From: "Matthias Wächter" <matthias@...>
Date: 2007-09-04T23:15:58+09:00
Subject: Re: with

On 04.09.2007 15:28, Paul Brannan wrote:
> On Tue, Sep 04, 2007 at 06:50:43AM +0900, Matthias W?chter wrote:
>> Ruby tries to avoid local variables wherever it can by chaining
>> iterators together like in file-open-each-line-gsub. I tried to allow
>> a block to be used for non-enumerable types as well.
> 
> Ruby doesn't try to avoid local variables; this is something you have
> done.  IMO it's not a good idea.  If there's a bug anywhere in your
> chain and one of the methods you call returns the wrong type (nil, for
> example), then debugging becomes more difficult.

Flow is generally from top to bottom (in a file) and from left to
right in a line. If there were not function calling and assignment
which work some kind of upstream, i.e. right to left. .with
introduces downstream function calling without the need for
rewriting code _around_ the whole statement and introducing more
variables.

It even helps debugging. If I am not sure about a value I can simply
add ".with {|x| puts "Debugging the expression: #{x}"}" within an
expression. Certainly, I might have to add a paren around the
expression for ordering stuff correctly, but I don't have to split
things apart.

FWIW, I have not touched the field of debugging with Ruby yet, so
allow me a second opinion on this later :)

- Matthias