From: "ekkehard.horner" <ekkehard.horner@...>
Date: 2007-03-25T21:10:12+09:00
Subject: pointer to function

Just starting to learn Ruby, I'd like to ask if somebody would be so
kind as to help me 'translate' this Perl proof of concept code:

     package cApp;
     # POC application class that can run named Fncs via 'pointer to function'

     my %Fncs = (   'frsFnc' => [ 'just tell "frsFnc"', \&frsFnc ]
                  , 'secFnc' => [ 'just tell "secFnc"', \&secFnc ]
                );

     sub new
     { my $class = shift;

       my $self  = {   name => shift
                     , Fncs => \%Fncs
                   };
       bless( $self, $class );
     }

     sub run
     { my $self = shift;
       my $sFnc = shift;
       if( exists( $self->{ Fncs }->{ $sFnc } ) )
         { &{$self->{ Fncs }->{ $sFnc }->[ 1 ]}( $self )
         }
       else
         { print "no '$sFnc' in: ", join( ' ', keys( %{$self->{ Fncs }} ) ), "\n";
         }
     }

     sub frsFnc
     { my $self = shift;
       print $self->{ name }, '::frsFnc', "\n";
     }

     sub secFnc
     { my $self = shift;
       print $self->{ name }, '::secFnc', "\n";
     }

     package main;
     # main: create instance of cApp, get Fnc name, run named Fnc

     my $oApp = cApp->new( 'trivial' );
     my $sFnc = $ARGV[ 0 ] || 'frsFnc';
     $oApp->run( $sFnc );

to Ruby. That's what I have now:

     class CAPP

       @name = 'anonym'
       @Fncs = nil

       def to_s
         'POC application class that can run named Fncs via "pointer to function"'
       end

       def initialize( name )
         @name = name
         @Fncs = { 'frsFnc' => [ 'just tell "frsFnc"', nil ] ,
                   'secFnc' => [ 'just tell "secFnc"', nil ]
                 }
       end

       def run( sFnc )
         puts @name + '::run( "' + sFnc + '" )'
         if @Fncs.has_key?( sFnc )
            puts "can't call fnc by name yet"
         else
            puts 'no ' + sFnc + ' in: ' + @Fncs.keys.join( ' ' )
         end
       end

       def frsFnc
         puts @name + '::frsFnc'
       end

       def secFnc
         puts @name + '::secFnc'
       end

     end # class CAPP

     # main: create instance of cApp, get Fnc name, run named Fnc

     oApp = CAPP.new( 'trivial' )
     puts oApp.to_s

     puts "That's easy:"
     oApp.frsFnc()
     oApp.secFnc()

     sFnc = ARGV[ 0 ] || 'frsFnc'
     puts "Now call " + sFnc + ', please:'

     oApp.run( sFnc )

Is it possible to replace the "nil" in @Fncs and the
   puts "can't call fnc by name yet"
in run() with suitable Ruby expressions/statements?

I looked at lamba, but I don't want to define the functions using
strings.

Thanks