Re: Re: GOTO considered (a necessary) evil?

But a redo (just like next and last is just a glorified goto.

I consider this statement blatently false and missleading.

goto FOO ~~causes~~ is designed to cause execution to jump to the lable FOO anywhere in your script (provided no initialization would be neccessary to get there)
redo FOO ~~will only work if the~~ is designed to cause execution to jump to label FOO if it exists at some surrounding loop block. (allthough it will work w/warning if the label applies to some dynamicly surrounding loop)

This typo generates an error...

perl -le 'BAR: print 1; BAZ: for (2..3) {print; redo BAR; }'
[download]

This typo causes an infinite loop...

perl -le 'BAR: print 1; BAZ: for (2..3) {print; goto BAR; }'
[download]

(Updated to be less pedantic... the point is, goto is for arbitrary jumping, redo is for controlled jumping to the begining of a loop. Could you live w/o redo if you had goto? yes. Does that mean you should just use goto and not bother with redo? no.)

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Re: Re: Re: GOTO considered (a necessary) evil? by clintp (Curate) on Jul 16, 2002 at 02:19 UTC
But a redo (just like next and last is just a glorified goto. I consider this statement blatently false and missleading. redo FOO will only work if the label FOO exists at some surrounding loop block I consider this statement to be inaccurate and not quite pendantic enough for flaming someone! Observe: `sub bar { no warnings 'exiting'; redo FOO; } FOO: { print "Hey!"; bar(); }` [download] The redo worked and the label did not exist in a surrounding loop block.	[reply] [d/l]
Re: GOTO considered (a necessary) evil? by Abigail-II (Bishop) on Jul 16, 2002 at 09:25 UTC
This typo generates an error... `perl -le 'BAR: print 1; BAZ: for (2..3) {print; redo BAR; }'` [download] This typo causes an infinite loop... `perl -le 'BAR: print 1; BAZ: for (2..3) {print; goto BAR; }'` [download] That's a pretty weak example, because if you omit the typos, both `perl -le 'BAR: print 1; BAZ: for (2..3) {print; redo BAZ; }'` [download] and `perl -le 'BAR: print 1; BAZ: for (2..3) {print; goto BAZ; }'` [download] behave identically - looping infinitely. Abigail	[reply] [d/l] [select]