That's a great response, thanks. Clears things up. One question, should be always be using _ for the invocant or should we try to restrict it?
On Wed, Sep 17, 2008 at 10:52 PM, Patrick R. Michaud <[EMAIL PROTECTED]>wrote: > On Wed, Sep 17, 2008 at 08:37:36PM +0800, Chris Davaz wrote: > > I am confused about how we should setup method signatures: > > > > Let's take a look at a line in any-str.pir: > > > > 46 .sub 'comb' :method :multi(_) > > 47 .param pmc regex > > 48 .param int count :optional > > 49 .param int has_count :opt_flag > > > > As you can see we have one parameter specified in :multi which is _ (any > > type). However we also have two .param lines, 47 and 48. So here are some > > questions: > > > > I noticed 'self' is implicitly defined, however does 'self' eat up a > > parameter? Should we always have one parameter in :multi specified for > the > > object the method is running on? > > Yes, the first argument of the :multi refers to the invocant. > > > Also, I played around with :multi by putting in different things. With > the > > above method here is what I tried and the result > > > > :multi(_) - works > > Restricts the sub to being invoked by callers supplying > at least one argument (in this case, the argument is the > invocant, since the sub is declared as :method). > > > :multi(_, _) works > > This says that the sub requires at least two arguments (of any > type). The first will go into 'self', the second into 'regex'. > > > :multi(_,_,_) doesn't work > > This says that the sub requires at least three arguments (of > any type). This doesn't really match the sub definition though, > which has an invocant, a required argument, and an optional argument. > > > :multi(_,Integer) doesn't work > > This says the invocant may be of any type, and the first argument > must be an Integer (or a subclass of Integer). Probably not what > we want given that the first parameter of the sub is 'regex'. > > > > :mult(Sub) doesn't work > > This says that the sub can be invoked only on Sub invocants. > > > Some clarification surrounding the use of :multi would help a lot. > > Hope the above helps. I don't know where :multi is documented in > Parrot itself; the pdd27 file doesn't provide much detail. > > Pm >
