[erlang-questions] Use of logical "not" in `case`

[zxq9@REDACTED]

On 2018年2月12日月曜日 0時48分56秒 JST Richard O'Keefe wrote:
> (a) I don't care whether false precedes true or true precedes false.
> (b) I *definitely* get confused by 'not'.  Human beings in general
>     are stunningly bad with 'not'.  Empirical studies have shown
>     that programmers are not good with it either.
> (c) I have learned to be wary of 'boolean'.  Long experience teaches
>     me that either there are more than 2 possibilities, or that there
>     is more to say one at least one case, and often both.  Here I
>     would erase from my memory all trivial fond memories of maps:is_key/2
>     and write
>         case maps:find(Thingy, Map)
>           of {ok, _Old_Value} -> ...
>            ; error            -> ...
>         end
>     so that there was no doubt about which branch was which.
>     Seriously: your grandfather had to use IF and COND a lot when he
>     wrote Lisp, but *we* have pattern matching.
> (d) In fact, we really do have pattern matching, so here
>         case Map
>           of #{Thingy := _} -> ...
>            ; _              -> ...
>         end
>     perfectly expresses our intent.


Indeed! The sentiment seems universal.

Thanks to everyone who took the time to explain their opinion on it.
Eventually I'll probably compile a style guide from the various cases
of "is this annoying or not" sort of style questions I've asked here
over the last several years.

Eventually.

- Craig