# # 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;