From: Christoph <swap@...> (news_chr)
Date: 2003-10-05T10:56:59+09:00
Subject: Re: Python syntax in Lisp and Scheme

"Grzegorz Chrupa�,a" wrote:
....
>
> I don't really feel quite qualified discuss Ruby's design decisions wrt
the
> relation between methods, procedures and objects, but I don't think the
> split between methods and objects is as deep as you claim:

There is a huge difference between ``garden variety''  Ruby functions,
usually called methods, ala

    def foo() end

and Method objects like

    meth = "meth".method(:foo)

The former really ``live'' outside of Ruby's object space, the latter are
concrete living breathing objects  - i.e. instances of the Method class.


---
def enumerate_method_objects
  cnt = ObjectSpace.each_object(Method) {|mth|
    p mth
  }
  puts "There are #{cnt} Method objects\n\n"
end

class String
  def foo
    self + " hello"
  end
end


##
ary = [1,2]
ruby = "Ruby"

enumerate_method_objects() # no Method object exists

## create two Method objects
ary_length =  ary.method(:length)
ruby_foo   = ruby.method(:foo)

enumerate_method_objects() # 2 Method object exists

## manipulate the objects ``ary'' and ``ruby'' a bit
p ary  << 3            #  [1, 2, 3]
p ruby << " says"  #  "Ruby says"

## use the method objects
p ary_length[]       # 3
p ruby_foo[]         # "Ruby says hello"

## which is pretty much the same as writing

p ary.length()       # 3
p ruby.foo()         # "Ruby says hello"

---

resulting

---
There are 0 Method objects

#<Method: String#foo>
#<Method: Array#length>
There are 2 Method objects

[1, 2, 3]
"Ruby says"
3
"Ruby says hello"
3
"Ruby says hello"
---


> I do tend to think that Ruby would be better off with a more unified
> treatment of blocks, procedures and methods, but my understanding of the
> issues involved is very incomplete. Perhaps Smalltalk experts would be
more
> qualified to comment on this.


By not elevating function (methods) into real objects, you pretty much
avoided the problem of users complaining about the lack of  higher order
function objects:-)


/Christoph