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|
-------------------------------------------------------------------------------
--
-- Copyright (C) 2006 Stephen Leake
--
-- 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.
package body OpenToken.Recognizer.Based_Integer is
overriding procedure Clear (The_Token : in out Instance) is
begin
The_Token :=
(Report => True,
Number_Recognizer => Extended_Digits.Get (Allow_Underscores => True, For_Base => 10),
Last_Verdict => Failed,
State => First_Char,
Base => 0,
Based => False);
end Clear;
overriding procedure Analyze
(The_Token : in out Instance;
Next_Char : in Character;
Verdict : out Analysis_Verdict)
is
Digits_Verdict : Analysis_Verdict := Failed;
begin
case The_Token.State is
when First_Char =>
case Next_Char is
when '-' | '+' =>
The_Token.State := Maybe_Base;
Verdict := So_Far_So_Good;
when others =>
Extended_Digits.Analyze
(The_Token => The_Token.Number_Recognizer,
Next_Char => Next_Char,
Verdict => Digits_Verdict);
if Digits_Verdict = Matches then
Verdict := Matches;
The_Token.State := Maybe_Base;
-- Keep a running total of the value, in case it is
-- the base.
The_Token.Base := (The_Token.Base * 10) + (Character'Pos (Next_Char) - Character'Pos ('0'));
else
Verdict := Failed;
The_Token.State := Done;
end if;
end case;
when Maybe_Base =>
Extended_Digits.Analyze (The_Token.Number_Recognizer, Next_Char, Digits_Verdict);
case Digits_Verdict is
when So_Far_So_Good =>
-- Next_Char is '_'
Verdict := So_Far_So_Good;
when Matches =>
-- Next_Char is a decimal digit
The_Token.Base := (The_Token.Base * 10) + (Character'Pos (Next_Char) - Character'Pos ('0'));
-- Test against maximum_base here, to avoid constraint
-- error on large integers.
Verdict := Matches;
if The_Token.Base > Extended_Digits.Maximum_Base then
The_Token.State := Numeral;
end if;
when Failed =>
-- Can't have "16_#"
if The_Token.Last_Verdict = Matches and Next_Char = '#' then
The_Token.Based := True;
-- Set up the subrecognizer for integers of the specified base
The_Token.Number_Recognizer := Extended_Digits.Get
(Allow_Underscores => True,
For_Base => The_Token.Base);
Verdict := So_Far_So_Good;
The_Token.State := Numeral;
else
Verdict := Failed;
The_Token.State := Done;
end if;
end case;
when Numeral =>
Extended_Digits.Analyze (The_Token.Number_Recognizer, Next_Char, Digits_Verdict);
case Digits_Verdict is
when So_Far_So_Good =>
-- Next_Char is '_'
Verdict := So_Far_So_Good;
when Matches =>
-- Next_Char extended digit
if The_Token.Based then
-- need trailing #
Verdict := So_Far_So_Good;
else
Verdict := Matches;
end if;
when Failed =>
if The_Token.Based then
if Next_Char = '#' then
if The_Token.Last_Verdict = Matches then
Verdict := Matches;
The_Token.State := Done;
else
-- last char was trailing '_'
Verdict := Failed;
The_Token.State := Done;
end if;
else
Verdict := Failed;
The_Token.State := Done;
end if;
else
Verdict := Failed;
The_Token.State := Done;
end if;
end case;
when Done =>
-- We shouldn't get here.
Verdict := Failed;
end case;
The_Token.Last_Verdict := Digits_Verdict;
end Analyze;
function Get return Instance
is begin
return
(Report => True,
Number_Recognizer => Extended_Digits.Get (Allow_Underscores => True, For_Base => 10),
Last_Verdict => Failed,
State => First_Char,
Base => 0,
Based => False);
end Get;
end OpenToken.Recognizer.Based_Integer;
|
