Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

update: :) good night

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

Looks like a typo to me :)

http://perldoc.perl.org/perlpacktut.html#The-Alignment-Pit gives the use-case for this one, like a lot of these, its weird :)

Here is what I think I kinda know, remove the @ and you get

'x' outside of string in unpack

So I think @ means start from 0 , where 0 is the beginning for the innermost group (), instead of outside the end of the string :)

So C/x says read one byte/octet, then SKIP(x) that amount of bytes, so it eats the first \003, skips next 3 bytes , which are \003\003a

And its a group, so repeats that three times, each time the C/ eating up one byte, so it inches forward

Yeah, I don't think you can do this in one step, I think it's a 2 step operation like shown in the alignment pit

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

Wait a minute, doesn't this mean you understand 1.?

I think you can't do that, now the original makes even less sense to me

Ok, here's the 2step

use 5.12.0; my $raw = "\003\003\003abcdef"; my @offsets = unpack '(C)3', $raw; my $chucks = join ' ', map { '@' . $_ . 'a' } @offsets; say $chucks; say for unpack $chucks, $raw; use 5.12.0; my $raw = "\003\003\003abcdef"; my @offsets = unpack '(C)3', $raw; my $chucks = join ' ', map { '@' . $_ . 'a' } @offsets; say $chucks; say for unpack $chucks, $raw; __END__ @3a @3a @3a a a a

update: HAHAHAHAHAHAAH I DID IT  (C/x! a@)3 gets you aaa, not sure how that works, makes no sense to me, but its straight from gappy alignment pit portion

This is what I don't like about pack/unpack,


In reply to Re: Pack/unpack - understanding the '@' and '.' templates by Anonymous Monk
in thread [SOLVED] Pack/unpack - understanding the '@' and '.' templactes by ateague

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others meditating upon the Monastery: (4)
    As of 2015-07-30 03:26 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (269 votes), past polls