Mon, 17 Mar 2014 23:02:52 +0100 от Panicz Maciej Godek
<[email protected]>:
>I think that there's a nice tradition among the Scheme programmers to
>use the name "compose" to refer to a composition function. It is much
>more descriptive than "dollar-asterisk" ("multiply dollars"? "a
>millionare marries a star"? "jackpot"?), and hence more
>reader-friendly, and unless you are doing some domain-specific
>research, your programs usually won't get much longer because of that.
Yes (and I did so, too, at start), but `compose' is too long a word (compare it
to Haskell's `.'). So I've decided to name procedure constructors in a unified
manner:
1) their names should start in the same distinguishing character;
2) and they should be short, and, probably, operator-like.
`$' is not popular in the Report, so it was chosen to not clash with standard
procedures.
Now, `*' seemed good for the compositions, because composition is a monoid
operation for functions.
Likewise `$0' is a procedure that returns constant-returning function (that is,
($0 1 2 3) always returns (values 1 2 3), whenever called with any set of
arguments), it is not something that costs zero dollars.
Once again: it was all for brevity.
Btw, how is "compose" defined traditionally?
>
>As to the behaviour of "filter", it is not clear whether it should
>behave as you described when more than one list is provided. Perhaps
>it should rather iterate over their cartesian product? Or concatenate
>the lists? That's one more thing to remember, and eventually one more
>thing to forget. If you're doing something complex, don't let your
>code pretend that it's something simple. So that's a rule: when (filter) is
>fed with one list, it returns one list. When it's fed with several lists, it
>returns as many lists.
This is just another feature of Scheme utilized to make a procedure more
general case.
С уважением,
[email protected]
В ходе опроса отдельно фиксировалось название оператора мобильной связи,
который был упомянут
первым – это позволило получить показатель приоритетной (top of mind)
спонтанной известности. Позиции
операторов «большой тройки» по параметру «первое упоминание» примерно очень
близки. Закономерно,
что чаще всего респонденты первым называли «своего» основного оператора
(72-82%).
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