#
# Module Parse::Yapp::Driver
#
# This module is part of the Parse::Yapp package available on your
# nearest CPAN
#
# Any use of this module in a standalone parser make the included
# text under the same copyright as the Parse::Yapp module itself.
#
# This notice should remain unchanged.
#
# (c) Copyright 1998-2001 Francois Desarmenien, all rights reserved.
# (see the pod text in Parse::Yapp module for use and distribution rights)
#
package Parse::Yapp::Driver;
require 5.004;
use strict;
use vars qw ( $VERSION $COMPATIBLE $FILENAME );
$VERSION = '1.05';
$COMPATIBLE = '0.07';
$FILENAME=__FILE__;
use Carp;
#Known parameters, all starting with YY (leading YY will be discarded)
my(%params)=(YYLEX => 'CODE', 'YYERROR' => 'CODE', YYVERSION => '',
YYRULES => 'ARRAY', YYSTATES => 'ARRAY', YYDEBUG => '');
#Mandatory parameters
my(@params)=('LEX','RULES','STATES');
sub new {
my($class)=shift;
my($errst,$nberr,$token,$value,$check,$dotpos);
my($self)={ ERROR => \&_Error,
ERRST => \$errst,
NBERR => \$nberr,
TOKEN => \$token,
VALUE => \$value,
DOTPOS => \$dotpos,
STACK => [],
DEBUG => 0,
CHECK => \$check };
_CheckParams( [], \%params, \@_, $self );
exists($$self{VERSION})
and $$self{VERSION} < $COMPATIBLE
and croak "Yapp driver version $VERSION ".
"incompatible with version $$self{VERSION}:\n".
"Please recompile parser module.";
ref($class)
and $class=ref($class);
bless($self,$class);
}
sub YYParse {
my($self)=shift;
my($retval);
_CheckParams( \@params, \%params, \@_, $self );
if($$self{DEBUG}) {
_DBLoad();
$retval = eval '$self->_DBParse()';#Do not create stab entry on compile
$@ and die $@;
}
else {
$retval = $self->_Parse();
}
$retval
}
sub YYData {
my($self)=shift;
exists($$self{USER})
or $$self{USER}={};
$$self{USER};
}
sub YYErrok {
my($self)=shift;
${$$self{ERRST}}=0;
undef;
}
sub YYNberr {
my($self)=shift;
${$$self{NBERR}};
}
sub YYRecovering {
my($self)=shift;
${$$self{ERRST}} != 0;
}
sub YYAbort {
my($self)=shift;
${$$self{CHECK}}='ABORT';
undef;
}
sub YYAccept {
my($self)=shift;
${$$self{CHECK}}='ACCEPT';
undef;
}
sub YYError {
my($self)=shift;
${$$self{CHECK}}='ERROR';
undef;
}
sub YYSemval {
my($self)=shift;
my($index)= $_[0] - ${$$self{DOTPOS}} - 1;
$index < 0
and -$index <= @{$$self{STACK}}
and return $$self{STACK}[$index][1];
undef; #Invalid index
}
sub YYCurtok {
my($self)=shift;
@_
and ${$$self{TOKEN}}=$_[0];
${$$self{TOKEN}};
}
sub YYCurval {
my($self)=shift;
@_
and ${$$self{VALUE}}=$_[0];
${$$self{VALUE}};
}
sub YYExpect {
my($self)=shift;
keys %{$self->{STATES}[$self->{STACK}[-1][0]]{ACTIONS}}
}
sub YYLexer {
my($self)=shift;
$$self{LEX};
}
#################
# Private stuff #
#################
sub _CheckParams {
my($mandatory,$checklist,$inarray,$outhash)=@_;
my($prm,$value);
my($prmlst)={};
while(($prm,$value)=splice(@$inarray,0,2)) {
$prm=uc($prm);
exists($$checklist{$prm})
or croak("Unknow parameter '$prm'");
ref($value) eq $$checklist{$prm}
or croak("Invalid value for parameter '$prm'");
$prm=unpack('@2A*',$prm);
$$outhash{$prm}=$value;
}
for (@$mandatory) {
exists($$outhash{$_})
or croak("Missing mandatory parameter '".lc($_)."'");
}
}
sub _Error {
print "Parse error.\n";
}
sub _DBLoad {
{
no strict 'refs';
exists(${__PACKAGE__.'::'}{_DBParse})#Already loaded ?
and return;
}
my($fname)=__FILE__;
my(@drv);
open(DRV,"<$fname") or die "Report this as a BUG: Cannot open $fname";
while(<DRV>) {
/^\s*sub\s+_Parse\s*{\s*$/ .. /^\s*}\s*#\s*_Parse\s*$/
and do {
s/^#DBG>//;
push(@drv,$_);
}
}
close(DRV);
$drv[0]=~s/_P/_DBP/;
eval join('',@drv);
}
#Note that for loading debugging version of the driver,
#this file will be parsed from 'sub _Parse' up to '}#_Parse' inclusive.
#So, DO NOT remove comment at end of sub !!!
sub _Parse {
my($self)=shift;
my($rules,$states,$lex,$error)
= @$self{ 'RULES', 'STATES', 'LEX', 'ERROR' };
my($errstatus,$nberror,$token,$value,$stack,$check,$dotpos)
= @$self{ 'ERRST', 'NBERR', 'TOKEN', 'VALUE', 'STACK', 'CHECK', 'DOTPOS' };
#DBG> my($debug)=$$self{DEBUG};
#DBG> my($dbgerror)=0;
#DBG> my($ShowCurToken) = sub {
#DBG> my($tok)='>';
#DBG> for (split('',$$token)) {
#DBG> $tok.= (ord($_) < 32 or ord($_) > 126)
#DBG> ? sprintf('<%02X>',ord($_))
#DBG> : $_;
#DBG> }
#DBG> $tok.='<';
#DBG> };
$$errstatus=0;
$$nberror=0;
($$token,$$value)=(undef,undef);
@$stack=( [ 0, undef ] );
$$check='';
while(1) {
my($actions,$act,$stateno);
$stateno=$$stack[-1][0];
$actions=$$states[$stateno];
#DBG> print STDERR ('-' x 40),"\n";
#DBG> $debug & 0x2
#DBG> and print STDERR "In state $stateno:\n";
#DBG> $debug & 0x08
#DBG> and print STDERR "Stack:[".
#DBG> join(',',map { $$_[0] } @$stack).
#DBG> "]\n";
if (exists($$actions{ACTIONS})) {
defined($$token)
or do {
($$token,$$value)=&$lex($self);
#DBG> $debug & 0x01
#DBG> and print STDERR "Need token. Got ".&$ShowCurToken."\n";
};
$act= exists($$actions{ACTIONS}{$$token})
? $$actions{ACTIONS}{$$token}
: exists($$actions{DEFAULT})
? $$actions{DEFAULT}
: undef;
}
else {
$act=$$actions{DEFAULT};
#DBG> $debug & 0x01
#DBG> and print STDERR "Don't need token.\n";
}
defined($act)
and do {
$act > 0
and do { #shift
#DBG> $debug & 0x04
#DBG> and print STDERR "Shift and go to state $act.\n";
$$errstatus
and do {
--$$errstatus;
#DBG> $debug & 0x10
#DBG> and $dbgerror
#DBG> and $$errstatus == 0
#DBG> and do {
#DBG> print STDERR "**End of Error recovery.\n";
#DBG> $dbgerror=0;
#DBG> };
};
push(@$stack,[ $act, $$value ]);
$$token ne '' #Don't eat the eof
and $$token=$$value=undef;
next;
};
#reduce
my($lhs,$len,$code,@sempar,$semval);
($lhs,$len,$code)=@{$$rules[-$act]};
#DBG> $debug & 0x04
#DBG> and $act
#DBG> and print STDERR "Reduce using rule ".-$act." ($lhs,$len): ";
$act
or $self->YYAccept();
$$dotpos=$len;
unpack('A1',$lhs) eq '@' #In line rule
and do {
$lhs =~ /^\@[0-9]+\-([0-9]+)$/
or die "In line rule name '$lhs' ill formed: ".
"report it as a BUG.\n";
$$dotpos = $1;
};
@sempar = $$dotpos
? map { $$_[1] } @$stack[ -$$dotpos .. -1 ]
: ();
$semval = $code ? &$code( $self, @sempar )
: @sempar ? $sempar[0] : undef;
splice(@$stack,-$len,$len);
$$check eq 'ACCEPT'
and do {
#DBG> $debug & 0x04
#DBG> and print STDERR "Accept.\n";
return($semval);
};
$$check eq 'ABORT'
and do {
#DBG> $debug & 0x04
#DBG> and print STDERR "Abort.\n";
return(undef);
};
#DBG> $debug & 0x04
#DBG> and print STDERR "Back to state $$stack[-1][0], then ";
$$check eq 'ERROR'
or do {
#DBG> $debug & 0x04
#DBG> and print STDERR
#DBG> "go to state $$states[$$stack[-1][0]]{GOTOS}{$lhs}.\n";
#DBG> $debug & 0x10
#DBG> and $dbgerror
#DBG> and $$errstatus == 0
#DBG> and do {
#DBG> print STDERR "**End of Error recovery.\n";
#DBG> $dbgerror=0;
#DBG> };
push(@$stack,
[ $$states[$$stack[-1][0]]{GOTOS}{$lhs}, $semval ]);
$$check='';
next;
};
#DBG> $debug & 0x04
#DBG> and print STDERR "Forced Error recovery.\n";
$$check='';
};
#Error
$$errstatus
or do {
$$errstatus = 1;
&$error($self);
$$errstatus # if 0, then YYErrok has been called
or next; # so continue parsing
#DBG> $debug & 0x10
#DBG> and do {
#DBG> print STDERR "**Entering Error recovery.\n";
#DBG> ++$dbgerror;
#DBG> };
++$$nberror;
};
$$errstatus == 3 #The next token is not valid: discard it
and do {
$$token eq '' # End of input: no hope
and do {
#DBG> $debug & 0x10
#DBG> and print STDERR "**At eof: aborting.\n";
return(undef);
};
#DBG> $debug & 0x10
#DBG> and print STDERR "**Dicard invalid token ".&$ShowCurToken.".\n";
$$token=$$value=undef;
};
$$errstatus=3;
while( @$stack
and ( not exists($$states[$$stack[-1][0]]{ACTIONS})
or not exists($$states[$$stack[-1][0]]{ACTIONS}{error})
or $$states[$$stack[-1][0]]{ACTIONS}{error} <= 0)) {
#DBG> $debug & 0x10
#DBG> and print STDERR "**Pop state $$stack[-1][0].\n";
pop(@$stack);
}
@$stack
or do {
#DBG> $debug & 0x10
#DBG> and print STDERR "**No state left on stack: aborting.\n";
return(undef);
};
#shift the error token
#DBG> $debug & 0x10
#DBG> and print STDERR "**Shift \$error token and go to state ".
#DBG> $$states[$$stack[-1][0]]{ACTIONS}{error}.
#DBG> ".\n";
push(@$stack, [ $$states[$$stack[-1][0]]{ACTIONS}{error}, undef ]);
}
#never reached
croak("Error in driver logic. Please, report it as a BUG");
}#_Parse
#DO NOT remove comment
1;