Re: rethinking method calls with __mcall metamethod rather than __index/__call

[steve donovan <steve.j.donovan@...>]

On Sat, Jun 13, 2009 at 10:25 PM, David Manura<dm.lua@math2.org> wrote:
> As seen, if a set "s" has a method "union", this implies that
> s['union'] is true.  For such reason, Penlight [1] avoids using the
> index operator for membership tests in its set and map ADTs.

Yes, but I had been cheerfully assuming that m[key] would return the
goods reliably - this is indeed a Big Problem.  It's very natural that
set or map access is through [], but until we can control that
operation more fully, false matches are going to happen, in a nasty
silent way.  And hence explicit set() & get() methods.

People from a C++ background assume that [] is overrideable, but it
ain't an operator!

steve d.