[erlang-questions] erlang-questions Digest, Vol 24, Issue 11
Mon May 4 17:00:34 CEST 2009
> My $0.02 is that this advice is, and always has been, hogwash. It is
>> a rare function that can return several valid answers. So, the
>> default should be to return a valid answer, i.e. one that can be
>> used directly, or throw an error.
>> My theory is that the people who wrote this "programming rule" were
>> (good) C programmers, and thus felt a need to check if the value
>> returned was ok before they dared use it.
> Your theory is incorrect. The reason keysearch returns tagged result
> values is that the thing you're searching for might have a value of false.
> Tagged results are the only way to return a value such that any value is
> legal; otherwise you need a placeholder value for "nothing found", which is
> not a tolerable admission in basic datastructure behavior. There is no way
> to guarantee that every legal value in a datastructure can be unambiguously
> fetched without tagging.
> Manual advice is correct. It's generally a bad idea to call the advice in
> the manual hogwash when you're still guessing about the reason it was
> there. This is honestly pretty 101.
Aaaaaaaaaaaand then I drink more coffee, realize that it returns the
complete tuple rather than the field, that I'm thinking of proplists and
that I've made a jackass of myself. Lovely morning for some dumb, don't you
I retract this.
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