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-------------------------------------------------------------------------------
--
-- 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 2, 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.
--
-- Maintainer: Ted Dennison (dennison@telepath.com)
--
-- Update History:
-- $Log: simple_integer_token.adb,v $
-- Revision 1.1 2000/01/27 21:05:01 Ted
-- An implementation of a simple nonterminal interger token.
--
--
--
-------------------------------------------------------------------------------
with Ada.Exceptions;
-------------------------------------------------------------------------------
-- This package declares a type for designating an integer literal.
-------------------------------------------------------------------------------
package body Simple_Integer_Token is
----------------------------------------------------------------------------
-- Get a nonterminal token with the given ID.
----------------------------------------------------------------------------
function Get (ID : in Token.Token_ID;
Value : in Integer := 0) return Instance'Class is
begin
return Instance'Class(Instance'(Nonterminal.Instance(Nonterminal.Get(ID)) with Value => Value));
end Get;
----------------------------------------------------------------------------
-- Return the value of the given integer token.
----------------------------------------------------------------------------
function Value (Subject : in Instance) return Integer is
begin
return Subject.Value;
end Value;
----------------------------------------------------------------------------
-- Create a token by simply up-converting the given token, and
-- changing its ID to match the given ID.
----------------------------------------------------------------------------
procedure Synthesize_By_Copying (New_Token : out Instance;
Source : in Token.Instance'Class;
To_ID : in Token.Token_ID) is
begin
if Source in Integer_Literal.Class then
New_Token := (Nonterminal.Instance(Nonterminal.Get(To_ID)) with
Value => Integer_Literal.Value(Integer_Literal.Class(Source)));
elsif Source in Class then
New_Token := (Nonterminal.Instance(Nonterminal.Get(To_ID)) with
Value => Instance(Source).Value);
else
Ada.Exceptions.Raise_Exception
(Nonterminal.Invalid_Synth_Argument'Identity,
"Token " & Token.Token_ID'Image(To_ID) & " cannot be synthesized " &
"solely from a " & Token.Token_ID'Image(Token.ID(Source)) & "."
);
end if;
end Synthesize_By_Copying;
procedure Synthesize_Add (New_Token : out Nonterminal.Class;
Source : in Token_List.Instance'Class;
To_ID : in Token.Token_ID) is
Left : Token_List.List_Iterator := Token_List.Initial_Iterator(Source);
Right : Token_List.List_Iterator := Token_List.Initial_Iterator(Source);
begin
-- Move "Right" over to the third item;
Token_List.Next_Token (Right);
Token_List.Next_Token (Right);
New_Token := Class(Instance'(Token.Instance(Token.Get (To_ID)) with
(Value (Class (Token_List.Token_Handle(Left).all)) +
Value (Class (Token_List.Token_Handle(Right).all))
)
)
);
exception
when Constraint_Error =>
Ada.Exceptions.Raise_Exception
(Nonterminal.Invalid_Synth_Argument'Identity,
"Token " & Token.Token_ID'Image(To_ID) & " cannot be synthesized " &
"from a " &
Token.Token_ID'Image (Token.ID (Token_List.Token_Handle(Left).all) ) &
" and a " &
Token.Token_ID'Image (Token.ID (Token_List.Token_Handle(Right).all) ) &
"."
);
end Synthesize_Add;
procedure Synthesize_Multiply (New_Token : out Nonterminal.Class;
Source : in Token_List.Instance'Class;
To_ID : in Token.Token_ID) is
Left : Token_List.List_Iterator := Token_List.Initial_Iterator(Source);
Right : Token_List.List_Iterator := Token_List.Initial_Iterator(Source);
begin
-- Move "Right" over to the third item;
Token_List.Next_Token (Right);
Token_List.Next_Token (Right);
New_Token := Class(Instance'
(Token.Instance(Token.Get (To_ID)) with
Value => (Value (Class(Token_List.Token_Handle(Left).all)) *
Value (Class(Token_List.Token_Handle(Right).all))
)
)
);
exception
when Constraint_Error =>
Ada.Exceptions.Raise_Exception
(Nonterminal.Invalid_Synth_Argument'Identity,
"Token " & Token.Token_ID'Image(To_ID) & " cannot be synthesized " &
"from a " &
Token.Token_ID'Image (Token.ID (Token_List.Token_Handle(Left).all) ) &
" and a " &
Token.Token_ID'Image (Token.ID (Token_List.Token_Handle(Right).all) ) &
"."
);
end Synthesize_Multiply;
procedure Synthesize_From_Second_Argument (New_Token : out Nonterminal.Class;
Source : in Token_List.Instance'Class;
To_ID : in Token.Token_ID) is
Second : Token_List.List_Iterator := Token_List.Initial_Iterator(Source);
begin
-- Move "Second" over to the second item;
Token_List.Next_Token (Second);
New_Token := Class(Instance'(Nonterminal.Instance(Nonterminal.Get(To_ID)) with
Value => Class(Token_List.Token_Handle(Second).all).Value));
exception
when Constraint_Error =>
Ada.Exceptions.Raise_Exception
(Nonterminal.Invalid_Synth_Argument'Identity,
"Token " & Token.Token_ID'Image(To_ID) & " cannot be synthesized " &
"solely from a " &
Token.Token_ID'Image
(Token.ID (Token_List.Token_Handle(Second).all) ) & ".");
end Synthesize_From_Second_Argument;
end Simple_Integer_Token;
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