UPDATE: I got my example to work with the following code: 

say unpack '(C.*/X/xa@1)3', "\003\003\003abcdef"; # prints 'aaa'
say unpack '(C.*/X/xa@1)3', "\005\004\003abcdef"; # prints 'cba'

[download]
Thank you Loops and 7stud for your help.



Good morning! I am trying to get a better understanding of Perl's pack/unpack function.

I have a pretty good grasp of the "standard" templates, but I simply cannot get my head around the "@" and "." templates.

Does anyone know of (or have) any tutorials/examples that delve more in depth with the "@" and "." templates? perldoc pack and perlpacktut have the briefest mention of "@" and (to my eyes) no mention of ".".

A more concrete example: After playing around with pack and the "/" modifier, I came up with the following: 

say unpack '(C/xa@)3', "\003\003\003abcdef"; # prints 'bcd'
say unpack '(C/xa@)3', "\005\004\003abcdef"; # prints 'ddd'

[download]
1. I understand what C/xa is doing, but what does @ do in this case?

2. How would I make the template skip from the absolute start of the string, rather than from a relative position?
e.g.: 

say unpack '(C/xa@)3', "\003\003\003abcdef"; # prints 'bcd' - would li
+ke 'aaa'
say unpack '(C/xa@)3', "\005\004\003abcdef"; # prints 'ddd' - would li
+ke 'cba'

[download]

Thank you for your time.

In reply to [SOLVED] Pack/unpack - understanding the '@' and '.' templactes by ateague

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