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gcc/gcc/ada/par-util.adb
Ed Schonberg 3c08de3407 [Ada] Prototype implementastion of Ada2020 Map-reduce construct 
2019-12-16  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* scng.adb (Scan): In Ada2020, a left-bracket indicates the
	start of an homogenous aggregate.
	* par-ch4.adb (P_Reduction_Attribute_Reference): New procedure.
	(P_Aggregate): Recognize Ada2020 bracket-delimited aggregates.
	(P_Primary): Ditto.
	* par-util.adb (Comma_Present): Return false on a right bracket
	in Ada2020, indicating the end of an aggregate.
	* snames.ads-tmpl: Introduce Name_Reduce and Attribute Reduce.
	* sinfo.ads, sinfo.adb (Is_Homogeneous_Aggregate): New flag on
	aggregates, to designate an Ada2020 array or container aggregate
	that is bracket-delimited in the source.
	* sem_attr.adb (Analyze_Attribute): For attribute Reduce, verify
	that two arguments are present, and verify that the prefix is a
	stream or an object that is iterable (array or contrainer).
	(Resolve_Attribute): For attribute Reduce, resolve initial value
	with the type of the context. Type-checking of element type of
	prefix is performed after expansion.
	* exp_attr.adb (Expand_N_Attribute_Reference): For attribute
	Reduce, expand into a loop: a) If prefix is an aggregate with a
	single iterated component association, use its iterator
	specification to construct a loop, b) If prefix is a name, build
	a loop using an element iterator loop.
	* scans.ads: Add brackets tokens.

From-SVN: r279431
2019-12-16 10:34:37 +00:00

797 lines
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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- P A R . U T I L --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2019, 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 Csets; use Csets;
with Namet.Sp; use Namet.Sp;
with Stylesw; use Stylesw;
with Uintp; use Uintp;
with Warnsw; use Warnsw;
with GNAT.Spelling_Checker; use GNAT.Spelling_Checker;
separate (Par)
package body Util is
---------------------
-- Bad_Spelling_Of --
---------------------
function Bad_Spelling_Of (T : Token_Type) return Boolean is
Tname : constant String := Token_Type'Image (T);
-- Characters of token name
S : String (1 .. Tname'Last - 4);
-- Characters of token name folded to lower case, omitting TOK_ at start
M1 : String (1 .. 42) := "incorrect spelling of keyword ************";
M2 : String (1 .. 44) := "illegal abbreviation of keyword ************";
-- Buffers used to construct error message
P1 : constant := 30;
P2 : constant := 32;
-- Starting subscripts in M1, M2 for keyword name
SL : constant Natural := S'Length;
-- Length of expected token name excluding TOK_ at start
begin
if Token /= Tok_Identifier then
return False;
end if;
for J in S'Range loop
S (J) := Fold_Lower (Tname (J + 4));
end loop;
Get_Name_String (Token_Name);
-- A special check for case of PROGRAM used for PROCEDURE
if T = Tok_Procedure
and then Name_Len = 7
and then Name_Buffer (1 .. 7) = "program"
then
Error_Msg_SC -- CODEFIX
("PROCEDURE expected");
Token := T;
return True;
-- A special check for an illegal abbreviation
elsif Name_Len < S'Length
and then Name_Len >= 4
and then Name_Buffer (1 .. Name_Len) = S (1 .. Name_Len)
then
for J in 1 .. S'Last loop
M2 (P2 + J - 1) := Fold_Upper (S (J));
end loop;
Error_Msg_SC (M2 (1 .. P2 - 1 + S'Last));
Token := T;
return True;
end if;
-- Now we go into the full circuit to check for a misspelling
-- Never consider something a misspelling if either the actual or
-- expected string is less than 3 characters (before this check we
-- used to consider i to be a misspelled if in some cases).
if SL < 3 or else Name_Len < 3 then
return False;
-- Special case: prefix matches, i.e. the leading characters of the
-- token that we have exactly match the required keyword. If there
-- are at least two characters left over, assume that we have a case
-- of two keywords joined together which should not be joined.
elsif Name_Len > SL + 1
and then S = Name_Buffer (1 .. SL)
then
Scan_Ptr := Token_Ptr + S'Length;
Error_Msg_S ("|missing space");
Token := T;
return True;
end if;
if Is_Bad_Spelling_Of (Name_Buffer (1 .. Name_Len), S) then
for J in 1 .. S'Last loop
M1 (P1 + J - 1) := Fold_Upper (S (J));
end loop;
Error_Msg_SC -- CODFIX
(M1 (1 .. P1 - 1 + S'Last));
Token := T;
return True;
else
return False;
end if;
end Bad_Spelling_Of;
----------------------
-- Check_95_Keyword --
----------------------
-- On entry, the caller has checked that current token is an identifier
-- whose name matches the name of the 95 keyword New_Tok.
procedure Check_95_Keyword (Token_95, Next : Token_Type) is
Scan_State : Saved_Scan_State;
begin
Save_Scan_State (Scan_State); -- at identifier/keyword
Scan; -- past identifier/keyword
if Token = Next then
Restore_Scan_State (Scan_State); -- to identifier
Error_Msg_Name_1 := Token_Name;
Error_Msg_SC ("(Ada 83) keyword* cannot be used!");
Token := Token_95;
else
Restore_Scan_State (Scan_State); -- to identifier
end if;
end Check_95_Keyword;
----------------------
-- Check_Bad_Layout --
----------------------
procedure Check_Bad_Layout is
begin
if RM_Column_Check and then Token_Is_At_Start_Of_Line
and then Start_Column <= Scopes (Scope.Last).Ecol
then
Error_Msg_BC -- CODEFIX
("(style) incorrect layout");
end if;
end Check_Bad_Layout;
--------------------------
-- Check_Future_Keyword --
--------------------------
procedure Check_Future_Keyword is
begin
-- Ada 2005 (AI-284): Compiling in Ada 95 mode we warn that INTERFACE,
-- OVERRIDING, and SYNCHRONIZED are new reserved words.
if Ada_Version = Ada_95
and then Warn_On_Ada_2005_Compatibility
then
if Nam_In (Token_Name, Name_Overriding, Name_Synchronized)
or else (Token_Name = Name_Interface
and then Prev_Token /= Tok_Pragma)
then
Error_Msg_N ("& is a reserved word in Ada 2005?y?", Token_Node);
end if;
end if;
-- Similarly, warn about Ada 2012 reserved words
if Ada_Version in Ada_95 .. Ada_2005
and then Warn_On_Ada_2012_Compatibility
then
if Token_Name = Name_Some then
Error_Msg_N ("& is a reserved word in Ada 2012?y?", Token_Node);
end if;
end if;
-- Note: we deliberately do not emit these warnings when operating in
-- Ada 83 mode because in that case we assume the user is building
-- legacy code anyway and is not interested in updating Ada versions.
end Check_Future_Keyword;
--------------------------
-- Check_Misspelling_Of --
--------------------------
procedure Check_Misspelling_Of (T : Token_Type) is
begin
if Bad_Spelling_Of (T) then
null;
end if;
end Check_Misspelling_Of;
-----------------------------
-- Check_Simple_Expression --
-----------------------------
procedure Check_Simple_Expression (E : Node_Id) is
begin
if Expr_Form = EF_Non_Simple then
Error_Msg_N ("this expression must be parenthesized", E);
end if;
end Check_Simple_Expression;
---------------------------------------
-- Check_Simple_Expression_In_Ada_83 --
---------------------------------------
procedure Check_Simple_Expression_In_Ada_83 (E : Node_Id) is
begin
if Expr_Form = EF_Non_Simple then
if Ada_Version = Ada_83 then
Error_Msg_N ("(Ada 83) this expression must be parenthesized!", E);
end if;
end if;
end Check_Simple_Expression_In_Ada_83;
------------------------
-- Check_Subtype_Mark --
------------------------
function Check_Subtype_Mark (Mark : Node_Id) return Node_Id is
begin
if Nkind (Mark) = N_Identifier
or else Nkind (Mark) = N_Selected_Component
or else (Nkind (Mark) = N_Attribute_Reference
and then Is_Type_Attribute_Name (Attribute_Name (Mark)))
or else Mark = Error
then
return Mark;
else
Error_Msg ("subtype mark expected", Sloc (Mark));
return Error;
end if;
end Check_Subtype_Mark;
-------------------
-- Comma_Present --
-------------------
function Comma_Present return Boolean is
Scan_State : Saved_Scan_State;
Paren_Count : Nat;
begin
-- First check, if a comma is present, then a comma is present
if Token = Tok_Comma then
T_Comma;
return True;
-- If we have a right paren, then that is taken as ending the list
-- i.e. no comma is present.
-- Ditto for a right bracket in Ada2020.
elsif Token = Tok_Right_Paren
or else (Token = Tok_Right_Bracket and then Ada_Version >= Ada_2020)
then
return False;
-- If pragmas, then get rid of them and make a recursive call
-- to process what follows these pragmas.
elsif Token = Tok_Pragma then
P_Pragmas_Misplaced;
return Comma_Present;
-- At this stage we have an error, and the goal is to decide on whether
-- or not we should diagnose an error and report a (non-existent)
-- comma as being present, or simply to report no comma is present
-- If we are a semicolon, then the question is whether we have a missing
-- right paren, or whether the semicolon should have been a comma. To
-- guess the right answer, we scan ahead keeping track of the paren
-- level, looking for a clue that helps us make the right decision.
-- This approach is highly accurate in the single error case, and does
-- not make bad mistakes in the multiple error case (indeed we can't
-- really make a very bad decision at this point in any case).
elsif Token = Tok_Semicolon then
Save_Scan_State (Scan_State);
Scan; -- past semicolon
-- Check for being followed by identifier => which almost certainly
-- means we are still in a parameter list and the comma should have
-- been a semicolon (such a sequence could not follow a semicolon)
if Token = Tok_Identifier then
Scan;
if Token = Tok_Arrow then
goto Assume_Comma;
end if;
end if;
-- If that test didn't work, loop ahead looking for a comma or
-- semicolon at the same parenthesis level. Always remember that
-- we can't go badly wrong in an error situation like this.
Paren_Count := 0;
-- Here is the look ahead loop, Paren_Count tells us whether the
-- token we are looking at is at the same paren level as the
-- suspicious semicolon that we are trying to figure out.
loop
-- If we hit another semicolon or an end of file, and we have
-- not seen a right paren or another comma on the way, then
-- probably the semicolon did end the list. Indeed that is
-- certainly the only single error correction possible here.
if Token = Tok_Semicolon or else Token = Tok_EOF then
Restore_Scan_State (Scan_State);
return False;
-- A comma at the same paren level as the semicolon is a strong
-- indicator that the semicolon should have been a comma, indeed
-- again this is the only possible single error correction.
elsif Token = Tok_Comma then
exit when Paren_Count = 0;
-- A left paren just bumps the paren count
elsif Token = Tok_Left_Paren then
Paren_Count := Paren_Count + 1;
-- A right paren that is at the same paren level as the semicolon
-- also means that the only possible single error correction is
-- to assume that the semicolon should have been a comma. If we
-- are not at the same paren level, then adjust the paren level.
elsif Token = Tok_Right_Paren then
exit when Paren_Count = 0;
Paren_Count := Paren_Count - 1;
end if;
-- Keep going, we haven't made a decision yet
Scan;
end loop;
-- If we fall through the loop, it means that we found a terminating
-- right paren or another comma. In either case it is reasonable to
-- assume that the semicolon was really intended to be a comma. Also
-- come here for the identifier arrow case.
<<Assume_Comma>>
Restore_Scan_State (Scan_State);
Error_Msg_SC -- CODEFIX
("|"";"" should be "",""");
Scan; -- past the semicolon
return True;
-- If we are not at semicolon or a right paren, then we base the
-- decision on whether or not the next token can be part of an
-- expression. If not, then decide that no comma is present (the
-- caller will eventually generate a missing right parent message)
elsif Token in Token_Class_Eterm then
return False;
-- Otherwise we assume a comma is present, even if none is present,
-- since the next token must be part of an expression, so if we were
-- at the end of the list, then there is more than one error present.
else
T_Comma; -- to give error
return True;
end if;
end Comma_Present;
-----------------------
-- Discard_Junk_List --
-----------------------
procedure Discard_Junk_List (L : List_Id) is
pragma Warnings (Off, L);
begin
null;
end Discard_Junk_List;
-----------------------
-- Discard_Junk_Node --
-----------------------
procedure Discard_Junk_Node (N : Node_Id) is
pragma Warnings (Off, N);
begin
null;
end Discard_Junk_Node;
------------
-- Ignore --
------------
procedure Ignore (T : Token_Type) is
begin
while Token = T loop
if T = Tok_Comma then
Error_Msg_SC -- CODEFIX
("|extra "","" ignored");
elsif T = Tok_Left_Paren then
Error_Msg_SC -- CODEFIX
("|extra ""("" ignored");
-- Note: the following error used to be labeled as a non-serious
-- error like the other similar messages here (with a | at the start
-- of the message). But this caused some annoying cascaded errors
-- that were confusing, as shown by this example:
-- A : array (1 .. 9) of Integer :=
-- ((1 .. 2) => 0,
-- 1 2 3
-- >>> positional aggregate cannot have one component
-- >>> named association cannot follow positional association
-- >>> extra ")" ignored
-- So we decided to label it as serious after all
elsif T = Tok_Right_Paren then
Error_Msg_SC -- CODEFIX
("extra "")"" ignored");
elsif T = Tok_Semicolon then
Error_Msg_SC -- CODEFIX
("|extra "";"" ignored");
elsif T = Tok_Colon then
Error_Msg_SC -- CODEFIX
("|extra "":"" ignored");
else
declare
Tname : constant String := Token_Type'Image (Token);
begin
Error_Msg_SC ("|extra " & Tname (5 .. Tname'Last) & "ignored");
end;
end if;
Scan; -- Scan past ignored token
end loop;
end Ignore;
----------------------------
-- Is_Reserved_Identifier --
----------------------------
function Is_Reserved_Identifier (C : Id_Check := None) return Boolean is
begin
if not Is_Reserved_Keyword (Token) then
return False;
else
declare
Ident_Casing : constant Casing_Type :=
Identifier_Casing (Current_Source_File);
Key_Casing : constant Casing_Type :=
Keyword_Casing (Current_Source_File);
begin
-- If the casing of identifiers and keywords is different in
-- this source file, and the casing of this token matches the
-- keyword casing, then we return False, since it is pretty
-- clearly intended to be a keyword.
if Ident_Casing = Unknown
or else Key_Casing = Unknown
or else Ident_Casing = Key_Casing
or else Determine_Token_Casing /= Key_Casing
then
return True;
-- Here we have a keyword written clearly with keyword casing.
-- In default mode, we would not be willing to consider this as
-- a reserved identifier, but if C is set, we may still accept it
elsif C /= None then
declare
Scan_State : Saved_Scan_State;
OK_Next_Tok : Boolean;
begin
Save_Scan_State (Scan_State);
Scan;
if Token_Is_At_Start_Of_Line then
return False;
end if;
case C is
when None =>
raise Program_Error;
when C_Comma_Right_Paren =>
OK_Next_Tok :=
Token = Tok_Comma or else Token = Tok_Right_Paren;
when C_Comma_Colon =>
OK_Next_Tok :=
Token = Tok_Comma or else Token = Tok_Colon;
when C_Do =>
OK_Next_Tok :=
Token = Tok_Do;
when C_Dot =>
OK_Next_Tok :=
Token = Tok_Dot;
when C_Greater_Greater =>
OK_Next_Tok :=
Token = Tok_Greater_Greater;
when C_In =>
OK_Next_Tok :=
Token = Tok_In;
when C_Is =>
OK_Next_Tok :=
Token = Tok_Is;
when C_Left_Paren_Semicolon =>
OK_Next_Tok :=
Token = Tok_Left_Paren or else Token = Tok_Semicolon;
when C_Use =>
OK_Next_Tok :=
Token = Tok_Use;
when C_Vertical_Bar_Arrow =>
OK_Next_Tok :=
Token = Tok_Vertical_Bar or else Token = Tok_Arrow;
end case;
Restore_Scan_State (Scan_State);
if OK_Next_Tok then
return True;
end if;
end;
end if;
end;
end if;
-- If we fall through it is not a reserved identifier
return False;
end Is_Reserved_Identifier;
----------------------
-- Merge_Identifier --
----------------------
procedure Merge_Identifier (Prev : Node_Id; Nxt : Token_Type) is
begin
if Token /= Tok_Identifier then
return;
end if;
declare
S : Saved_Scan_State;
T : Token_Type;
begin
Save_Scan_State (S);
Scan;
T := Token;
Restore_Scan_State (S);
if T /= Nxt then
return;
end if;
end;
-- Check exactly one space between identifiers
if Source (Token_Ptr - 1) /= ' '
or else Int (Token_Ptr) /=
Int (Prev_Token_Ptr) + Length_Of_Name (Chars (Prev)) + 1
then
return;
end if;
-- Do the merge
Get_Name_String (Chars (Token_Node));
declare
Buf : constant String (1 .. Name_Len) :=
Name_Buffer (1 .. Name_Len);
begin
Get_Name_String (Chars (Prev));
Add_Char_To_Name_Buffer ('_');
Add_Str_To_Name_Buffer (Buf);
Set_Chars (Prev, Name_Find);
end;
Error_Msg_Node_1 := Prev;
Error_Msg_SC ("unexpected identifier, possibly & was meant here");
Scan;
end Merge_Identifier;
-------------------
-- Next_Token_Is --
-------------------
function Next_Token_Is (Tok : Token_Type) return Boolean is
Scan_State : Saved_Scan_State;
Result : Boolean;
begin
Save_Scan_State (Scan_State);
Scan;
Result := (Token = Tok);
Restore_Scan_State (Scan_State);
return Result;
end Next_Token_Is;
-------------------
-- No_Constraint --
-------------------
procedure No_Constraint is
begin
-- If we have a token that could start a constraint on the same line
-- then cnsider this an illegal constraint. It seems unlikely it could
-- be anything else if it is on the same line.
if Token in Token_Class_Consk then
Error_Msg_SC ("constraint not allowed here");
Discard_Junk_Node (P_Constraint_Opt);
end if;
end No_Constraint;
---------------------
-- Pop_Scope_Stack --
---------------------
procedure Pop_Scope_Stack is
begin
pragma Assert (Scope.Last > 0);
Scope.Decrement_Last;
if Include_Subprogram_In_Messages
and then Scopes (Scope.Last).Labl /= Error
then
Current_Node := Scopes (Scope.Last).Labl;
end if;
if Debug_Flag_P then
Error_Msg_Uint_1 := UI_From_Int (Scope.Last);
Error_Msg_SC ("decrement scope stack ptr, new value = ^!");
end if;
end Pop_Scope_Stack;
----------------------
-- Push_Scope_Stack --
----------------------
procedure Push_Scope_Stack is
begin
Scope.Increment_Last;
if Style_Check_Max_Nesting_Level
and then Scope.Last = Style_Max_Nesting_Level + 1
then
Error_Msg
("(style) maximum nesting level exceeded",
First_Non_Blank_Location);
end if;
Scopes (Scope.Last).Junk := False;
Scopes (Scope.Last).Node := Empty;
if Debug_Flag_P then
Error_Msg_Uint_1 := UI_From_Int (Scope.Last);
Error_Msg_SC ("increment scope stack ptr, new value = ^!");
end if;
end Push_Scope_Stack;
----------------------
-- Separate_Present --
----------------------
function Separate_Present return Boolean is
Scan_State : Saved_Scan_State;
begin
if Token = Tok_Separate then
return True;
elsif Token /= Tok_Identifier then
return False;
else
Save_Scan_State (Scan_State);
Scan; -- past identifier
if Token = Tok_Semicolon then
Restore_Scan_State (Scan_State);
return Bad_Spelling_Of (Tok_Separate);
else
Restore_Scan_State (Scan_State);
return False;
end if;
end if;
end Separate_Present;
--------------------------
-- Signal_Bad_Attribute --
--------------------------
procedure Signal_Bad_Attribute is
begin
Bad_Attribute (Token_Node, Token_Name, Warn => False);
end Signal_Bad_Attribute;
-----------------------------
-- Token_Is_At_End_Of_Line --
-----------------------------
function Token_Is_At_End_Of_Line return Boolean is
S : Source_Ptr;
begin
-- Skip past blanks and horizontal tabs
S := Scan_Ptr;
while Source (S) = ' ' or else Source (S) = ASCII.HT loop
S := S + 1;
end loop;
-- We are at end of line if at a control character (CR/LF/VT/FF/EOF)
-- or if we are at the start of an end of line comment sequence.
return Source (S) < ' '
or else (Source (S) = '-' and then Source (S + 1) = '-');
end Token_Is_At_End_Of_Line;
-------------------------------
-- Token_Is_At_Start_Of_Line --
-------------------------------
function Token_Is_At_Start_Of_Line return Boolean is
begin
return (Token_Ptr = First_Non_Blank_Location or else Token = Tok_EOF);
end Token_Is_At_Start_Of_Line;
-----------------------------------
-- Warn_If_Standard_Redefinition --
-----------------------------------
procedure Warn_If_Standard_Redefinition (N : Node_Id) is
begin
if Warn_On_Standard_Redefinition then
declare
C : constant Entity_Id := Current_Entity (N);
begin
if Present (C) and then Sloc (C) = Standard_Location then
Error_Msg_N ("redefinition of entity& in Standard?K?", N);
end if;
end;
end if;
end Warn_If_Standard_Redefinition;
end Util;
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