Parsing binary structure with Perl6 Grammar

Question

What is the best option to parse a binary structure with Perl6 .

in Perl5 we have the pack/unpack methods on Perl6 they seems experimental

is it possible to use Perl6 grammar to parse binary data let's say i have a file which have records on the following binary format :

struct record {
short int ut_type;

char ut_line[UT_LINESIZE];
char ut_id[4];
char ut_user[UT_NAMESIZE];
char ut_host[UT_HOSTSIZE];


}

is it possible to parse this file with Perl6 grammar ?

Answer 1

What is the best option to parse a binary structure with Perl6?

Especially given that you know about P5's pack/unpack, the new P5pack module is plausibly the appropriate solution. (I haven't tested it. It's new. Aiui it doesn't implement everything and it doesn't mimic P5's pack slavishly. But it's Liz.)

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If the new pure P6 implementation of P5's pack interface linked above does not do what you need done, another obvious solution is using the original P5 functions, executed by a regular perl 5 binary, in your P6 code. The following is incomplete / untested but I mean something roughly like:

use Inline::Perl5 ; my \P5 = Inline::Perl5.new ;

my $mem = Buf ... ;

my $hex = P5.call('unpack', 'H*', $mem) ;

(Or, conversely, write the mainline as P5 code, adding P6 code via Inline::Perl6.)

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In the current version of P6, which is 6.c, grammars can only process text.

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2 years ago P6er "skids" wrote:

"There are enough people wanting binary grammars that I think it will come to be" (written in 2016).

At that time they also put together the following related links:

• skid's then new idea for a packing foo { template bar { ... } } construct plus their much older "very old, low level types thoughts".

• ShimmerFairy's "thoughts on possible binary grammars in P6 (incomplete)"

• Juerd's "RFC: A more Perl6-esque "unpack"".

• smls's "Binary Parsing in Perl 6".

• masak's "A first approach to pack/unpack in Perl 6".

• jnthn's "talk on Grammar::Generative" (video).