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lib/AI/Prolog/Engine/Primitives.pm  view on Meta::CPAN

# mult(X,Y)  := 27.
# div(X,Y)   := 28.
# mod(X,Y)   := 29.

$PRIMITIVES[30] = sub {    # seq/1
    my ( $self, $term, $c ) = @_;
    $self->_splice_goal_list($term);
    CONTINUE;
};

my $HELP_OUTPUT;
$PRIMITIVES[31] = sub {    # help/0
    _load_builtins();
    if ( not $HELP_OUTPUT ) {
        $HELP_OUTPUT = "Help is available for the following builtins:\n\n";
        my @predicates = sort keys %DESCRIPTION_FOR;
        my $length     = length $LONGEST_PREDICATE;
        my $columns    = 5;
        my $format     = join '    ' => ("%-${length}s") x $columns;
        while (@predicates) {
            my @row;
            for ( 1 .. $columns ) {
                push @row => @predicates
                    ? shift @predicates
                    : '';
            }
            $HELP_OUTPUT .= sprintf $format => @row;
            $HELP_OUTPUT .= "\n";
        }
        $HELP_OUTPUT .= "\n";
    }
    AI::Prolog::Engine::_print($HELP_OUTPUT);
    CONTINUE;
};

$PRIMITIVES[32] = sub {    # help/1
    my ( $self, $term, $c ) = @_;
    my $predicate = $term->getarg(0)->to_string;
    _load_builtins();
    if ( my $description = $DESCRIPTION_FOR{$predicate} ) {
        AI::Prolog::Engine::_print($description);
    }