From: Dave Thomas <Dave@...>
Date: 2002-02-25T01:17:34+09:00
Subject: Re: duplicate method name

Grumpy Ron Jeffries writes:

> I must be missing something, because I don't get it. What could .meth
> possibly be other than a method call? What could the stuff in parens
> possibly be other than the parameters?

It could be the start of an expression...

  def a(arg)
    arg+7
  end
    
  a (1+2) * 3    =>?

When Ruby 1.6 warns: a (...) interpreted as method call, it's saying:

  Hmm.. Look at this. I could interpret what Ron wrote as

    call 'a' passing in (1+2). Return 10, then multiply the result by 3

  or, I could interpret it as

    evaluate (1+2)*3 as an expression, and pass the result as an
    argument to the method 'a'.

  Decisions, decisions.

  I know, I'll interpret the construct a (...) as a method call (with
  arguments), and return the result.

And that's what it does. "a (...) interpreted as method call" means
that the arguments (...) were passed to the method 'a'. It _could_ be
clearer, but it does make sense and there _is_ ambiguity here in the
general case.

Then, in 1.7, the interpretation of this changes: now the whole
expression is taken as a parameter to the method. That's why the
warning changed: the (1+2)*3 is taken to be a grouped expression.

In general, it's best not to put a space between a method name and its
parameters. And the incompatibility between 1.6 and 1.7 is a damn fine
reason to run with -w all the time.


Cheers


Dave