Re(3): do/redo or for(;;): what's Kosher?

Just curious. Why would you prefer this:

{
   # do stuff
   last if BREAK-CONDITION;
   redo;
}
[download]

to this:

{
   # do stuff
   redo if !BREAK-CONDITION;
}
[download]

or even (just to be pedantic),

{
   # do stuff
   redo unless BREAK-CONDITION;
}
[download]

dmm

Comment on Re(3): do/redo or for(;;): what's Kosher? Select or Download Code

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(tye)Re3: do/redo or for(;;): what's Kosher? by tye (Sage) on Jan 05, 2002 at 05:38 UTC
I'm pretty sure that the reason is: `{ # do loop stuff to be done at least once last if BREAK-CONDITION; # do middle loop stuff <<< This part was left out redo; }` [download] which I'd still use `while(1)` for. Plus it allows you to do: `{ # read next line last if NoMoreLines # extract item from line redo if NoItemInLine last if EndOfItemListFound # categorize item redo if WrongItemCategory # check for updates redo if NoUpdatesThisCategory; # check permissions last if NoUpdatesAllowed; redo if ThisUpdateNotAllowed; # do update redo if NotFatal; # handle fatal error # (note, no "redo" here so this part isn't really # part of the "loop", just stuff to do once unless # "last" gets triggered above.) } # done with items` [download] where it is very easy to throw in a new check or new code in. But, as I said elsewhere, I find that power to be too easy to abuse. YMMV. - tye (but my friends call me "Tye")	[reply] [d/l] [select]
Re(tye 2): do/redo or for(;;): what's Kosher? by dmmiller2k (Chaplain) on Jan 06, 2002 at 08:34 UTC
Ah, in that context, I see where this approach could be useful. I think I agree with you, though, that the `while (1)` (with scattered `next`s in place of `redo`s) accomplishes the same thing in a more self-explanatory way. dmm You can give a man a fish and feed him for a day ... Or, you can teach him to fish and feed him for a lifetime	[reply] [d/l] [select]


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