44d6a70684
* 5ataprop.adb, 5atpopsp.adb, 5ftaprop.adb, 5gmastop.adb, 5gtaprop.adb, 5htaprop.adb, 5itaprop.adb, 5lintman.adb, 5omastop.adb, 5oosinte.adb, 5otaprop.adb, 5staprop.adb, 5vinterr.adb, 5vtaprop.adb, 5vtpopde.adb, 5wintman.adb, 5wtaprop.adb, 5zinterr.adb, 5ztaprop.adb, 6vcstrea.adb, 7sintman.adb, 7staprop.adb, 9drpc.adb, ChangeLog, Makefile.in, a-except.adb, a-tags.ads, a-tasatt.adb, a-teioed.adb, a-textio.ads, a-witeio.ads, a-wtedit.adb, ali.ads, comperr.adb, cstand.adb, einfo.ads, errout.adb, exp_ch11.adb, exp_ch2.adb, exp_ch3.adb, exp_ch4.adb, exp_ch5.adb, exp_ch6.adb, exp_ch9.adb, exp_util.adb, exp_util.ads, fname-uf.adb, g-cgi.ads, g-exctra.ads, g-expect.ads, g-regist.adb, g-spipat.adb, gnatchop.adb, gnatlink.adb, gnatls.adb, gnatmain.adb, gnatmem.adb, init.c, make.adb, make.ads, mdlltool.adb, nlists.ads, osint.ads, par-ch3.adb, par-ch4.adb, par-ch5.adb, par-ch6.adb, par.adb, repinfo.adb, s-fatflt.ads, s-fatlfl.ads, s-fatllf.ads, s-fatsfl.ads, s-finimp.adb, s-finimp.ads, s-interr.adb, s-secsta.ads, s-shasto.ads, s-stalib.adb, s-stalib.ads, s-tarest.ads, s-tasdeb.adb, s-tassta.adb, s-tassta.ads, s-vaflop.ads, scans.ads, scn.adb, sem.ads, sem_aggr.adb, sem_attr.adb, sem_case.ads, sem_ch10.adb, sem_ch12.adb, sem_ch13.adb, sem_ch3.adb, sem_ch3.ads, sem_ch5.adb, sem_ch7.adb, sem_ch8.adb, sem_ch8.ads, sem_type.adb, sem_util.ads, sinfo.ads, sprint.adb, tbuild.ads, types.ads, utils.c, xeinfo.adb: Fix spelling errors. From-SVN: r48055
420 lines
19 KiB
Ada
420 lines
19 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S C A N S --
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-- --
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-- S p e c --
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-- --
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-- $Revision: 1.3 $
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-- --
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-- Copyright (C) 1992-2001 Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
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-- --
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------------------------------------------------------------------------------
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with Types; use Types;
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package Scans is
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-- The scanner maintains a current state in the global variables defined
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-- in this package. The call to the Scan routine advances this state to
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-- the next token. The state is initialized by the call to one of the
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-- initialization routines in Sinput.
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-- The following type is used to identify token types returned by Scan.
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-- The class column in this table indicates the token classes which
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-- apply to the token, as defined by subsquent subtype declarations.
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-- Note: the coding in SCN depends on the fact that the first entry in
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-- this type declaration is *not* for a reserved word. For details on
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-- why there is this requirement, see Scn.Initialize_Scanner.
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type Token_Type is (
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-- Token name Token type Class(es)
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Tok_Integer_Literal, -- numeric lit Literal, Lit_Or_Name
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Tok_Real_Literal, -- numeric lit Literal, Lit_Or_Name
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Tok_String_Literal, -- string lit Literal. Lit_Or_Name
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Tok_Char_Literal, -- char lit Name, Literal. Lit_Or_Name
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Tok_Operator_Symbol, -- op symbol Name, Literal, Lit_Or_Name, Desig
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Tok_Identifier, -- identifier Name, Lit_Or_Name, Desig
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Tok_Double_Asterisk, -- **
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Tok_Ampersand, -- & Binary_Addop
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Tok_Minus, -- - Binary_Addop, Unary_Addop
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Tok_Plus, -- + Binary_Addop, Unary_Addop
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Tok_Asterisk, -- * Mulop
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Tok_Mod, -- MOD Mulop
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Tok_Rem, -- REM Mulop
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Tok_Slash, -- / Mulop
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Tok_New, -- NEW
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Tok_Abs, -- ABS
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Tok_Others, -- OTHERS
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Tok_Null, -- NULL
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Tok_Dot, -- . Namext
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Tok_Apostrophe, -- ' Namext
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Tok_Left_Paren, -- ( Namext, Consk
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Tok_Delta, -- DELTA Atkwd, Sterm, Consk
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Tok_Digits, -- DIGITS Atkwd, Sterm, Consk
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Tok_Range, -- RANGE Atkwd, Sterm, Consk
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Tok_Right_Paren, -- ) Sterm
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Tok_Comma, -- , Sterm
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Tok_And, -- AND Logop, Sterm
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Tok_Or, -- OR Logop, Sterm
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Tok_Xor, -- XOR Logop, Sterm
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Tok_Less, -- < Relop, Sterm
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Tok_Equal, -- = Relop, Sterm
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Tok_Greater, -- > Relop, Sterm
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Tok_Not_Equal, -- /= Relop, Sterm
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Tok_Greater_Equal, -- >= Relop, Sterm
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Tok_Less_Equal, -- <= Relop, Sterm
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Tok_In, -- IN Relop, Sterm
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Tok_Not, -- NOT Relop, Sterm
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Tok_Box, -- <> Relop, Eterm, Sterm
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Tok_Colon_Equal, -- := Eterm, Sterm
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Tok_Colon, -- : Eterm, Sterm
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Tok_Greater_Greater, -- >> Eterm, Sterm
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Tok_Abstract, -- ABSTRACT Eterm, Sterm
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Tok_Access, -- ACCESS Eterm, Sterm
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Tok_Aliased, -- ALIASED Eterm, Sterm
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Tok_All, -- ALL Eterm, Sterm
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Tok_Array, -- ARRAY Eterm, Sterm
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Tok_At, -- AT Eterm, Sterm
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Tok_Body, -- BODY Eterm, Sterm
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Tok_Constant, -- CONSTANT Eterm, Sterm
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Tok_Do, -- DO Eterm, Sterm
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Tok_Is, -- IS Eterm, Sterm
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Tok_Limited, -- LIMITED Eterm, Sterm
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Tok_Of, -- OF Eterm, Sterm
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Tok_Out, -- OUT Eterm, Sterm
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Tok_Record, -- RECORD Eterm, Sterm
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Tok_Renames, -- RENAMES Eterm, Sterm
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Tok_Reverse, -- REVERSE Eterm, Sterm
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Tok_Tagged, -- TAGGED Eterm, Sterm
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Tok_Then, -- THEN Eterm, Sterm
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Tok_Less_Less, -- << Eterm, Sterm, After_SM
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Tok_Abort, -- ABORT Eterm, Sterm, After_SM
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Tok_Accept, -- ACCEPT Eterm, Sterm, After_SM
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Tok_Case, -- CASE Eterm, Sterm, After_SM
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Tok_Delay, -- DELAY Eterm, Sterm, After_SM
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Tok_Else, -- ELSE Eterm, Sterm, After_SM
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Tok_Elsif, -- ELSIF Eterm, Sterm, After_SM
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Tok_End, -- END Eterm, Sterm, After_SM
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Tok_Exception, -- EXCEPTION Eterm, Sterm, After_SM
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Tok_Exit, -- EXIT Eterm, Sterm, After_SM
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Tok_Goto, -- GOTO Eterm, Sterm, After_SM
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Tok_If, -- IF Eterm, Sterm, After_SM
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Tok_Pragma, -- PRAGMA Eterm, Sterm, After_SM
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Tok_Raise, -- RAISE Eterm, Sterm, After_SM
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Tok_Requeue, -- REQUEUE Eterm, Sterm, After_SM
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Tok_Return, -- RETURN Eterm, Sterm, After_SM
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Tok_Select, -- SELECT Eterm, Sterm, After_SM
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Tok_Terminate, -- TERMINATE Eterm, Sterm, After_SM
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Tok_Until, -- UNTIL Eterm, Sterm, After_SM
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Tok_When, -- WHEN Eterm, Sterm, After_SM
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Tok_Begin, -- BEGIN Eterm, Sterm, After_SM, Labeled_Stmt
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Tok_Declare, -- DECLARE Eterm, Sterm, After_SM, Labeled_Stmt
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Tok_For, -- FOR Eterm, Sterm, After_SM, Labeled_Stmt
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Tok_Loop, -- LOOP Eterm, Sterm, After_SM, Labeled_Stmt
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Tok_While, -- WHILE Eterm, Sterm, After_SM, Labeled_Stmt
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Tok_Entry, -- ENTRY Eterm, Sterm, Declk, Deckn, After_SM
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Tok_Protected, -- PROTECTED Eterm, Sterm, Declk, Deckn, After_SM
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Tok_Task, -- TASK Eterm, Sterm, Declk, Deckn, After_SM
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Tok_Type, -- TYPE Eterm, Sterm, Declk, Deckn, After_SM
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Tok_Subtype, -- SUBTYPE Eterm, Sterm, Declk, Deckn, After_SM
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Tok_Use, -- USE Eterm, Sterm, Declk, Deckn, After_SM
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Tok_Function, -- FUNCTION Eterm, Sterm, Cunit, Declk, After_SM
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Tok_Generic, -- GENERIC Eterm, Sterm, Cunit, Declk, After_SM
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Tok_Package, -- PACKAGE Eterm, Sterm, Cunit, Declk, After_SM
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Tok_Procedure, -- PROCEDURE Eterm, Sterm, Cunit, Declk, After_SM
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Tok_Private, -- PRIVATE Eterm, Sterm, Cunit, After_SM
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Tok_With, -- WITH Eterm, Sterm, Cunit, After_SM
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Tok_Separate, -- SEPARATE Eterm, Sterm, Cunit, After_SM
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Tok_EOF, -- End of file Eterm, Sterm, Cterm, After_SM
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Tok_Semicolon, -- ; Eterm, Sterm, Cterm
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Tok_Arrow, -- => Sterm, Cterm, Chtok
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Tok_Vertical_Bar, -- | Cterm, Sterm, Chtok
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Tok_Dot_Dot, -- .. Sterm, Chtok
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-- The following three entries are used only when scanning
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-- project files.
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Tok_Project,
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Tok_Extends,
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Tok_External,
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No_Token);
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-- No_Token is used for initializing Token values to indicate that
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-- no value has been set yet.
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-- Note: in the RM, operator symbol is a special case of string literal.
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-- We distinguish at the lexical level in this compiler, since there are
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-- many syntactic situations in which only an operator symbol is allowed.
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-- The following subtype declarations group the token types into classes.
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-- These are used for class tests in the parser.
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subtype Token_Class_Numeric_Literal is
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Token_Type range Tok_Integer_Literal .. Tok_Real_Literal;
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-- Numeric literal
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subtype Token_Class_Literal is
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Token_Type range Tok_Integer_Literal .. Tok_Operator_Symbol;
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-- Literal
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subtype Token_Class_Lit_Or_Name is
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Token_Type range Tok_Integer_Literal .. Tok_Identifier;
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subtype Token_Class_Binary_Addop is
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Token_Type range Tok_Ampersand .. Tok_Plus;
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-- Binary adding operator (& + -)
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subtype Token_Class_Unary_Addop is
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Token_Type range Tok_Minus .. Tok_Plus;
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-- Unary adding operator (+ -)
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subtype Token_Class_Mulop is
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Token_Type range Tok_Asterisk .. Tok_Slash;
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-- Multiplying operator
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subtype Token_Class_Logop is
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Token_Type range Tok_And .. Tok_Xor;
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-- Logical operator (and, or, xor)
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subtype Token_Class_Relop is
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Token_Type range Tok_Less .. Tok_Box;
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-- Relational operator (= /= < <= > >= not, in plus <> to catch misuse
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-- of Pascal style not equal operator).
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subtype Token_Class_Name is
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Token_Type range Tok_Char_Literal .. Tok_Identifier;
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-- First token of name (4.1),
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-- (identifier, char literal, operator symbol)
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subtype Token_Class_Desig is
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Token_Type range Tok_Operator_Symbol .. Tok_Identifier;
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-- Token which can be a Designator (identifier, operator symbol)
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subtype Token_Class_Namext is
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Token_Type range Tok_Dot .. Tok_Left_Paren;
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-- Name extension tokens. These are tokens which can appear immediately
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-- after a name to extend it recursively (period, quote, left paren)
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subtype Token_Class_Consk is
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Token_Type range Tok_Left_Paren .. Tok_Range;
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-- Keywords which can start constraint
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-- (left paren, delta, digits, range)
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subtype Token_Class_Eterm is
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Token_Type range Tok_Colon_Equal .. Tok_Semicolon;
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-- Expression terminators. These tokens can never appear within a simple
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-- expression. This is used for error recovery purposes (if we encounter
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-- an error in an expression, we simply scan to the next Eterm token).
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subtype Token_Class_Sterm is
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Token_Type range Tok_Delta .. Tok_Dot_Dot;
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-- Simple_Expression terminators. A Simple_Expression must be followed
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-- by a token in this class, or an error message is issued complaining
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-- about a missing binary operator.
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subtype Token_Class_Atkwd is
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Token_Type range Tok_Delta .. Tok_Range;
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-- Attribute keywords. This class includes keywords which can be used
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-- as an Attribute_Designator, namely DELTA, DIGITS and RANGE
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subtype Token_Class_Cterm is
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Token_Type range Tok_EOF .. Tok_Vertical_Bar;
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-- Choice terminators. These tokens terminate a choice. This is used for
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-- error recovery purposes (if we encounter an error in a Choice, we
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-- simply scan to the next Cterm token).
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subtype Token_Class_Chtok is
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Token_Type range Tok_Arrow .. Tok_Dot_Dot;
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-- Choice tokens. These tokens signal a choice when used in an Aggregate
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subtype Token_Class_Cunit is
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Token_Type range Tok_Function .. Tok_Separate;
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-- Tokens which can begin a compilation unit
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subtype Token_Class_Declk is
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Token_Type range Tok_Entry .. Tok_Procedure;
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-- Keywords which start a declaration
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subtype Token_Class_Deckn is
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Token_Type range Tok_Entry .. Tok_Use;
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-- Keywords which start a declaration but can't start a compilation unit
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subtype Token_Class_After_SM is
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Token_Type range Tok_Less_Less .. Tok_EOF;
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-- Tokens which always, or almost always, appear after a semicolon. Used
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-- in the Resync_Past_Semicolon routine to avoid gobbling up stuff when
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-- a semicolon is missing. Of significance only for error recovery.
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subtype Token_Class_Labeled_Stmt is
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Token_Type range Tok_Begin .. Tok_While;
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-- Tokens which start labeled statements
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type Token_Flag_Array is array (Token_Type) of Boolean;
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Is_Reserved_Keyword : constant Token_Flag_Array := Token_Flag_Array'(
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Tok_Mod .. Tok_Rem => True,
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Tok_New .. Tok_Null => True,
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Tok_Delta .. Tok_Range => True,
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Tok_And .. Tok_Xor => True,
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Tok_In .. Tok_Not => True,
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Tok_Abstract .. Tok_Then => True,
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Tok_Abort .. Tok_Separate => True,
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others => False);
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-- Flag array used to test for reserved word
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--------------------------
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-- Scan State Variables --
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--------------------------
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-- Note: these variables can only be referenced during the parsing of a
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-- file. Reference to any of them from Sem or the expander is wrong.
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Scan_Ptr : Source_Ptr;
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-- Current scan pointer location. After a call to Scan, this points
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-- just past the end of the token just scanned.
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Token : Token_Type;
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-- Type of current token
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Token_Ptr : Source_Ptr;
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-- Pointer to first character of current token
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Current_Line_Start : Source_Ptr;
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-- Pointer to first character of line containing current token
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Start_Column : Column_Number;
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-- Starting column number (zero origin) of the first non-blank character
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-- on the line containing the current token. This is used for error
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-- recovery circuits which depend on looking at the column line up.
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Checksum : Word;
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-- Used to accumulate a CRC representing the tokens in the source
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-- file being compiled. This CRC includes only program tokens, and
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-- excludes comments.
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First_Non_Blank_Location : Source_Ptr;
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-- Location of first non-blank character on the line containing the
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-- current token (i.e. the location of the character whose column number
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-- is stored in Start_Column).
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Token_Node : Node_Id := Empty;
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-- Node table Id for the current token. This is set only if the current
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-- token is one for which the scanner constructs a node (i.e. it is an
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-- identifier, operator symbol, or literal. For other token types,
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-- Token_Node is undefined.
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Token_Name : Name_Id := No_Name;
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-- For identifiers, this is set to the Name_Id of the identifier scanned.
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-- For all other tokens, Token_Name is set to Error_Name. Note that it
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-- would be possible for the caller to extract this information from
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-- Token_Node. We set Token_Name separately for two reasons. First it
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-- allows a quicker test for a specific identifier. Second, it allows
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-- a version of the parser to be built that does not build tree nodes,
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-- usable as a syntax checker.
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Prev_Token : Token_Type := No_Token;
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-- Type of previous token
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Prev_Token_Ptr : Source_Ptr;
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-- Pointer to first character of previous token
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Version_To_Be_Found : Boolean;
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-- This flag is True if the scanner is still looking for an RCS version
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-- number in a comment. Normally it is initialized to False so that this
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-- circuit is not activated. If the -dv switch is set, then this flag is
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-- initialized to True, and then reset when the version number is found.
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-- We do things this way to minimize the impact on comment scanning.
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--------------------------------------------------------
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-- Procedures for Saving and Restoring the Scan State --
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--------------------------------------------------------
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-- The following procedures can be used to save and restore the entire
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-- scan state. They are used in cases where it is necessary to backup
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-- the scan during the parse.
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type Saved_Scan_State is private;
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-- Used for saving and restoring the scan state
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procedure Save_Scan_State (Saved_State : out Saved_Scan_State);
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pragma Inline (Save_Scan_State);
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-- Saves the current scan state for possible later restoration. Note that
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-- there is no harm in saving the state and then never restoring it.
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procedure Restore_Scan_State (Saved_State : in Saved_Scan_State);
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pragma Inline (Restore_Scan_State);
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-- Restores a scan state saved by a call to Save_Scan_State.
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-- The saved scan state must refer to the current source file.
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private
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type Saved_Scan_State is record
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Save_Scan_Ptr : Source_Ptr;
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Save_Token : Token_Type;
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Save_Token_Ptr : Source_Ptr;
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Save_Current_Line_Start : Source_Ptr;
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Save_Start_Column : Column_Number;
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Save_Checksum : Word;
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Save_First_Non_Blank_Location : Source_Ptr;
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Save_Token_Node : Node_Id;
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Save_Token_Name : Name_Id;
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Save_Prev_Token : Token_Type;
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Save_Prev_Token_Ptr : Source_Ptr;
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end record;
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end Scans;
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