Beefy Boxes and Bandwidth Generously Provided by pair Networks
No such thing as a small change
 
PerlMonks  

Comment on

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

Well, what I mean is that I dont see how in C the conditional is only evaluated once. I dont know enough about how C implements a case statement to say for sure But i dont see how a case statement could be implemented in such a way without adding a lot of code to the statement, which would potentially be far more expensive than converting it to a series of conditionals. For instance something like this

switch (val) { case 1 : handle_case1; break; case 2 : handle_case2; break; case 5 : handle_case5; case 10: handle_case10; default: handle_default; }

I would guess would get converted to something like

if (val == 1) { handle_case1; } elsif (val == 2) { handle_case2; } else { if (val == 5) { goto CASE5; } elsif (val == 10) { goto CASE10; } else { goto DEFAULT; } CASE5: handle_case5; CASE10: handle_case10; DEFAULT: handle_default; }

Or something like it. I just dont see how it could be handled otherwise. Perhaps the fact that it only operates on ints means that there is a neater optimisation. But if you extend switch to handle strings as it does in pascal then I think the situation becomes even more difficult.

Thanks to the CB for clarifying that switch only handles ints. That issue may make my ruminations on this invalid. I dont know. Id be interested to hear from someone that does. As I said, this issue confuses me. :-)


---
demerphq

    First they ignore you, then they laugh at you, then they fight you, then you win.
    -- Gandhi



In reply to Re: Re: Re: Re: Perl Idioms Explained: && and || "Short Circuit" operators by demerphq
in thread Perl Idioms Explained - && and || "Short Circuit" operators by davido

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
  • Outside of code tags, you may need to use entities for some characters:
            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 drinking their drinks and smoking their pipes about the Monastery: (4)
    As of 2014-09-02 07:23 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      My favorite cookbook is:










      Results (20 votes), past polls