in reply to "if" Considered Harmful in OO programming

Interesting post.

Any time I see something like 

if ( $x and !$y ) {
  .. # true, false
} elsif ( !$x and $y ) {
  .. # false, true
} else {
  .. # true, true or false, false
}

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warning bells go off because I wonder if it could have been written as 
if ( $x ) {
  if ( $y ) {
    .. # true, true
  } else {
    .. # true, false
  }
} else {
  if ( $y ) {
    .. # false, true
  } else {
    .. # false, false
  }
}

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instead. Granted, this may not be required much of the time, but it sure makes code maintenance a year later a little easier.

Alex / talexb / Toronto

"Groklaw is the open-source mentality applied to legal research" ~ Linus Torvalds

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Re^2: "if" Considered Harmful in OO programming
by ikegami (Patriarch) on Sep 21, 2004 at 23:31 UTC

    I disagree. I don't think duplicating code is good for maintenance at all.

    What if you have 3 values instead of 2. Your if would be three levels deep, and have say 5 identical pieces of code. Let's hope you don't forget to change all 5 if a changes is needed. What you suggest is not scaleable at all.

    else means all other cases. If you have 2 values in a flat if, else covers the differences of 4 cases. If you have 3 variables in a flat if, else covers the differences of 9 cases. etc. It's not that hard to process, especially compared to what you recommend.

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