jeffreykegler

perl bench.pl /usr/share/iso-codes/json/iso_639-3.json
Using /usr/share/iso-codes/json/iso_639-3.json
Using Marpa::R2 8
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
             s/iter ESLIF JSON  SLIF JSON   JSON::PP   JSON::XS
ESLIF JSON     7.43         --       -10%       -71%      -100%
SLIF JSON      6.68        11%         --       -68%      -100%
JSON::PP       2.13       249%       214%         --       -99%

jeffreykegler

make basic
perl bench.pl test.json
Using test.json
Using Marpa::R2 8
              Rate  SLIF JSON   JSON::PP ESLIF JSON   JSON::XS
SLIF JSON    107/s         --       -71%       -76%      -100%
JSON::PP     366/s       241%         --       -18%       -99%
ESLIF JSON   449/s       318%        23%         --       -99%
JSON::XS   38642/s     35944%     10465%      8514%         --

jeffreykegler

The post An Overview Of The Marpa Parser was originally published at https://lukasatkinson.de/2015/marpa-overview/.

---

Parsing pervades all of computing. Whenever we are dealing with some data format or a programming language, something needs to parse that. But writing a good grammar for a given language, and picking a suitable parser is not always easy.

For example, let's look at some strings in an example language:

jeffreykegler

#!perl
use strict;
use warnings;
use 5.010;
use Data::Dumper;
use Marpa::R2;

sub My_Actions::dwim {
    shift;
    return $_[0] if scalar @_ == 1;

jeffreykegler

#!perl
use strict;
use warnings;
use 5.010;
use Data::Dumper;
use Marpa::R2;

sub My_Actions::dwim {
    shift;
    return $_[0] if scalar @_ == 1;

jeffreykegler

#!perl
use strict;
use warnings;
use 5.010;
use Data::Dumper;
use Marpa::R2;

sub My_Actions::dwim {
    shift;
    return $_[0] if scalar @_ == 1;

jeffreykegler

#!perl
use strict;
use warnings;
use 5.010;
use Data::Dumper;
use Marpa::R2;

# This grammar tries to be equivalent to a PEG or Regex with ordered choice:
# List: Item*
# Item: VAR = VAR // VAR = // VAR

jeffreykegler

\datethis
@*Intro. This program generates clauses for the transition relation
from time $t$ to time $t+1$ in Conway's Game of Life, assuming that
all of the potentially live cells at time $t$ belong to a pattern
that's specified in |stdin|. The pattern is defined by one or more
lines representing rows of cells, where each line has `\..' in a
cell that's guaranteed to be dead at time~$t$, otherwise it has `\.*'.
The time is specified separately as a command-line parameter.

The Boolean variable for cell $(x,y)$ at time $t$ is named by its

jeffreykegler

#!/usr/bin/perl

use 5.010;
use strict;
use warnings;

use Data::Dumper;
use English qw( -no_match_vars );

use Test::More tests => 6;

jeffreykegler

DSL:
:default ::= action => [values] bless => ::lhs
lexeme default = action => [ start, length, value ]
    bless => ::name latm => 1

:start ::= Script
Script ::= Expression+ separator => comma
comma ~ [,]
Expression ::=
    Number bless => primary