On Tue, Jun 02, 2020 at 08:52:37AM +0300, Peter Pentchev wrote: > On Mon, Jun 01, 2020 at 01:36:19PM -0700, ToddAndMargo via perl6-users wrote: [snip] > > A follow up question: > > > > Is there a booboo in the documentation here? > > > > https://docs.raku.org/routine/starts-with > > multi method starts-with(Str:D: Str(Cool) $needle, :i(:$ignorecase), > > :m(:$ignoremark) --> Bool:D) > > > > It says "multi method" but only shows one method. > > Did they leave something out? > > Mmm, and this is where we come to the original error message :) > It says that there is a "starts-with()" method in the Str class that > accepts a "$needle" parameter of the Str:D type, but then (or, rather, > before that) it says that there is a "starts-with()" method in the Cool > class that accepts a "$neddle" parameter of the Cool:D type. Since Str > is derived from Cool, when you call a method on Str Raku will also look > for this method in Cool. Since the two methods accept parameters of > different types, they (or at least the method in the child class Str) > have to be declared as multi methods so Raku knows that a type mismatch > on the first one that it found does not mean that it should stop > looking. > > But, hm, why the documentation of the starts-with() method on the page > that you linked to does not mention that it is also present in Cool is > indeed an interesting question. Moreover, even the list of methods at > https://docs.raku.org/routine-method.html says "method starts-with() > from Str", while other methods such as subst() are listed as "from Cool, > Str", etc. I honestly don't know what the difference is, I expect it is > because of some internal details of the implementation of the Str > method, but I won't be able to look it in the source right now. Maybe > somebody else could shed some light on that?
OK, so I have a theory. Is it possible that this is because Str.starts-with() has a coercion of its $needle parameter from Cool, so whatever is building the documentation deduces (correctly) that Cool.starts-with() will never be invoked on anything that is Str or is derived from Str? Still, should the documentation not, well, document that any class derived from Cool has a starts-with() method? G'luck, Peter -- Peter Pentchev r...@ringlet.net r...@debian.org p...@storpool.com PGP key: http://people.FreeBSD.org/~roam/roam.key.asc Key fingerprint 2EE7 A7A5 17FC 124C F115 C354 651E EFB0 2527 DF13
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