Beefy Boxes and Bandwidth Generously Provided by pair Networks
We don't bite newbies here... much

comment on

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

I have a few comments and I'll just leave them here in no particular order:

  1. I wish you would have defined "word" prior to using it willy-nilly. It's jargon that your tutorial's audience it's likely to be familiar with. From WordNet: a word is a string of bits stored in computer memory; "large computers use words up to 64 bits long".

  2. Bytes are almost always eight bits though that's not a universal constant. Perhaps it's infrequent enough that I didn't even need to mention but this one always gets my goat.

  3. Your use of "most" and "least" significant byte was also jargon. If you assume the value 0x12345678 then the most significant byte has the value 0x12 and the least significant has the value 0x78. From there the point on differently endian machines is just which order you start with when transcribing bytes.

  4. Your use of memory addresses is obfuscatory. This is better written as "Byte 0, byte 1, byte 2, byte 3". The only point at which a perl programmer cares about memory addresses is when doing non-perl programming or with the 'p' or 'P' format options. The point here is to indicate an order to the bytes in memory - that byte 0 might be located at a memory address 1000 is entire beside the point.

  5. White space is allowed without consequence in an unpack/pack format. It's just ignored except when it's a fatal error. I haven't nailed it down but some uses of whitespace just don't parse. That may be a bug but it's worth noting. This just means that in general people should use whitespace in a format to enhance readability - it doesn't affect it's operation.

  6. I've never been clear on the bit order within a byte - can you expand on that? I used to think that the differently endian machines also shuffled the bit order around as well. At this point I'm just confused.

In reply to Re: Pack/Unpack Tutorial (aka How the System Stores Data) by diotalevi
in thread Pack/Unpack Tutorial (aka How the System Stores Data) by pfaut

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

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?

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

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (6)
As of 2023-03-28 14:48 GMT
Find Nodes?
    Voting Booth?
    Which type of climate do you prefer to live in?

    Results (67 votes). Check out past polls.