🚀 go-pugleaf

In message <4h5j7b$1ur@bcarh8ab.bnr.ca> - "ian (i.) willmott" 
<willmott@bnr.ca> writes:

:>The original article (this has expired on my site and possibly others
:>as well; maybe I should repost it) suggests a new type
:>"pointer-to-bound-member-function" which would encapsulate an object
:>pointer and a pointer to a member function of that class.

Having previously considered the suggestion you proposed and forced to solve 
the problem in current language, and with a lot of experience using a
current-language solution, I feel it is actually preferable to the extension 
you propose in the following areas:

A)It is more type-flexible. By that I mean it is possible to produce a 
callback system that is type-safe, yet tolerant of type differences in the 
caller/callee signatures that are either implicitly convertible or can be 
ignored. For example if the caller requires a function to which it can pass 
an int and from which it expects nothing, using my library it is possible to 
bind the callback to a function that takes an int and returns an int (return 
value is ignored), or takes a long and returns void (compiler implicitly 
converts int->long). Once you get involved with polymorphism this becomes 
critical: caller passes ptr-to-derived, callee accepts ptr-to-base. Any 
language extension approach would have the rigidity normally associated with 
pointers-to-functions, i.e. exactly matching signatures required. 

B)It is easier to extend; to things like callbacks with stored arguments 
etc.

Rich
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