From: GOTO Kentaro <gotoken@...>
Date: 2002-10-02T04:25:29+09:00
Subject: Re: thoughts on typelessness

At Wed, 2 Oct 2002 03:54:25 +0900,
Paul Brannan wrote:
> 
> On Wed, Oct 02, 2002 at 02:43:22AM +0900, GOTO Kentaro wrote:
> > Hmm, the name to_flt looks to be called by "%f" % obj.  How about
> > to_array, to_hash, to_integer and to_string for the name of default
> > dispatch of Array(), Hash(), Integer() and String() respectively?
> 
> A grep for to_flt in the Ruby source comes up empty.  Where are you
> seeing to_flt get called?

Sorry for my unclear English. 

to_str or to_ary are used as default implicit conversion method. 
For example, obj.to_str would be called by "%s" % obj.  

Then I thought that an implicit conversion should differ from strict
conversion.  I'd like to propose a new mechanism

  general purpose:      obj.to_a
  implicit conversion:  obj.to_ary    # called by *obj 
  strict conversion:    obj.to_array  # called by Array() 

In this mechanism, to_flt would be positioned at implicit conversion.
An implicit to_flt conversion MAY call to_f as its default definition.
And to_flt MAY also be distinct from to_float.  With this mechanism we
can customize them, e.g.,

  obj.to_f    #=> 1.23
  "%f" % obj  #=> "1.23" if obj.to_flt == 1.23
  Float(obj)  #=> raise an ArgumentError

Is it overkill?


-- Gotoken