From: Dave Thomas <Dave@...>
Date: 2002-08-10T04:30:28+09:00
Subject: Re: ambiguity between local variable assignment and writter method

GOTO Kentaro <gotoken@notwork.org> writes:

> But what will I get from:  puts .setter = 123

Gotoken:

I'm guessing that the parser can distinguish the 'start of something'
state from the rest (where 'something' is to be discussed :) So, in
the case you give Ruby would pass the 'setter' message to the object
in the variable 'puts'. However, if we disambiguate with parentheses:

   puts(.setter = 123)

would execute as  puts(self.setter = 123)

> Well, I know that this probrem is considered one of pit hole.  But
> this syntax may lead implicitly us to a style: Use @var rather than
> var() even if that is a simple attribute.  Indeed I prefer @var or
> @var=val bacause the semantics of theml are simpler and clearer then
> #var() or #var=(val).

This is an interesting issue: should internal users go via the setter
method or access the instance variable directly. Clearly it depends on
the circumstances, but I often find myself writing accessors that do
things such as lazy evaluation, or which set dirty flags for
persistent objects, and where I really do need to go via the method
form. For those times, it's nice to have a shortcut, but it isn't
something I'd fight hard for... :)


Regards


Dave