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|
#!/usr/bin/perl
use strict;
use Lexer;
use Tree;
use ParserTable;
my $debug = 0;
open ( data, "<input.txt" );
#Stores the list of tokens generated by lexer.
my @tokens;
while ( <data> )
{
push @tokens, lex($_);
}
if( $debug )
{
print "Lexer Output\n";
foreach my $token ( @tokens )
{
print join(" ", @{$token}), "\n";
}
}
push @tokens, ["end"];
my @stack = (0);
print "Parser Output\n" if $debug;
while ( @stack )
{
if($stack[-1] == $ParserTable::accept)
{
print "Complete\n";
printgraph( $stack[-4] );
last;
}
my @curr_token = @{ $tokens[0] };
if(my $val = $ParserTable::table[ $stack[-1] ]{ $curr_token[0] })
{
push @stack, \@curr_token, $val;
shift @tokens;
}
elsif(my $val = $ParserTable::table[ $stack[-1] ]{ reduce })
{
my @val1 = @$val;
my @param;
for(my $i = 1; $i <= 2 * $val1[0]; $i++)
{
if($i%2 == 0)
{
$val = pop @stack;
push @param,$val;
}
else
{
pop @stack;
}
}
@param = reverse @param;
push @stack, $val1[1]->( @param );
push @stack, $ParserTable::table[ $stack[-2] ]{ $stack[-1]->{ name }};
}
else
{
die "Unexpected Token ". @curr_token."\n";
}
print @stack, "\n" if $debug;
}
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