#!/usr/bin/perl
package Sexpr;

use strict; use warnings;
use SexprNode;
use Carp;

sub new {
    my $class = shift;
    my $sexprt = {_root => undef};
    bless $sexprt, $class;
    return $sexprt;
}

sub set_root {
    my $sexprt = shift;
    my $sexprn = shift;
    unless (ref $sexprn eq 'SexprNode'){
	croak "method set_root() requires a SexprNode ref";
    }
    $sexprt->{_root} = $sexprn;
}

sub DESTROY {
    my $sexprt = shift;
    $sexprt->{_root}->DESTROY;
}

sub read_wsjsynt {
    my $sexprt = shift; my $fileh = shift;
    my @sexprnstack = ();
    my $inputl = <$fileh>;
    chomp($inputl);
    $inputl =~ s/\s+/ /g;
    while ($inputl){
	$inputl =~ s/^\s+//; $inputl =~ s/\s+$//; 
	if ($inputl =~ /^\(([^ \(\)]+) ([^ \(\)]+)\)/){ # terminal node
	    my $label = $1 . " " . $2;
	    my $sexprn = SexprNode->new($label);
	    if (my $super = pop @sexprnstack){
		$super->attachsexprn($sexprn);
		push @sexprnstack, $super;
	    }else{
		croak "method read_wsjsynt(): root terminal in $inputl";
	    }
	    $inputl = $'; # $' i.e. $POSTMATCH
	}elsif ($inputl =~ /^\(([^ \(\)]+)/){ # nonterminal node
	    my $label = $1;
	    my $sexprn = SexprNode->new($label);
	    push @sexprnstack, $sexprn;
	    $inputl = $'; # $' i.e. $POSTMATCH
	}elsif ($inputl =~ /^\)/){
	    my $sexprn = pop @sexprnstack; 
	    if (@sexprnstack){
		$sexprnstack[$#sexprnstack]->attachsexprn($sexprn);
	    }else{
		$sexprt->{_root} = $sexprn;
	    }
	    $inputl = $'; # $' i.e. $POSTMATCH
	}else{
	    croak "method read_wsjsynt(): unknown token in $inputl";
	}
    }
}
sub dfs {
	my $sexprt = shift;
	return $sexprt->{_root}->dfs;
}
sub prettystring {
	my $sexprt = shift;
	return $sexprt->{_root}->prettystring('  ');
}
1;