Re^5: pack and unpack multiple arrays with one common repeat prefix

G'day hexcoder,

Perhaps, instead of a table of just templates, you could use a table of coderefs whose functionality includes preprocessing, unpacking, formatting, and anything else you need.

Here's a highly contrived and primitive example just to show the technique.

#!/usr/bin/env perl -l

use strict;
use warnings;

my %decode_type = (
    A => sub { "Do TypeA stuff with '$_[0]'" },
    B => sub { "Do TypeB stuff with '$_[0]'" },
);

while (<DATA>) {
    chomp;
    my ($type, $msg) = split /\s+/, $_, 2;
    my $decoded = $decode_type{$type}->($msg);
    print $decoded;
}

__DATA__
B message B1
A more complex message A1
B message B2
[download]

Output:

Do TypeB stuff with 'message B1'
Do TypeA stuff with 'more complex message A1'
Do TypeB stuff with 'message B2'
[download]

I don't know how useful that might be; however, your general description suggested this approach.

— Ken

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Re^6: pack and unpack multiple arrays with one common repeat prefix by hexcoder (Curate) on Jun 16, 2017 at 07:29 UTC
The idea/goal was to seperate the decoding engine (code) from the data structure descriptions (templates) in order to decrease (inter)dependencies reduce code by avoiding (slightly different) duplicates for different structures So, I see your approach as the next best method, when I fail to express the structures with templates in a table. Using a table with handler functions is certainly the most flexible way allowing for very special decoding tasks. Thanks, hexcoder	[reply]
Re^7: pack and unpack multiple arrays with one common repeat prefix by kcott (Archbishop) on Jun 17, 2017 at 06:45 UTC
I'm glad to see that had, at least some, appeal. It was, as stated, somewhat "primitive". Expanding upon that a little, the following is more generally what I had in mind, which removes duplicate code and separates the "decoding engine (code)" (putting it into `Decoupled.pm`). The expanded script (note there's no change to the original `while` loop or input data): `#!/usr/bin/env perl -l use strict; use warnings; use lib '.'; use Decoupled qw{ preprocess_complex_message handle_generic_message }; my %decode_type = ( A => sub { handle_generic_message( A => preprocess_complex_message($_[0]) ) }, B => sub { handle_generic_message(B => $_[0]) }, ); while (<DATA>) { chomp; my ($type, $msg) = split /\s+/, $_, 2; my $decoded = $decode_type{$type}->($msg); print $decoded; } __DATA__ B message B1 A more complex message A1 B message B2` [download] The `Decoupled` module: `package Decoupled; use strict; use warnings; use Exporter 'import'; our @EXPORT_OK = qw{ preprocess_complex_message handle_generic_message }; sub preprocess_complex_message { $_[0] =~ /more complex (.*)/; $1 } sub handle_generic_message { sprintf "Do Type%s stuff with '%s'", @_ } 1;` [download] The new output: `Do TypeB stuff with 'message B1' Do TypeA stuff with 'message A1' Do TypeB stuff with 'message B2'` [download] — Ken	[reply] [d/l] [select]