From: Chad Fowler <chad@...>
Date: 2003-11-28T13:38:13+09:00
Subject: Re: pre/post question/idea

On Fri, 28 Nov 2003, Joey Gibson wrote:

# 
# I much prefer the foo:pre, foo:post way to this. Of course the first 
# time I saw this (apart from doing AspectJ work in Java) was in Lisp, and 
# what Matz proposed was lifted straight from Lisp. Using 'pre' and 'post' 
# as equivalents of 'def' seems a bit of a hack, to me. I think the 
# foo:pre syntax is more explicit in expressing what you are trying to do 
# that this.
# 

Interesting.  This is obviously a very subjective thing.  To me, the 
foo:pre, foo:post style syntax reminds of this kind of anti-pattern:

my_person.parent_name = "John Smith"
my_person.parent_age = 64
my_person.parent_address = "123 Foobar Rd."

(thankfully, this is a pattern I rarely see in Ruby but often run across 
in Java programmers) :)

This code is screaming for an object to handle "parent".  But instead of 
making that object explicit, the programmer is using special-case 
programmer-specific notation to mark "parent" attributes.  foo:pre looks 
the same to me.  It takes something that feels like it should stand on its 
own two feet, and makes it instead piggy back as a symbol matching/parsing 
hack on top of the current "def" mechanism.

At any rate, I'm not going to lose any sleep or be unhappy if the original 
matz proposal wins out.  6 of one--a half dozen of the other, ultimately.

Chad