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-------------------------------------------------------------------------------
--
-- 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
--
-------------------------------------------------------------------------------
with OpenToken.Recognizer.Extended_Digits;
-----------------------------------------------------------------------------
-- This package implements a token recognizer for a real number. An
-- real is defined as a string starting with a series of digits,
-- followed by a decimal point and another series of digits,
-- optionally followed by an exponent specification. An exponent
-- specification is a letter 'e' (or 'E') followed by an optional
-- sign and decimal digits. Each of the sequences of digits may be
-- interspersed with one or more single underscores (but must not end
-- with an underscore), if not explicitly dis- allowed. Optionally
-- lazy reals can be allowed, i.e. reals where one of the fore or aft
-- parts may be omitted and, when fore and the exponent are defined,
-- also the dot may be omitted. When allowing lazy real, be careful
-- not to allow integers with exponents, or else a literal like 1e+10
-- is ambiguous.
-----------------------------------------------------------------------------
package OpenToken.Recognizer.Real is
type Instance is new OpenToken.Recognizer.Instance with private;
----------------------------------------------------------------------------
-- This procedure will be called to create a Real token.
--
-- One would probably want to disallow signs in languages that use
-- '-' or '+' as an operator between integers. If your syntax does
-- not have such a concept, you will probably want to allow them.
--------------------------------------------------------------------------
function Get (Allow_Underscores : Boolean := True;
Allow_Exponent : Boolean := True;
Allow_Signs : Boolean := True;
Allow_Laziness : Boolean := False) return Instance;
private
type State_ID is (First_Char, First_Non_Sign, Fore, Aft_First, Aft, Exponent_Sign, Exponent, Done);
type Instance is new OpenToken.Recognizer.Instance with record
Allow_Exponent : Boolean := True;
Allow_Laziness : Boolean := False;
Allow_Signs : Boolean := True;
-- The finite state machine state
Decimal_Recognizer : Extended_Digits.Instance; -- Fore, Aft, Exponent
Last_Verdict : Analysis_Verdict := Failed;
State : State_ID := First_Char;
end record;
overriding procedure Clear (The_Token : in out Instance);
overriding procedure
Analyze (The_Token : in out Instance;
Next_Char : in Character;
Verdict : out Analysis_Verdict);
end OpenToken.Recognizer.Real;
|
