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Just as a note,

It seems to me that the grep example shouldn't be used anyway, because you're modifying $_ en passent. This can lead to all kinds of problems, not the least of which is a lower level programmer misunderstanding why this is bad.

Doing that in two lines seems to be a bit better, if more verbose:

s/foo/bar foreach @arr; return grep { /bar/ } @arr;

update: excuse my slow thinking

i first thought that clintp was demonstrating canonical use of grep, which is documented, but difficult to understand at first (akin to canonical use of map). i feel sheepish. It now behooves me to think that he was in fact directing his snippet at what i was trying to point out: a subtle feature that is documented and so able to be understood (and used in production code).

i feel there is still a point to be made however. While most of his other code snippets could be discovered plainly from documentation, this example is a bit more insidious. The student learning grep will probably not "get" what is being said in the documentation about this feature (i know i didn't the first few times through it). More to the point, while clintp's example is fine, a learning student would probably not notice the pitfall, since it doesn't directly follow; thinking they will is, sadly, overestimating their intelligence. Then later they could easily try altering $_ and get bizarre results.

In the end, it seems better to avoid this usage in code for maintainability, whereas the other examples seem perfectly valid. Maybe it's just me...

In reply to Re: Fear of Large Languages by jynx
in thread Would you use 'goto' here? by Ovid

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