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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- P A R . S Y N C --
-- --
-- B o d y --
-- --
-- $Revision: 1.19 $
-- --
-- Copyright (C) 1992-2001 Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT 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 GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
separate (Par)
package body Sync is
procedure Resync_Init;
-- This routine is called on initiating a resynchronization action
procedure Resync_Resume;
-- This routine is called on completing a resynchronization action
-------------------
-- Resync_Choice --
-------------------
procedure Resync_Choice is
begin
Resync_Init;
-- Loop till we get a token that terminates a choice. Note that EOF is
-- one such token, so we are sure to get out of this loop eventually!
while Token not in Token_Class_Cterm loop
Scan;
end loop;
Resync_Resume;
end Resync_Choice;
------------------
-- Resync_Cunit --
------------------
procedure Resync_Cunit is
begin
Resync_Init;
while Token not in Token_Class_Cunit
and then Token /= Tok_EOF
loop
Scan;
end loop;
Resync_Resume;
end Resync_Cunit;
-----------------------
-- Resync_Expression --
-----------------------
procedure Resync_Expression is
Paren_Count : Int;
begin
Resync_Init;
Paren_Count := 0;
loop
-- Terminating tokens are those in class Eterm and also RANGE,
-- DIGITS or DELTA if not preceded by an apostrophe (if they are
-- preceded by an apostrophe, then they are attributes). In addiion,
-- at the outer parentheses level only, we also consider a comma,
-- right parenthesis or vertical bar to terminate an expression.
if Token in Token_Class_Eterm
or else (Token in Token_Class_Atkwd
and then Prev_Token /= Tok_Apostrophe)
or else (Paren_Count = 0
and then
(Token = Tok_Comma
or else Token = Tok_Right_Paren
or else Token = Tok_Vertical_Bar))
then
-- A special check: if we stop on the ELSE of OR ELSE or the
-- THEN of AND THEN, keep going, because this is not really an
-- expression terminator after all. Also, keep going past WITH
-- since this can be part of an extension aggregate
if (Token = Tok_Else and then Prev_Token = Tok_Or)
or else (Token = Tok_Then and then Prev_Token = Tok_And)
or else Token = Tok_With
then
null;
else
exit;
end if;
end if;
if Token = Tok_Left_Paren then
Paren_Count := Paren_Count + 1;
elsif Token = Tok_Right_Paren then
Paren_Count := Paren_Count - 1;
end if;
Scan; -- past token to be skipped
end loop;
Resync_Resume;
end Resync_Expression;
-----------------
-- Resync_Init --
-----------------
procedure Resync_Init is
begin
-- The following check makes sure we do not get stuck in an infinite
-- loop resynchonizing and getting nowhere. If we are called to do a
-- resynchronize and we are exactly at the same point that we left off
-- on the last resynchronize call, then we force at least one token to
-- be skipped so that we make progress!
if Token_Ptr = Last_Resync_Point then
Scan; -- to skip at least one token
end if;
-- Output extra error message if debug R flag is set
if Debug_Flag_R then
Error_Msg_SC ("resynchronizing!");
end if;
end Resync_Init;
---------------------------
-- Resync_Past_Semicolon --
---------------------------
procedure Resync_Past_Semicolon is
begin
Resync_Init;
loop
-- Done if we are at a semicolon
if Token = Tok_Semicolon then
Scan; -- past semicolon
exit;
-- Done if we are at a token which normally appears only after
-- a semicolon. One special glitch is that the keyword private is
-- in this category only if it does NOT appear after WITH.
elsif Token in Token_Class_After_SM
and then (Token /= Tok_Private or else Prev_Token /= Tok_With)
then
exit;
-- Otherwise keep going
else
Scan;
end if;
end loop;
-- Fall out of loop with resyncrhonization complete
Resync_Resume;
end Resync_Past_Semicolon;
----------------------------------------------
-- Resync_Past_Semicolon_Or_To_Loop_Or_Then --
----------------------------------------------
procedure Resync_Past_Semicolon_Or_To_Loop_Or_Then is
begin
Resync_Init;
loop
-- Done if at semicolon
if Token = Tok_Semicolon then
Scan; -- past the semicolon
exit;
-- Done if we are at a token which normally appears only after
-- a semicolon. One special glitch is that the keyword private is
-- in this category only if it does NOT appear after WITH.
elsif (Token in Token_Class_After_SM
and then (Token /= Tok_Private
or else Prev_Token /= Tok_With))
then
exit;
-- Done if we are at THEN or LOOP
elsif Token = Tok_Then or else Token = Tok_Loop then
exit;
-- Otherwise keep going
else
Scan;
end if;
end loop;
-- Fall out of loop with resyncrhonization complete
Resync_Resume;
end Resync_Past_Semicolon_Or_To_Loop_Or_Then;
-------------------
-- Resync_Resume --
-------------------
procedure Resync_Resume is
begin
-- Save resync point (see special test in Resync_Init)
Last_Resync_Point := Token_Ptr;
if Debug_Flag_R then
Error_Msg_SC ("resuming here!");
end if;
end Resync_Resume;
--------------------
-- Resync_To_When --
--------------------
procedure Resync_To_When is
begin
Resync_Init;
loop
-- Done if at semicolon, WHEN or IS
if Token = Tok_Semicolon
or else Token = Tok_When
or else Token = Tok_Is
then
exit;
-- Otherwise keep going
else
Scan;
end if;
end loop;
-- Fall out of loop with resyncrhonization complete
Resync_Resume;
end Resync_To_When;
---------------------------
-- Resync_Semicolon_List --
---------------------------
procedure Resync_Semicolon_List is
Paren_Count : Int;
begin
Resync_Init;
Paren_Count := 0;
loop
if Token = Tok_EOF
or else Token = Tok_Semicolon
or else Token = Tok_Is
or else Token in Token_Class_After_SM
then
exit;
elsif Token = Tok_Left_Paren then
Paren_Count := Paren_Count + 1;
elsif Token = Tok_Right_Paren then
if Paren_Count = 0 then
exit;
else
Paren_Count := Paren_Count - 1;
end if;
end if;
Scan;
end loop;
Resync_Resume;
end Resync_Semicolon_List;
end Sync;
|
