Le 11 août 2014 à 21:30, Tab Atkins Jr. <jackalm...@gmail.com> a écrit :
>
> No, all of Peter's comprehensions are short and easy to comprehend.
> Comparing it with Dave's version, I think it's simply a matter of the JS
> comprehensions requiring more syntax, and crossing the line from "easy to
> read" to "hard to read". Here's the one bit in particular that stands out:
>
> Norvig:
> unitlist = ([cross(rows, c) for c in cols] +
> [cross(r, cols) for r in rows] +
> [cross(rs, cs) for rs in ('ABC','DEF','GHI') for cs in
> ('123','456','789')])
>
> Herman:
> var unitlist
> = [for (c of cols)
> cross(rows, [c])]
> .concat([for (r of rows)
> cross([r], cols)])
> .concat([for (rs of ["ABC","DEF","GHI"])
> for (cs of ["123","456","789"])
> cross(rs.split(""), cs.split(""))]);
>
> Norvig's is simple and easy to read. Herman's is polluted with additional
> method calls and more indentation. If we remove the indentation...
>
> var unitlist
> = [for (c of cols) cross(rows, [c])]
> .concat([for (r of rows) cross([r], cols)])
> .concat([for (rs of ["ABC","DEF","GHI"]) for (cs of ["123","456","789"])
> cross(rs.split(""), cs.split(""))]);
>
> Now pretend that for-of works on strings... (maybe it already does, for all I
> know, and Dave was just being paranoid)
>
> var unitlist
> = [for (c of cols) cross(rows, c)]
> .concat([for (r of rows) cross(r, cols)])
> .concat([for (rs of ["ABC","DEF","GHI"]) for (cs of ["123","456","789"])
> cross(rs, cs)]);
>
> Okay, it's still a little bit harder to read, due to the .concat() calls and
> their attendant additional parens, and the parens around the for-of bodies,
> but it's not *terribly* worse. It's still bad enough that I don't know if
> I'd write it.
I think I'd have written (without comprehension):
var unitlist = [...function*() {
for (let c of cols)
yield cross(rows, c)
for (let r of rows)
yield cross(r, cols)
for (let rs of ["ABC","DEF","GHI"])
for (let cs of ["123","456","789"])
yield cross(rs, cs)
}]
although it is somewhat lengthier because of extra `function*`, `let`s and
`yield`s.
—Claude
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