sure you know everything as soon as you read `of` ... right ? How objectives are your points ? If you know JS that while looks very simple, IMO
On Tue, Aug 27, 2013 at 5:24 AM, Claude Pache <[email protected]>wrote: > > Le 27 août 2013 à 01:23, Brendan Eich <[email protected]> a écrit : > > > Andrea Giammarchi wrote: > >> Is it very useful because you wrote for instead of while ? > >> > >> ```javascript > >> while (m = re.exec(str)) > >> console.log(m[0]) > >> ; > >> ``` > > > > It is, for two reasons: > > > > 1. in JS only for can have a let or var binding in the head. > > > > 2. the utility extends to all for-of variations: array comprehensions, > generator expresisons. > > > > /be > > There is a third reason. The syntax: > > ```javascript > for (let m of re.execAll(str) { > // ... > } > ``` > > has the clear advantage to express the intention of the programmer, and > *nothing more*. It does not require good knowledge of the details of the > language to understand what happens. > > Indeed, when I read `while(m = re.exec(str))`, I really have to analyse > the following *additional* points: > * `=` is not a typo for `==` (here, some annotation would be useful); > * `RegExp#exec` returns a falsy value if *and only if* there is no more > match; > * `re` has its global flag set, and its `.lastIndex` property has not been > disturbed. > > All these tricks are unrelated to the intention of the programmer, and are > just distracting points, especially for any reader that use only > occasionally `RegExp#exec` with the global flag set. > > In summary, citing [1]: "Don’t be clever, don’t make me think." > > —Claude > > [1] http://www.2ality.com/2013/07/meta-style-guide.html > > >
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