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lib/ABNF/Generator.pm  view on Meta::CPAN

=pod

=head1 ABNF::Generator->C<new>($grammar, $validator?)

Creates a new B<ABNF::Generator> object.

$grammar isa B<ABNF::Grammar>.

$validator isa B<ABNF::Validator>.

Children classes can get acces for them by $self->{_grammar} and $self->{_validator}

=cut

method new(ABNF::Grammar $grammar, ABNF::Validator $validator?) {
	my $class = ref($self) || $self;

	croak "Cant create instance of abstract class" if $class eq 'ABNF::Generator';

	$self = {
		_cache => {},
		_grammar => $grammar,
		_validator => $validator || ABNF::Validator->new($grammar)
	};

	bless($self, $class);

	$self->_init();

	return $self;
}

method _init() {
	$self->{handlers} = {
		Range => $self->can("_range"),
		String => $self->can("_string"),
		Literal => $self->can("_literal"),
		Repetition => $self->can("_repetition"),
		ProseValue => $self->can("_proseValue"),
		Reference => $self->can("_reference"),
		Group => $self->can("_group"),
		Choice => $self->can("_choice"),
		Rule => $self->can("_rule"),
	};
}

=pod

=head1 $generator->C<_range>($rule, $recursion)

Generates chain for range element.

Abstract method, most of all children must overload it.

$recursion is a structure to controle recursion depth.

=cut

method _range($rule, $recursion) {
	croak "Range handler is undefined yet";
}

=pod

=head1 $generator->C<_string>($rule, $recursion)

Generates chain for string element.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _string($rule, $recursion) {
	croak "String handler is undefined yet";
}

=pod

=head1 $generator->C<_literal>($rule, $recursion)

Generates chain for literal element.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _literal($rule, $recursion) {
	croak "Literal handler is undefined yet";
}

=pod

=head1 $generator->C<_repetition>($rule, $recursion)

Generates chain for repetition element.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _repetition($rule, $recursion) {
	croak "Repetition handler is undefined yet";
}

=pod

=head1 $generator->C<_reference>($rule, $recursion)

Generates chain for reference element.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _reference($rule, $recursion) {
	croak "Reference handler is undefined yet";
}

=pod

=head1 $generator->C<_group>($rule, $recursion)

Generates chain for group element.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _group($rule, $recursion) {
	croak "Group handler is undefined yet";
}

=pod

=head1 $generator->C<_choice>($rule, $recursion)

Generates chain for choce element.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _choice($rule, $recursion) {
	croak "Choice handler is undefined yet";
}

=pod

=head1 $generator->C<_rule>($rule, $recursion)

Generates chain for rule element, usually -- basic element in chain.

Abstract method, most of all children must overload it

$recursion is a structure to controle recursion depth.

=cut

method _rule($rule, $recursion) {
	croak "Rule handler is undefined yet";
}

=pod

=head1 $generator->C<_generateChain>($rule, $recursion)

Generates one chain per different rule in $rule.

$rule is structure that Return from B<ABNF::Grammar::rule> and like in B<Parse::ABNF>.

$rule might be a command name.

$recursion is a structure to controle recursion depth.

at init it have only one key -- level == 0.

You can create new object perl call or use one.

See use example in ABNF::Generator::Honest in method _choice

=cut

method _generateChain($rule, $recursion) {

	my @result = ();

	if ( ref($rule) ) {
		croak "Bad rule " . Dumper($rule) unless UNIVERSAL::isa($rule, "HASH");
	} elsif ( exists($BASIC_RULES->{$rule}) ) {
		$rule = $BASIC_RULES->{$rule};
	} else {
		$rule = $self->{_grammar}->rule($rule);
	}

	$self->{handlers}->{ $rule->{class} }
	or die "Unknown class " . $rule->{class};

	return $self->{handlers}->{ $rule->{class} }->($self, $rule, $recursion);
}

=pod

=head1 $generator->C<generate>($rule, $tail="")

Generates one sequence string for command $rule. 

Using cache $self->{_cache}->{$rule} for this rule, that speeds up this call.

$rule is a command name.

$tail is a string added to result if it absent.

dies if there is no command like $rule.

=cut

method generate(Str $rule, Str $tail="") {
	croak "Unexisted command" unless $self->{_grammar}->hasCommand($rule);

	$self->{_cache}->{$rule} ||= [];