Lukas Atkinson latk

MarpaX::Interface::Inline Specification

The MarpaX::Interface::Inline module provides the Inline Rule Interface (IRIF) to write grammars for the [Marpa parser generator][Marpa::R2]. While Marpa already provides the Scanless Interface (SLIF), the IRIF tries to provide a more productive frontend:

Longest-Acceptable-Token Matching: The builtin lexer is smart and only tries to find tokens that can actually be used at the current position. This makes it easier to nest languages.
Inline Rules and Quantifiers: A regex like syntax allows you to specify rules where you need them – and not every rule has to be named. Quantifiers include support for Perl6's separation operator %.
Inline Actions: Each production is associated with an action that builds the AST. With the IRIF, these are specified inline, directly after the rule which they operate on.

Certain languages like Python use leading indentation to denote blocks. Wouldn't it be nice if a Marpa frontend like the IRIF would have support for this? Well, the problem is that implementing the Off-side Rule is similarly difficult to implementing here-docs: both are non-context free constructs, but are easy to implement by maintaining state in the scanner.

Consider this piece of Python code:

def foo(x, y):
    return x + (2*
y)

foo(1, 2) #=&gt; 5

	#########################################
	# Solar Game #
	# #
	# (C) 2013 Donovan Roudabush #
	# GPU/Creative Commons #
	# #
	# [email protected] #
	# github.com/sharksfan98/solargame #
	#########################################

	use strict; use warnings; use 5.010;

	use Data::Dumper;

	my $data = <<'END';
	If ((Myvalue.xyz == 1) Or (Frmae_1.signal_1 == 1)) Then a = 1
	Else a = 0;
	END

	my $ast = Parser->parse(\$data);

	use strict; use warnings; use 5.010;
	use Data::Dumper;

	my $ast = bless( [
	[
	bless( [
	bless( [
	bless( [
	bless( ['Myvalue.xyz'], 'Ast::Var' ),
	'==',

	use strict; use warnings; use 5.010;

	my $ast = bless( [
	[
	bless( [
	bless( [
	bless( [
	bless( ['Myvalue.xyz'], 'Ast::Var' ),
	'==',
	bless( ['1'], 'Ast::Literal' )

	use strict; use warnings; use 5.010;

	my $ast = bless( [
	[
	bless( [
	bless( [
	bless( [
	bless( ['Myvalue.xyz'], 'Ast::Var' ),
	'==',
	bless( ['1'], 'Ast::Literal' )

	use 5.018; use strict; use warnings; use Benchmark ':all';

	cmpthese $ARGV[0] => {
	grep => \&with_grep,
	grep_light => \&with_grep_light,
	splice => \&with_splice,
	slice => \&with_slice,
	copy => \&with_copy,
	};

	use strict; use warnings;
	use feature 'say';
	use autodie;

	use File::Slurp;
	use Mojo;
	use List::MoreUtils 'uniq';
	use Data::Dump qw/dd pp/;

	my %urls = (

	package GetoptSubset;
	# Copyright 2017 Lukas Atkinson
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software