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-------------------------------------------------------------------------------
--
-- Copyright (C) 2009 Stephe Leake
-- Copyright (C) 1999 Ted Dennison
--
-- This file is part of the OpenToken package.
--
-- The OpenToken package is free software; you can redistribute it and/or
-- modify it under the terms of the GNU General Public License as published
-- by the Free Software Foundation; either version 3, or (at your option)
-- any later version. The OpenToken package is distributed in the hope that
-- it will be useful, but WITHOUT ANY WARRANTY; without even the implied
-- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details. You should have received
-- a copy of the GNU General Public License distributed with the OpenToken
-- package; see file GPL.txt. If not, write to the Free Software Foundation,
-- 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
--
-- As a special exception, if other files instantiate generics from
-- this unit, or you link this unit with other files to produce an
-- executable, this unit does not by itself cause the resulting
-- executable to be covered by the GNU General Public License. This
-- exception does not however invalidate any other reasons why the
-- executable file might be covered by the GNU Public License.
--
-------------------------------------------------------------------------------
with Ada.Tags;
with Ada.Text_IO;
package body OpenToken.Token.Enumerated is
function Get
(ID : in Token_ID := Token_ID'First;
Name : in String := "";
Build : in Action := null)
return Instance'Class
is begin
if Name = "" then
return Instance'Class (Instance'(Name => null, ID => ID, Build => Build));
else
return Instance'Class (Instance'(Name => new String'(Name), ID => ID, Build => Build));
end if;
end Get;
procedure Set_Build (Token : in out Instance'Class; Build : in Action)
is begin
Token.Build := Build;
end Set_Build;
function ID (Token : in Instance'Class) return Token_ID is
begin
return Token.ID;
end ID;
procedure Set_ID
(Token : in out Instance'Class;
ID : in Token_ID)
is begin
Token.ID := ID;
end Set_ID;
overriding procedure Parse
(Match : access Instance;
Analyzer : in out Source_Class;
Actively : in Boolean := True)
is
use type Ada.Tags.Tag;
Next_Token : constant OpenToken.Token.Class := Get (Analyzer);
begin
if Trace_Parse then
Trace_Indent := Trace_Indent + 1;
if Actively then
Trace_Put ("parsing");
else
Trace_Put ("trying");
end if;
Ada.Text_IO.Put_Line (" enumerated " & Name_Dispatch (Match));
end if;
if Instance (Next_Token).ID = Match.ID then
-- Next_Token was passed to a dispatching Create by
-- Find_Next; copy the results of that.
--
-- Previous versions of OpenToken called Create again here,
-- with an argument of Lexeme (Analyzer), which is wrong
-- when Next_Token was read from the lookahead queue, since
-- the Lexeme reads from the input buffer, which is not
-- preserved in the lookahead queue. We added Copy to handle
-- that; lexeme is preserved in the copy of the token in the
-- lookahead queue.
--
-- Note that we can't just use ':='; that doesn't dispatch,
-- so it only copies the ID, which is pointless.
--
-- This change (not calling Create here) will cause user
-- applications to silently fail (silently meaning the
-- compiler won't catch it; user unit tests should catch the
-- problem). We can't make Copy abstract, because
-- Enumerated.Instance can't be abstract.
if Actively then
if Next_Token'Tag = Class (Match.all)'Tag then
Copy (To => Class (Match.all), From => Next_Token);
if Match.Build /= null then
Match.Build (Match.all);
end if;
else
-- It is the parser programmer's job to ensure these types match.
raise Programmer_Error with
"Expected a token of type " & Ada.Tags.Expanded_Name (Class (Match.all)'Tag) &
"'Class but found a " & Ada.Tags.Expanded_Name (Next_Token'Tag);
end if;
end if;
else
if Actively then
raise Parse_Error with "Expected " & Name_Dispatch (Match) & " but found " & Name_Dispatch (Next_Token);
else
-- The spec says "raise Parse_Error with no message". If
-- we leave out 'with ""' here, GNAT attaches a message
-- giving the line number. That's useful in general, but
-- fails our unit test. And it would be painful (and
-- non-portable) to maintain a unit test that checked for
-- the GNAT string, since it has line numbers in it. So
-- we override it in this case.
--
-- The point of "raise with no message" is to not spend
-- time computing a nice user message, because it will be
-- thrown away. I'm not clear whether 'with ""' or the
-- GNAT default is faster, but it probably doesn't matter
-- much.
raise Parse_Error with "";
end if;
end if;
Find_Next (Analyzer, Look_Ahead => not Actively);
if Trace_Parse then
Trace_Put ("...succeeded"); Ada.Text_IO.New_Line;
Trace_Indent := Trace_Indent - 1;
end if;
exception
when others =>
if Trace_Parse then
Trace_Put ("...failed"); Ada.Text_IO.New_Line;
Trace_Indent := Trace_Indent - 1;
end if;
raise;
end Parse;
overriding function Name (Token : in Instance) return String
is begin
if Token.Name = null then
return Token_ID'Image (Token.ID);
else
return Token.Name.all;
end if;
end Name;
end OpenToken.Token.Enumerated;
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