line
then
T_Left_Paren; -- to generate message
Fpart_List := P_Formal_Part;
-- Otherwise scan out an optional formal part in the usual manner
else
Fpart_List := P_Parameter_Profile;
end if;
-- We treat what we have as a function specification if FUNCTION was
-- used, or if a RETURN is present. This gives better error recovery
-- since later RETURN statements will be valid in either case.
Check_Junk_Semicolon_Before_Return;
Result_Node := Error;
if Token = Tok_Return then
if not Func then
Error_Msg -- CODEFIX
("PROCEDURE should be FUNCTION", Fproc_Sloc);
Func := True;
end if;
Scan; -- past RETURN
Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
-- Ada 2005 (AI-318-02)
if Token = Tok_Access then
Error_Msg_Ada_2005_Extension ("anonymous access result type");
Result_Node := P_Access_Definition (Result_Not_Null);
else
Result_Node := P_Subtype_Mark;
No_Constraint_Maybe_Expr_Func;
end if;
else
-- Skip extra parenthesis at end of formal part
Ignore (Tok_Right_Paren);
-- For function, scan result subtype
if Func then
TF_Return;
if Prev_Token = Tok_Return then
Result_Node := P_Subtype_Mark;
end if;
end if;
end if;
if Func then
Specification_Node :=
New_Node (N_Function_Specification, Fproc_Sloc);
Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
Set_Result_Definition (Specification_Node, Result_Node);
else
Specification_Node :=
New_Node (N_Procedure_Specification, Fproc_Sloc);
end if;
Set_Defining_Unit_Name (Specification_Node, Name_Node);
Set_Parameter_Specifications (Specification_Node, Fpart_List);
if Is_Overriding then
Set_Must_Override (Specification_Node);
elsif Not_Overriding then
Set_Must_Not_Override (Specification_Node);
end if;
-- Error check: barriers not allowed on protected functions/procedures
if Token = Tok_When then
if Func then
Error_Msg_SC ("barrier not allowed on function, only on entry");
else
Error_Msg_SC ("barrier not allowed on procedure, only on entry");
end if;
Scan; -- past WHEN
Discard_Junk_Node (P_Expression);
end if;
-- Deal with semicolon followed by IS. We want to treat this as IS
if Token = Tok_Semicolon then
Save_Scan_State (Scan_State);
Scan; -- past semicolon
if Token = Tok_Is then
Error_Msg_SP -- CODEFIX
("extra "";"" ignored");
else
Restore_Scan_State (Scan_State);
end if;
end if;
-- Subprogram declaration ended by aspect specifications
if Aspect_Specifications_Present then
goto Subprogram_Declaration;
-- Deal with case of semicolon ending a subprogram declaration
elsif Token = Tok_Semicolon then
if not Pf_Flags.Decl then
T_Is;
end if;
Save_Scan_State (Scan_State);
Scan; -- past semicolon
-- If semicolon is immediately followed by IS, then ignore the
-- semicolon, and go process the body.
if Token = Tok_Is then
Error_Msg_SP -- CODEFIX
("|extra "";"" ignored");
T_Is; -- scan past IS
goto Subprogram_Body;
-- If BEGIN follows in an appropriate column, we immediately
-- commence the error action of assuming that the previous
-- subprogram declaration should have been a subprogram body,
-- i.e. that the terminating semicolon should have been IS.
elsif Token = Tok_Begin
and then Start_Column >= Scopes (Scope.Last).Ecol
then
Error_Msg_SP -- CODEFIX
("|"";"" should be IS!");
goto Subprogram_Body;
else
Restore_Scan_State (Scan_State);
goto Subprogram_Declaration;
end if;
-- Case of not followed by semicolon
else
-- Subprogram renaming declaration case
Check_Misspelling_Of (Tok_Renames);
if Token = Tok_Renames then
if not Pf_Flags.Rnam then
Error_Msg_SC ("renaming declaration not allowed here!");
end if;
Rename_Node :=
New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
Scan; -- past RENAMES
Set_Name (Rename_Node, P_Name);
Set_Specification (Rename_Node, Specification_Node);
P_Aspect_Specifications (Rename_Node);
TF_Semicolon;
Pop_Scope_Stack;
return Rename_Node;
-- Case of IS following subprogram specification
elsif Token = Tok_Is then
T_Is; -- ignore redundant Is's
if Token_Name = Name_Abstract then
Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
end if;
-- Deal nicely with (now obsolete) use of <> in place of abstract
if Token = Tok_Box then
Error_Msg_SC -- CODEFIX
("ABSTRACT expected");
Token := Tok_Abstract;
end if;
-- Abstract subprogram declaration case
if Token = Tok_Abstract then
Absdec_Node :=
New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
Set_Specification (Absdec_Node, Specification_Node);
Pop_Scope_Stack; -- discard unneeded entry
Scan; -- past ABSTRACT
P_Aspect_Specifications (Absdec_Node);
return Absdec_Node;
-- Ada 2005 (AI-248): Parse a null procedure declaration
elsif Token = Tok_Null then
Error_Msg_Ada_2005_Extension ("null procedure");
Scan; -- past NULL
if Func then
Error_Msg_SP ("only procedures can be null");
else
Set_Null_Present (Specification_Node);
Set_Null_Statement (Specification_Node,
New_Node (N_Null_Statement, Prev_Token_Ptr));
end if;
goto Subprogram_Declaration;
-- Check for IS NEW with Formal_Part present and handle nicely
elsif Token = Tok_New then
Error_Msg
("formal part not allowed in instantiation", Fpart_Sloc);
Scan; -- past NEW
if Func then
Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
else
Inst_Node :=
New_Node (N_Procedure_Instantiation, Fproc_Sloc);
end if;
Set_Defining_Unit_Name (Inst_Node, Name_Node);
Set_Name (Inst_Node, P_Name);
Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
TF_Semicolon;
Pop_Scope_Stack; -- Don't need scope stack entry in this case
return Inst_Node;
else
goto Subprogram_Body;
end if;
-- Aspect specifications present
elsif Aspect_Specifications_Present then
goto Subprogram_Declaration;
-- Here we have a missing IS or missing semicolon
else
-- If the next token is a left paren at the start of a line, then
-- this is almost certainly the start of the expression for an
-- expression function, so in this case guess a missing IS.
if Token = Tok_Left_Paren and then Token_Is_At_Start_Of_Line then
Error_Msg_AP -- CODEFIX
("missing IS");
-- In all other cases, we guess a missing semicolon, since we are
-- good at fixing up a semicolon which should really be an IS.
else
Error_Msg_AP -- CODEFIX
("|missing "";""");
SIS_Missing_Semicolon_Message := Get_Msg_Id;
goto Subprogram_Declaration;
end if;
end if;
end if;
-- Processing for stub or subprogram body or expression function
<<Subprogram_Body>>
-- Subprogram body stub case
if Separate_Present then
if not Pf_Flags.Stub then
Error_Msg_SC ("body stub not allowed here!");
end if;
if Nkind (Name_Node) = N_Defining_Operator_Symbol then
Error_Msg
("operator symbol cannot be used as subunit name",
Sloc (Name_Node));
end if;
Scan; -- past SEPARATE
Stub_Node :=
New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
Set_Specification (Stub_Node, Specification_Node);
if Is_Non_Empty_List (Aspects) then
Error_Msg
("aspect specifications must come after SEPARATE",
Sloc (First (Aspects)));
end if;
P_Aspect_Specifications (Stub_Node, Semicolon => False);
TF_Semicolon;
Pop_Scope_Stack;
return Stub_Node;
-- Subprogram body or expression function case
else
Scan_Body_Or_Expression_Function : declare
function Likely_Expression_Function return Boolean;
-- Returns True if we have a probable case of an expression
-- function omitting the parentheses, if so, returns True
-- and emits an appropriate error message, else returns False.
--------------------------------
-- Likely_Expression_Function --
--------------------------------
function Likely_Expression_Function return Boolean is
begin
-- If currently pointing to BEGIN or a declaration keyword
-- or a pragma, then we definitely have a subprogram body.
-- This is a common case, so worth testing first.
if Token in Tok_Begin | Token_Class_Declk | Tok_Pragma then
return False;
-- Test for tokens which could only start an expression and
-- thus signal the case of a expression function.
elsif Token in
Token_Class_Literal | Token_Class_Unary_Addop |
Tok_Left_Paren | Tok_Abs | Tok_Null | Tok_New | Tok_Not
then
null;
-- Anything other than an identifier must be a body
elsif Token /= Tok_Identifier then
return False;
-- Here for an identifier
else
-- If the identifier is the first token on its line, then
-- let's assume that we have a missing begin and this is
-- intended as a subprogram body. However, if the context
-- is a function and the unit is a package declaration, a
-- body would be illegal, so try for an unparenthesized
-- expression function.
if Token_Is_At_Start_Of_Line then
declare
-- The enclosing scope entry is a subprogram spec
Spec_Node : constant Node_Id :=
Parent
(Scopes (Scope.Last).Labl);
Lib_Node : Node_Id := Spec_Node;
begin
-- Check whether there is an enclosing scope that
-- is a package declaration.
if Scope.Last > 1 then
Lib_Node :=
Parent (Scopes (Scope.Last - 1).Labl);
end if;
if Ada_Version >= Ada_2012
and then
Nkind (Lib_Node) = N_Package_Specification
and then
Nkind (Spec_Node) = N_Function_Specification
then
null;
else
return False;
end if;
end;
-- Otherwise we have to scan ahead. If the identifier is
-- followed by a colon or a comma, it is a declaration
-- and hence we have a subprogram body. Otherwise assume
-- a expression function.
else
declare
Scan_State : Saved_Scan_State;
Tok : Token_Type;
begin
Save_Scan_State (Scan_State);
Scan; -- past identifier
Tok := Token;
Restore_Scan_State (Scan_State);
if Tok = Tok_Colon or else Tok = Tok_Comma then
return False;
end if;
end;
end if;
end if;
-- Fall through if we have a likely expression function.
-- If the starting keyword is not "function" the error
-- will be reported elsewhere.
if Func then
Error_Msg_SC
("expression function must be enclosed in parentheses");
end if;
return True;
end Likely_Expression_Function;
-- Start of processing for Scan_Body_Or_Expression_Function
begin
-- Expression_Function case
-- If likely an aggregate, check we are in Ada 2022 mode
if Token = Tok_Left_Bracket then
Error_Msg_Ada_2022_Feature
("!aggregates as expression function", Token_Ptr);
end if;
if Token in Tok_Left_Paren | Tok_Left_Bracket
or else Likely_Expression_Function
then
-- Check expression function allowed here
if not Pf_Flags.Pexp then
Error_Msg_SC ("expression function not allowed here!");
end if;
-- Check we are in Ada 2012 mode
Error_Msg_Ada_2012_Feature
("!expression function", Token_Ptr);
-- Catch an illegal placement of the aspect specification
-- list:
-- function_specification
-- [aspect_specification] is (expression);
-- This case is correctly processed by the parser because
-- the expression function first appears as a subprogram
-- declaration to the parser. The starting keyword may
-- not have been "function" in which case the error is
-- on a malformed procedure.
if Is_Non_Empty_List (Aspects) then
if Func then
Error_Msg
("aspect specifications must come after "
& "parenthesized expression",
Sloc (First (Aspects)));
else
Error_Msg
("aspect specifications must come after subprogram "
& "specification", Sloc (First (Aspects)));
end if;
end if;
-- Parse out expression and build expression function
Body_Node :=
New_Node
(N_Expression_Function, Sloc (Specification_Node));
Set_Specification (Body_Node, Specification_Node);
declare
Expr : constant Node_Id := P_Expression;
begin
Set_Expression (Body_Node, Expr);
-- Check that the full expression is properly
-- parenthesized since we may have a left-operand that is
-- parenthesized but that is not one of the allowed cases
-- with syntactic parentheses.
if not (Paren_Count (Expr) /= 0
or else Nkind (Expr) in N_Aggregate
| N_Extension_Aggregate
| N_Quantified_Expression)
then
Error_Msg
("expression function must be enclosed in "
& "parentheses", Sloc (Expr));
end if;
end;
-- Expression functions can carry pre/postconditions
P_Aspect_Specifications (Body_Node);
Pop_Scope_Stack;
-- Subprogram body case
else
-- Check body allowed here
if not Pf_Flags.Pbod then
Error_Msg_SP ("subprogram body not allowed here!");
end if;
-- Here is the test for a suspicious IS (i.e. one that
-- looks like it might more properly be a semicolon).
-- See separate section describing use of IS instead
-- of semicolon in package Parse.
if (Token in Token_Class_Declk
or else
Token = Tok_Identifier)
and then Start_Column <= Scopes (Scope.Last).Ecol
and then Scope.Last /= 1
then
Scopes (Scope.Last).Etyp := E_Suspicious_Is;
Scopes (Scope.Last).S_Is := Prev_Token_Ptr;
end if;
-- Build and return subprogram body, parsing declarations
-- and statement sequence that belong to the body.
Body_Node :=
New_Node (N_Subprogram_Body, Sloc (Specification_Node));
Set_Specification (Body_Node, Specification_Node);
-- If aspects are present, the specification is parsed as
-- a subprogram declaration, and we jump here after seeing
-- the keyword IS. Attach asspects previously collected to
-- the body.
if Is_Non_Empty_List (Aspects) then
Set_Parent (Aspects, Body_Node);
Set_Aspect_Specifications (Body_Node, Aspects);
end if;
Parse_Decls_Begin_End (Body_Node);
end if;
return Body_Node;
end Scan_Body_Or_Expression_Function;
end if;
-- Processing for subprogram declaration
<<Subprogram_Declaration>>
Decl_Node :=
New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
Set_Specification (Decl_Node, Specification_Node);
Aspects := Get_Aspect_Specifications (Semicolon => False);
-- Aspects may be present on a subprogram body. The source parsed
-- so far is that of its specification. Go parse the body and attach
-- the collected aspects, if any, to the body.
if Token = Tok_Is then
-- If the subprogram is a procedure and already has a
-- specification, we can't define another.
if Nkind (Specification (Decl_Node)) = N_Procedure_Specification
and then Null_Present (Specification (Decl_Node))
then
Error_Msg_AP ("null procedure cannot have a body");
end if;
Scan;
goto Subprogram_Body;
else
if Is_Non_Empty_List (Aspects) then
Set_Parent (Aspects, Decl_Node);
Set_Aspect_Specifications (Decl_Node, Aspects);
end if;
TF_Semicolon;
end if;
-- If this is a context in which a subprogram body is permitted,
-- set active SIS entry in case (see section titled "Handling
-- Semicolon Used in Place of IS" in body of Parser package)
-- Note that SIS_Missing_Semicolon_Message is already set properly.
if Pf_Flags.Pbod
-- Disconnect this processing if we have scanned a null procedure
-- or an Import aspect because in this case the spec is complete
-- anyway with no body.
and then (Nkind (Specification_Node) /= N_Procedure_Specification
or else not Null_Present (Specification_Node))
and then not Contains_Import_Aspect (Aspects)
then
SIS_Labl := Scopes (Scope.Last).Labl;
SIS_Sloc := Scopes (Scope.Last).Sloc;
SIS_Ecol := Scopes (Scope.Last).Ecol;
SIS_Declaration_Node := Decl_Node;
SIS_Semicolon_Sloc := Prev_Token_Ptr;
-- Do not activate the entry if we have "with Import"
if not SIS_Aspect_Import_Seen then
SIS_Entry_Active := True;
end if;
end if;
Pop_Scope_Stack;
return Decl_Node;
end P_Subprogram;
---------------------------------
-- 6.1 Subprogram Declaration --
---------------------------------
-- Parsed by P_Subprogram (6.1)
------------------------------------------
-- 6.1 Abstract Subprogram Declaration --
------------------------------------------
-- Parsed by P_Subprogram (6.1)
-----------------------------------
-- 6.1 Subprogram Specification --
-----------------------------------
-- SUBPROGRAM_SPECIFICATION ::=
-- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
-- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
-- PARAMETER_PROFILE ::= [FORMAL_PART]
-- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
-- Subprogram specifications that appear in subprogram declarations
-- are parsed by P_Subprogram (6.1). This routine is used in other
-- contexts where subprogram specifications occur.
-- Note: this routine does not affect the scope stack in any way
-- Error recovery: can raise Error_Resync
function P_Subprogram_Specification return Node_Id is
Specification_Node : Node_Id;
Result_Not_Null : Boolean;
Result_Node : Node_Id;
begin
if Token = Tok_Function then
Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
Scan; -- past FUNCTION
Ignore (Tok_Body);
Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
Set_Parameter_Specifications
(Specification_Node, P_Parameter_Profile);
Check_Junk_Semicolon_Before_Return;
TF_Return;
Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
-- Ada 2005 (AI-318-02)
if Token = Tok_Access then
Error_Msg_Ada_2005_Extension ("anonymous access result type");
Result_Node := P_Access_Definition (Result_Not_Null);
else
Result_Node := P_Subtype_Mark;
No_Constraint_Maybe_Expr_Func;
end if;
Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
Set_Result_Definition (Specification_Node, Result_Node);
return Specification_Node;
elsif Token = Tok_Procedure then
Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
Scan; -- past PROCEDURE
Ignore (Tok_Body);
Set_Defining_Unit_Name
(Specification_Node, P_Defining_Program_Unit_Name);
Set_Parameter_Specifications
(Specification_Node, P_Parameter_Profile);
return Specification_Node;
else
Error_Msg_SC ("subprogram specification expected");
raise Error_Resync;
end if;
end P_Subprogram_Specification;
---------------------
-- 6.1 Designator --
---------------------
-- DESIGNATOR ::=
-- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
-- The caller has checked that the initial token is an identifier,
-- operator symbol, or string literal. Note that we don't bother to
-- do much error diagnosis in this routine, since it is only used for
-- the label on END lines, and the routines in package Par.Endh will
-- check that the label is appropriate.
-- Error recovery: cannot raise Error_Resync
function P_Designator return Node_Id is
Ident_Node : Node_Id;
Name_Node : Node_Id;
Prefix_Node : Node_Id;
function Real_Dot return Boolean;
-- Tests if a current token is an interesting period, i.e. is followed
-- by an identifier or operator symbol or string literal. If not, it is
-- probably just incorrect punctuation to be caught by our caller. Note
-- that the case of an operator symbol or string literal is also an
-- error, but that is an error that we catch here. If the result is
-- True, a real dot has been scanned and we are positioned past it,
-- if the result is False, the scan position is unchanged.
--------------
-- Real_Dot --
--------------
function Real_Dot return Boolean is
Scan_State : Saved_Scan_State;
begin
if Token /= Tok_Dot then
return False;
else
Save_Scan_State (Scan_State);
Scan; -- past dot
if Token in
Tok_Identifier | Tok_Operator_Symbol | Tok_String_Literal
then
return True;
else
Restore_Scan_State (Scan_State);
return False;
end if;
end if;
end Real_Dot;
-- Start of processing for P_Designator
begin
Ident_Node := Token_Node;
Scan; -- past initial token
if Prev_Token in Tok_Operator_Symbol | Tok_String_Literal
or else not Real_Dot
then
return Ident_Node;
-- Child name case
else
Prefix_Node := Ident_Node;
-- Loop through child names, on entry to this loop, Prefix contains
-- the name scanned so far, and Ident_Node is the last identifier.
loop
Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
Set_Prefix (Name_Node, Prefix_Node);
Ident_Node := P_Identifier;
Set_Selector_Name (Name_Node, Ident_Node);
Prefix_Node := Name_Node;
exit when not Real_Dot;
end loop;
-- On exit from the loop, Ident_Node is the last identifier scanned,
-- i.e. the defining identifier, and Prefix_Node is a node for the
-- entire name, structured (incorrectly) as a selected component.
Name_Node := Prefix (Prefix_Node);
Change_Node (Prefix_Node, N_Designator);
Set_Name (Prefix_Node, Name_Node);
Set_Identifier (Prefix_Node, Ident_Node);
return Prefix_Node;
end if;
exception
when Error_Resync =>
while Token in Tok_Dot | Tok_Identifier loop
Scan;
end loop;
return Error;
end P_Designator;
------------------------------
-- 6.1 Defining Designator --
------------------------------
-- DEFINING_DESIGNATOR ::=
-- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
-- Error recovery: cannot raise Error_Resync
function P_Defining_Designator return Node_Id is
begin
if Token = Tok_Operator_Symbol then
return P_Defining_Operator_Symbol;
elsif Token = Tok_String_Literal then
Error_Msg_SC ("invalid operator name");
Scan; -- past junk string
return Error;
else
return P_Defining_Program_Unit_Name;
end if;
end P_Defining_Designator;
-------------------------------------
-- 6.1 Defining Program Unit Name --
-------------------------------------
-- DEFINING_PROGRAM_UNIT_NAME ::=
-- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
-- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
-- Error recovery: cannot raise Error_Resync
function P_Defining_Program_Unit_Name return Node_Id is
Ident_Node : Node_Id;
Name_Node : Node_Id;
Prefix_Node : Node_Id;
begin
-- Set identifier casing if not already set and scan initial identifier
if Token = Tok_Identifier
and then Identifier_Casing (Current_Source_File) = Unknown
then
Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
end if;
Ident_Node := P_Identifier (C_Dot);
Merge_Identifier (Ident_Node, Tok_Return);
-- Normal case (not child library unit name)
if Token /= Tok_Dot then
Change_Identifier_To_Defining_Identifier (Ident_Node);
Warn_If_Standard_Redefinition (Ident_Node);
return Ident_Node;
-- Child library unit name case
else
if Scope.Last > 1 then
Error_Msg_SP ("child unit allowed only at library level");
raise Error_Resync;
elsif Ada_Version = Ada_83 then
Error_Msg_SP ("(Ada 83) child unit not allowed!");
end if;
Prefix_Node := Ident_Node;
-- Loop through child names, on entry to this loop, Prefix contains
-- the name scanned so far, and Ident_Node is the last identifier.
loop
exit when Token /= Tok_Dot;
Name_Node := New_Node (N_Selected_Component, Token_Ptr);
Scan; -- past period
Set_Prefix (Name_Node, Prefix_Node);
Ident_Node := P_Identifier (C_Dot);
Set_Selector_Name (Name_Node, Ident_Node);
Prefix_Node := Name_Node;
end loop;
-- On exit from the loop, Ident_Node is the last identifier scanned,
-- i.e. the defining identifier, and Prefix_Node is a node for the
-- entire name, structured (incorrectly) as a selected component.
Name_Node := Prefix (Prefix_Node);
Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
Set_Name (Prefix_Node, Name_Node);
Change_Identifier_To_Defining_Identifier (Ident_Node);
Warn_If_Standard_Redefinition (Ident_Node);
Set_Defining_Identifier (Prefix_Node, Ident_Node);
-- All set with unit name parsed
return Prefix_Node;
end if;
exception
when Error_Resync =>
while Token in Tok_Dot | Tok_Identifier loop
Scan;
end loop;
return Error;
end P_Defining_Program_Unit_Name;
--------------------------
-- 6.1 Operator Symbol --
--------------------------
-- OPERATOR_SYMBOL ::= STRING_LITERAL
-- Operator symbol is returned by the scanner as Tok_Operator_Symbol
-----------------------------------
-- 6.1 Defining Operator Symbol --
-----------------------------------
-- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
-- The caller has checked that the initial symbol is an operator symbol
function P_Defining_Operator_Symbol return Node_Id is
Op_Node : Node_Id;
begin
Op_Node := Token_Node;
Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
Scan; -- past operator symbol
return Op_Node;
end P_Defining_Operator_Symbol;
----------------------------
-- 6.1 Parameter_Profile --
----------------------------
-- PARAMETER_PROFILE ::= [FORMAL_PART]
-- Empty is returned if no formal part is present
-- Error recovery: cannot raise Error_Resync
function P_Parameter_Profile return List_Id is
begin
if Token = Tok_Left_Paren then
Scan; -- part left paren
return P_Formal_Part;
else
return No_List;
end if;
end P_Parameter_Profile;
---------------------------------------
-- 6.1 Parameter And Result Profile --
---------------------------------------
-- Parsed by its parent construct, which uses P_Parameter_Profile to
-- parse the parameters, and P_Subtype_Mark to parse the return type.
----------------------
-- 6.1 Formal part --
----------------------
-- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
-- PARAMETER_SPECIFICATION ::=
-- DEFINING_IDENTIFIER_LIST : [ALIASED] MODE [NULL_EXCLUSION]
-- SUBTYPE_MARK [:= DEFAULT_EXPRESSION]
-- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
-- [:= DEFAULT_EXPRESSION]
-- This scans the construct Formal_Part. The caller has already checked
-- that the initial token is a left parenthesis, and skipped past it, so
-- that on entry Token is the first token following the left parenthesis.
-- Note: The ALIASED keyword is allowed only in Ada 2012 mode (AI 142)
-- Error recovery: cannot raise Error_Resync
function P_Formal_Part return List_Id is
Specification_List : List_Id;
Specification_Node : Node_Id;
Scan_State : Saved_Scan_State;
Num_Idents : Nat;
Ident : Nat;
Ident_Sloc : Source_Ptr;
Not_Null_Present : Boolean := False;
Not_Null_Sloc : Source_Ptr;
Idents : array (Int range 1 .. 4096) of Entity_Id;
-- This array holds the list of defining identifiers. The upper bound
-- of 4096 is intended to be essentially infinite, and we do not even
-- bother to check for it being exceeded.
begin
Specification_List := New_List;
Specification_Loop : loop
begin
if Token = Tok_Pragma then
Error_Msg_SC ("pragma not allowed in formal part");
Discard_Junk_Node (P_Pragma (Skipping => True));
end if;
Ignore (Tok_Left_Paren);
Ident_Sloc := Token_Ptr;
Idents (1) := P_Defining_Identifier (C_Comma_Colon);
Num_Idents := 1;
Ident_Loop : loop
exit Ident_Loop when Token = Tok_Colon;
-- The only valid tokens are colon and comma, so if we have
-- neither do a bit of investigation to see which is the
-- better choice for insertion.
if Token /= Tok_Comma then
-- Assume colon if ALIASED, IN or OUT keyword found
exit Ident_Loop when Token = Tok_Aliased or else
Token = Tok_In or else
Token = Tok_Out;
-- Otherwise scan ahead
Save_Scan_State (Scan_State);
Look_Ahead : loop
-- If we run into a semicolon, then assume that a
-- colon was missing, e.g. Parms (X Y; ...). Also
-- assume missing colon on EOF (a real disaster)
-- and on a right paren, e.g. Parms (X Y), and also
-- on an assignment symbol, e.g. Parms (X Y := ..)
if Token in Tok_Semicolon | Tok_Right_Paren |
Tok_EOF | Tok_Colon_Equal
then
Restore_Scan_State (Scan_State);
exit Ident_Loop;
-- If we run into a colon, assume that we had a missing
-- comma, e.g. Parms (A B : ...). Also assume a missing
-- comma if we hit another comma, e.g. Parms (A B, C ..)
elsif Token in Tok_Colon | Tok_Comma then
Restore_Scan_State (Scan_State);
exit Look_Ahead;
end if;
Scan;
end loop Look_Ahead;
end if;
-- Here if a comma is present, or to be assumed
T_Comma;
Num_Idents := Num_Idents + 1;
Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
end loop Ident_Loop;
-- Fall through the loop on encountering a colon, or deciding
-- that there is a missing colon.
T_Colon;
-- If there are multiple identifiers, we repeatedly scan the
-- type and initialization expression information by resetting
-- the scan pointer (so that we get completely separate trees
-- for each occurrence).
if Num_Idents > 1 then
Save_Scan_State (Scan_State);
end if;
-- Loop through defining identifiers in list
Ident := 1;
Ident_List_Loop : loop
Specification_Node :=
New_Node (N_Parameter_Specification, Ident_Sloc);
Set_Defining_Identifier (Specification_Node, Idents (Ident));
-- Scan possible ALIASED for Ada 2012 (AI-142)
if Token = Tok_Aliased then
if Ada_Version < Ada_2012 then
Error_Msg_Ada_2012_Feature
("ALIASED parameter", Token_Ptr);
else
Set_Aliased_Present (Specification_Node);
end if;
Scan; -- past ALIASED
end if;
-- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
Not_Null_Sloc := Token_Ptr;
Not_Null_Present :=
P_Null_Exclusion (Allow_Anonymous_In_95 => True);
-- Case of ACCESS keyword present
if Token = Tok_Access then
Set_Null_Exclusion_Present
(Specification_Node, Not_Null_Present);
if Ada_Version = Ada_83 then
Error_Msg_SC ("(Ada 83) access parameters not allowed");
end if;
Set_Parameter_Type
(Specification_Node,
P_Access_Definition (Not_Null_Present));
-- Case of IN or OUT present
else
if Token in Tok_In | Tok_Out then
if Not_Null_Present then
Error_Msg
("`NOT NULL` can only be used with `ACCESS`",
Not_Null_Sloc);
if Token = Tok_In then
Error_Msg
("\`IN` not allowed together with `ACCESS`",
Not_Null_Sloc);
else
Error_Msg
("\`OUT` not allowed together with `ACCESS`",
Not_Null_Sloc);
end if;
end if;
P_Mode (Specification_Node);
Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
end if;
Set_Null_Exclusion_Present
(Specification_Node, Not_Null_Present);
if Token = Tok_Procedure
or else
Token = Tok_Function
then
Error_Msg_SC ("formal subprogram parameter not allowed");
Scan;
if Token = Tok_Left_Paren then
Discard_Junk_List (P_Formal_Part);
end if;
if Token = Tok_Return then
Scan;
Discard_Junk_Node (P_Subtype_Mark);
end if;
Set_Parameter_Type (Specification_Node, Error);
else
Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
No_Constraint;
end if;
end if;
Set_Expression (Specification_Node, Init_Expr_Opt (True));
if Ident > 1 then
Set_Prev_Ids (Specification_Node, True);
end if;
if Ident < Num_Idents then
Set_More_Ids (Specification_Node, True);
end if;
Append (Specification_Node, Specification_List);
exit Ident_List_Loop when Ident = Num_Idents;
Ident := Ident + 1;
Restore_Scan_State (Scan_State);
end loop Ident_List_Loop;
exception
when Error_Resync =>
Resync_Semicolon_List;
end;
if Token = Tok_Semicolon then
Save_Scan_State (Scan_State);
Scan; -- past semicolon
-- If we have RETURN or IS after the semicolon, then assume
-- that semicolon should have been a right parenthesis and exit
if Token in Tok_Is | Tok_Return then
Error_Msg_SP -- CODEFIX
("|"";"" should be "")""");
exit Specification_Loop;
end if;
-- If we have a declaration keyword after the semicolon, then
-- assume we had a missing right parenthesis and terminate list
if Token in Token_Class_Declk then
Error_Msg_AP -- CODEFIX
("missing "")""");
Restore_Scan_State (Scan_State);
exit Specification_Loop;
end if;
elsif Token = Tok_Right_Paren then
Scan; -- past right paren
exit Specification_Loop;
-- Support for aspects on formal parameters is a GNAT extension for
-- the time being.
elsif Token = Tok_With then
Error_Msg_Ada_2022_Feature
("aspect on formal parameter", Token_Ptr);
P_Aspect_Specifications (Specification_Node, False);
-- Set the aspect specifications for previous Ids
if Has_Aspects (Specification_Node)
and then Prev_Ids (Specification_Node)
then
-- Loop through each previous id
declare
Prev_Id : Node_Id := Prev (Specification_Node);
begin
loop
Set_Aspect_Specifications
(Prev_Id, Aspect_Specifications (Specification_Node));
-- Exit when we reach the first parameter in the list
exit when not Prev_Ids (Prev_Id);
Prev_Id := Prev (Prev_Id);
end loop;
end;
end if;
if Token = Tok_Right_Paren then
Scan; -- past right paren
exit Specification_Loop;
elsif Token = Tok_Semicolon then
Save_Scan_State (Scan_State);
Scan; -- past semicolon
end if;
-- Special check for common error of using comma instead of semicolon
elsif Token = Tok_Comma then
T_Semicolon;
-- Special check for omitted separator
elsif Token = Tok_Identifier then
T_Semicolon;
-- If nothing sensible, skip to next semicolon or right paren
else
T_Semicolon;
Resync_Semicolon_List;
if Token = Tok_Semicolon then
Scan; -- past semicolon
else
T_Right_Paren;
exit Specification_Loop;
end if;
end if;
end loop Specification_Loop;
return Specification_List;
end P_Formal_Part;
----------------------------------
-- 6.1 Parameter Specification --
----------------------------------
-- Parsed by P_Formal_Part (6.1)
---------------
-- 6.1 Mode --
---------------
-- MODE ::= [in] | in out | out
-- There is no explicit node in the tree for the Mode. Instead the
-- In_Present and Out_Present flags are set in the parent node to
-- record the presence of keywords specifying the mode.
-- Error_Recovery: cannot raise Error_Resync
procedure P_Mode (Node : Node_Id) is
begin
if Token = Tok_In then
Scan; -- past IN
Set_In_Present (Node, True);
if Style.Mode_In_Check and then Token /= Tok_Out then
Error_Msg_SP -- CODEFIX
("(style) IN should be omitted");
end if;
-- Since Ada 2005, formal objects can have an anonymous access type,
-- and of course carry a mode indicator.
if Token = Tok_Access
and then Nkind (Node) /= N_Formal_Object_Declaration
then
Error_Msg_SP ("IN not allowed together with ACCESS");
Scan; -- past ACCESS
end if;
end if;
if Token = Tok_Out then
Scan; -- past OUT
Set_Out_Present (Node, True);
end if;
if Token = Tok_In then
Error_Msg_SC ("IN must precede OUT in parameter mode");
Scan; -- past IN
Set_In_Present (Node, True);
end if;
end P_Mode;
--------------------------
-- 6.3 Subprogram Body --
--------------------------
-- Parsed by P_Subprogram (6.1)
-----------------------------------
-- 6.4 Procedure Call Statement --
-----------------------------------
-- Parsed by P_Sequence_Of_Statements (5.1)
------------------------
-- 6.4 Function Call --
------------------------
-- Parsed by P_Name (4.1)
--------------------------------
-- 6.4 Actual Parameter Part --
--------------------------------
-- Parsed by P_Name (4.1)
--------------------------------
-- 6.4 Parameter Association --
--------------------------------
-- Parsed by P_Name (4.1)
------------------------------------
-- 6.4 Explicit Actual Parameter --
------------------------------------
-- Parsed by P_Name (4.1)
---------------------------
-- 6.5 Return Statement --
---------------------------
-- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
--
-- EXTENDED_RETURN_STATEMENT ::=
-- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
-- [:= EXPRESSION]
-- [ASPECT_SPECIFICATION] [do
-- HANDLED_SEQUENCE_OF_STATEMENTS
-- end return];
--
-- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
-- RETURN_STATEMENT ::= return [EXPRESSION];
-- Error recovery: can raise Error_Resync
procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
-- Note: We don't need to check Ada_Version here, because this is
-- only called in >= Ada 2005 cases anyway.
Not_Null_Present : constant Boolean := P_Null_Exclusion;
begin
Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
if Token = Tok_Access then
Set_Object_Definition
(Decl_Node, P_Access_Definition (Not_Null_Present));
else
Set_Object_Definition
(Decl_Node, P_Subtype_Indication (Not_Null_Present));
end if;
end P_Return_Subtype_Indication;
-- Error recovery: can raise Error_Resync
function P_Return_Object_Declaration return Node_Id is
Return_Obj : Node_Id;
Decl_Node : Node_Id;
begin
Return_Obj := Token_Node;
Change_Identifier_To_Defining_Identifier (Return_Obj);
Warn_If_Standard_Redefinition (Return_Obj);
Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
Set_Defining_Identifier (Decl_Node, Return_Obj);
Scan; -- past identifier
Scan; -- past :
-- First an error check, if we have two identifiers in a row, a likely
-- possibility is that the first of the identifiers is an incorrectly
-- spelled keyword. See similar check in P_Identifier_Declarations.
if Token = Tok_Identifier then
declare
SS : Saved_Scan_State;
I2 : Boolean;
begin
Save_Scan_State (SS);
Scan; -- past initial identifier
I2 := (Token = Tok_Identifier);
Restore_Scan_State (SS);
if I2
and then
(Bad_Spelling_Of (Tok_Access) or else
Bad_Spelling_Of (Tok_Aliased) or else
Bad_Spelling_Of (Tok_Constant))
then
null;
end if;
end;
end if;
-- We allow "constant" here (as in "return Result : constant
-- T..."). This is not in the latest RM, but the ARG is considering an
-- AI on the subject (see AI05-0015-1), which we expect to be approved.
if Token = Tok_Constant then
Scan; -- past CONSTANT
Set_Constant_Present (Decl_Node);
if Token = Tok_Aliased then
Error_Msg_SC -- CODEFIX
("ALIASED should be before CONSTANT");
Scan; -- past ALIASED
Set_Aliased_Present (Decl_Node);
end if;
elsif Token = Tok_Aliased then
Scan; -- past ALIASED
Set_Aliased_Present (Decl_Node);
-- The restrictions on the use of aliased in an extended return
-- are semantic, not syntactic.
if Token = Tok_Constant then
Scan; -- past CONSTANT
Set_Constant_Present (Decl_Node);
end if;
end if;
P_Return_Subtype_Indication (Decl_Node);
if Token = Tok_Colon_Equal then
Scan; -- past :=
Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
Set_Has_Init_Expression (Decl_Node);
end if;
return Decl_Node;
end P_Return_Object_Declaration;
-- Error recovery: can raise Error_Resync
function P_Return_Statement return Node_Id is
-- The caller has checked that the initial token is RETURN
function Is_Extended return Boolean;
-- Scan state is just after RETURN (and is left that way). Determine
-- whether this is a simple or extended return statement by looking
-- ahead for "identifier :", which implies extended.
-----------------
-- Is_Extended --
-----------------
function Is_Extended return Boolean is
Scan_State : Saved_Scan_State;
Is_Extended : Boolean := False;
begin
if Token = Tok_Identifier then
Save_Scan_State (Scan_State); -- at identifier
Scan; -- past identifier
if Token = Tok_Colon then
Is_Extended := True;
end if;
Restore_Scan_State (Scan_State); -- to identifier
end if;
return Is_Extended;
end Is_Extended;
Ret_Sloc : constant Source_Ptr := Token_Ptr;
Ret_Strt : constant Column_Number := Start_Column;
Ret_Node : Node_Id;
Decl : Node_Id;
-- Start of processing for P_Return_Statement
begin
Scan; -- past RETURN
-- Simple_return_statement, no expression, return an
-- N_Simple_Return_Statement node with the expression field left Empty.
if Token = Tok_Semicolon then
Scan; -- past ;
Ret_Node := New_Node (N_Simple_Return_Statement, Ret_Sloc);
-- Nontrivial case
else
-- Extended_return_statement (Ada 2005 only -- AI-318):
if Is_Extended then
Error_Msg_Ada_2005_Extension ("extended return statement");
Ret_Node := New_Node (N_Extended_Return_Statement, Ret_Sloc);
Decl := P_Return_Object_Declaration;
Set_Return_Object_Declarations (Ret_Node, New_List (Decl));
if Token = Tok_With then
P_Aspect_Specifications (Decl, False);
end if;
if Token = Tok_Do then
Push_Scope_Stack;
Scopes (Scope.Last).Ecol := Ret_Strt;
Scopes (Scope.Last).Etyp := E_Return;
Scopes (Scope.Last).Labl := Error;
Scopes (Scope.Last).Sloc := Ret_Sloc;
Scan; -- past DO
Set_Handled_Statement_Sequence
(Ret_Node, P_Handled_Sequence_Of_Statements);
End_Statements;
-- Do we need to handle Error_Resync here???
end if;
-- Simple_return_statement or Return_when_Statement
-- with expression.
-- We avoid trying to scan an expression if we are at an
-- expression terminator since in that case the best error
-- message is probably that we have a missing semicolon.
else
Ret_Node := New_Node (N_Simple_Return_Statement, Ret_Sloc);
if Token not in Token_Class_Eterm then
Set_Expression (Ret_Node, P_Expression_No_Right_Paren);
end if;
-- When the next token is WHEN or IF we know that we are looking
-- at a Return_when_statement
if Token = Tok_When and then not Missing_Semicolon_On_When then
Error_Msg_GNAT_Extension ("return when statement", Token_Ptr);
Mutate_Nkind (Ret_Node, N_Return_When_Statement);
Scan; -- past WHEN
Set_Condition (Ret_Node, P_Condition);
-- Allow IF instead of WHEN, giving error message
elsif Token = Tok_If then
Error_Msg_GNAT_Extension ("return when statement", Token_Ptr);
Mutate_Nkind (Ret_Node, N_Return_When_Statement);
T_When;
Scan; -- past IF used in place of WHEN
Set_Condition (Ret_Node, P_Condition);
end if;
end if;
TF_Semicolon;
end if;
return Ret_Node;
end P_Return_Statement;
end Ch6;