From: Brian Candler <B.Candler@...>
Date: 2007-03-25T21:48:12+09:00
Subject: Re: pointer to function

On Sun, Mar 25, 2007 at 09:10:12PM +0900, ekkehard.horner wrote:
>     my %Fncs = (   'frsFnc' => [ 'just tell "frsFnc"', \&frsFnc ]
>                  , 'secFnc' => [ 'just tell "secFnc"', \&secFnc ]
>                );

You have several options, depending on how literally you want to translate
this.

# (1) this is a Method object which is bound to the current object. Use
#    fncs['frsFnc'][1].call(args...)
# to invoke it

fncs = {
   'frsFnc' => [ 'just tell "frsFnc"', method(:frsFnc) ],
}

# (2) this is a Symbol giving the *name* of a method. Use
#    some_object.send(:method, args...)
# to invoke it on an arbitary object (which could be 'self')

fncs = {
   'frsFnc' => [ 'just tell "frsFnc"', :frsFnc ],
}

# (Note: this means you may not need to build the fncs hash at all; just let
# the caller pass in a method name. This assumes you don't mind the caller
# being able to call *any* method on your object)

# (3) this is an anonymous function, like "sub { ... }" in Perl. Use
#   fncs['frsFnc'][1].call(args...)
# to invoke it.

fncs = {
   'frsFnc' => [ 'just tell "frsFnc"', proc { puts "hello" } ],
}

A fourth option is to put the callable methods in a Module. Use
Modname.instance_method(:method_name) to get an 'unbound method' object,
which is like a method but not bound to a specific object instance. You then
have to bind it to a particular object when you call it.

There are probably others :-)

HTH,

Brian.