From: Eivind Eklund <eeklund@...>
Date: 2007-12-11T02:45:41+09:00
Subject: Re: How much would variable declarations in Ruby make you wince?

On Dec 10, 2007 5:34 PM, Just Another Victim of the Ambient Morality
<ihatespam@hotmail.com> wrote:
>     You're really not thinking this through.
>     How on God's green Earth are you going to accidentally prepend an
> extraneous "var " (or whatever keyword is decided upon) to a variable's
> assignment.  Because this is highly unlikely, the described problem will
> only happen if you accidentally want to declare a new variable.  This is
> rather distinct from wanting to use a variable and so the bug should occur
> far less frequently...

It isn't so distinct that the error don't happen, as I've done the
error in Perl.  I suspect this has to do with the way either of us
write code; I write a lot of small methods, and I often combine
initialization and variable creation.  So, to my mind, first
initialization of a variable is mentally equivalent to declaring the
variable - so I'll just write "my" when I write the first
initialization.  When this happens to be inside a code block (e.g,
inside an if statement), I need to expand the context of the variable,
so I'll throw a declaration before the code block.

With Ruby, this is just an initialization - "variable = nil".  With
Perl it's "my variable" - alas, that variable is the shadowed by the
other my declaration I wrote later in the code and earlier in time.

I had this bug just last week.

In my opinion, the noise of repeated "var <stuff>"-declarations (or
"my <stuff>" declarations) makes the code less readable, with the
corresponding increase in correctness checking being a benefit of less
worth than the cost.  This is the same as my view of (other) type
declarations in most cases: Their cost in terms of being in the way of
code readability/transformability exceeds their benefits.

Eivind.