Re^3: Yet Another Rosetta Code Problem (Perl, Ruby, Python, Haskell, ...) (js)

[tye]

in reply to Re^2: Yet Another Rosetta Code Problem (Perl, Ruby, Python, Haskell, ...)
in thread Yet Another Rosetta Code Problem (Perl, Ruby, Python, Haskell, ...)

I couldn't get that javascript version to work. Sure, it looks nice. It looks very much like something many tried as a first stab in Perl. But I'm not convinced it works in javascript any better than it works in Perl. I was not able to get it to return anything (while in Perl it returns too much).

Update: Thanks, eB. I was eventually able to get your example to demonstrate that the code works.

[erroneousBollock]

It works just fine. Try pasting the following into your url bar:

   javascript:alert("ZBBBCZZ".match(/((.)\2*)/g))

That should alert the output of .toString() called on the array result.
If you have Firefox use the following to see the unadulterated array source:

   javascript:alert(("ZBBBCZZ".match(/((.)\2*)/g)).toSource())

-David

Update: Does that imply that Javascript has different capture semantics than perl?

[tye]

Does that imply that Javascript has different capture semantics than perl?

No. It is just that match() returns the matched substrings, not the captured substrings. If //g in a list context could be told to return the matched substrings (what it does when there are no capturing parens), then the same solution would work in Perl.

A better JavaScript solution is actually: "ZBBBCZZ".match(/(.)\1*/g). No need for the second set of parens.

[pKai]

Telling m//g in list context to forget about the captures and just return the matches:

@list = "ZBBCZZ" =~ /(??{'(.)\1*'})/g;

or probably more exact: there are no captures m// can see