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-------------------------------------------------------------------------------
--
-- Copyright (C) 2003 Stephen Leake
-- Copyright (C) 1999 FlightSafety International and 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.
--
-- This software was originally developed by the following company,
-- and was released as open-source software as a service to the
-- community:
--
-- FlightSafety International Simulation Systems Division
-- Broken Arrow, OK USA 918-259-4000
--
-------------------------------------------------------------------------------
package body OpenToken.Recognizer.Real is
overriding procedure Clear (The_Token : in out Instance) is
begin
Extended_Digits.Clear (The_Token.Decimal_Recognizer);
The_Token.Last_Verdict := Failed;
The_Token.State := First_Char;
end Clear;
overriding procedure Analyze
(The_Token : in out Instance;
Next_Char : in Character;
Verdict : out Analysis_Verdict)
is
Decimal_Verdict : Analysis_Verdict;
begin
case The_Token.State is
when First_Char =>
case Next_Char is
when '-' | '+' =>
if The_Token.Allow_Signs then
Verdict := So_Far_So_Good;
The_Token.State := First_Non_Sign;
Decimal_Verdict := Matches;
else
Verdict := Failed;
The_Token.State := Done;
end if;
when '.' =>
-- If the fore part is omitted and lazy reals are allowed, so-far-so-good...
if The_Token.Allow_Laziness then
Verdict := So_Far_So_Good;
The_Token.State := Aft_First;
else
Verdict := Failed;
The_Token.State := Done;
end if;
when others =>
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
-- If the fore part is an integer, so-far-so-good...
if Decimal_Verdict = Matches then
Verdict := So_Far_So_Good;
The_Token.State := Fore;
The_Token.Last_Verdict := Decimal_Verdict;
else
Verdict := Failed;
The_Token.State := Done;
end if;
end case;
when First_Non_Sign =>
-- If the fore part is omitted and lazy reals are allowed, so-far-so-good...
-- If the fore part is an integer, so-far-so-good...
if Next_Char = '.' then
if The_Token.Allow_Laziness then
Verdict := So_Far_So_Good;
The_Token.State := Aft_First;
else
Verdict := Failed;
The_Token.State := Done;
end if;
else
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
if Decimal_Verdict = Matches then
Verdict := So_Far_So_Good;
The_Token.State := Fore;
The_Token.Last_Verdict := Matches;
else
Verdict := Failed;
The_Token.State := Done;
end if;
end if;
when Fore =>
-- If the fore part is an integer, so-far-so-good...
-- Note that any state that leads into this one needs to set
-- The_Token.Last_Verdict to match the last verdict given
-- from The_Token.Decimal_Recognizer.
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
case Decimal_Verdict is
when So_Far_So_Good | -- Next_Char is '_'
Matches => -- or decimal digit
Verdict := So_Far_So_Good;
The_Token.Last_Verdict := Decimal_Verdict;
when Failed =>
if The_Token.Last_Verdict = Matches and Next_Char = '.' then
if The_Token.Allow_Laziness then
Verdict := Matches;
else
Verdict := So_Far_So_Good;
end if;
The_Token.State := Aft;
The_Token.Last_Verdict := Decimal_Verdict;
Extended_Digits.Clear (The_Token.Decimal_Recognizer);
elsif The_Token.Last_Verdict = Matches and
(Next_Char = 'e' or Next_Char = 'E') and
The_Token.Allow_Laziness and The_Token.Allow_Exponent then
Verdict := So_Far_So_Good;
The_Token.State := Exponent_Sign;
Extended_Digits.Clear (The_Token.Decimal_Recognizer);
else
Verdict := Failed;
The_Token.State := Done;
end if;
end case;
when Aft_First =>
-- We arrive here only for omitted fore part.
-- If the aft character is a digit, it matches.
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
if Decimal_Verdict = Matches then
Verdict := Matches;
The_Token.State := Aft;
The_Token.Last_Verdict := Matches;
else
Verdict := Failed;
The_Token.State := Done;
end if;
when Aft =>
-- If the aft character is a digit it matches.
-- If it is an underscore or an e/E, so-far-so-good...
-- Note that any state that leads into this one needs to set
-- The_Token.Last_Verdict to match the last verdict given from
-- The_Token.Decimal_Recognizer.
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
case Decimal_Verdict is
when So_Far_So_Good => -- Next_Char is '_'
Verdict := So_Far_So_Good;
The_Token.Last_Verdict := Decimal_Verdict;
when Matches => -- Next_Char is decimal digit
Verdict := Matches;
The_Token.Last_Verdict := Decimal_Verdict;
when Failed =>
if (The_Token.Last_Verdict = Matches or -- Aft present
(The_Token.Last_Verdict = Failed and -- Aft not present (but Fore present)
The_Token.Allow_Laziness)) and
(Next_Char = 'e' or Next_Char = 'E') and The_Token.Allow_Exponent then
Verdict := So_Far_So_Good;
The_Token.State := Exponent_Sign;
Extended_Digits.Clear (The_Token.Decimal_Recognizer);
else
Verdict := Failed;
The_Token.State := Done;
end if;
end case;
when Exponent_Sign =>
-- If the first exponent character is a sign, so-far-so-good...
-- If it is a decimal digit, it matches.
if Next_Char = '+' or Next_Char = '-' then
Verdict := So_Far_So_Good;
The_Token.State := Exponent;
else
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
if Decimal_Verdict = Matches then -- a decimal digit
Verdict := Matches;
The_Token.State := Exponent;
else
Verdict := Failed;
The_Token.State := Done;
end if;
end if;
when Exponent =>
-- If the exponent is a digit, it matches.
-- If it is an underscore, so-far-so-good...
Extended_Digits.Analyze (The_Token.Decimal_Recognizer, Next_Char, Decimal_Verdict);
case Decimal_Verdict is
when So_Far_So_Good | -- Next_Char is '_'
Matches => -- or decimal digit
Verdict := Decimal_Verdict;
when Failed =>
Verdict := Failed;
The_Token.State := Done;
end case;
when Done =>
-- We shouldn't get called from here.
Verdict := Failed;
end case;
end Analyze;
----------------------------------------------------------------------------
-- This procedure will be called to create a Real token
----------------------------------------------------------------------------
function Get (Allow_Underscores : Boolean := True;
Allow_Exponent : Boolean := True;
Allow_Signs : Boolean := True;
Allow_Laziness : Boolean := False) return Instance is
begin
return (Report => True,
Allow_Exponent => Allow_Exponent,
Allow_Laziness => Allow_Laziness,
Allow_Signs => Allow_Signs,
Decimal_Recognizer => Extended_Digits.Get (Allow_Underscores => Allow_Underscores,
For_Base => 10),
Last_Verdict => Failed,
State => First_Char);
end Get;
end OpenToken.Recognizer.Real;
|
