From: Ken Bloom <kbloom@...>
Date: 2009-03-05T02:38:49+09:00
Subject: Re: Any solutions to Ruby's inconsistencies?

On Wed, 04 Mar 2009 11:02:36 -0500, C. Dagnon wrote:

> Ruby has definite positives over Java and even other scripting
> languages, but many negatives too.  One negative is the inconsistency of
> how rules seem to be applied in the language and accompanying toolsets.
> Here are a few that have bitten me:
> 
> 
> 1. I almost immediately got started with Ruby on Rails and loved the
> idea of partials, but then I found that the ||= idiom doesn't work on
> partials' parameters.
> 
> <%  my_param_a ||= 1    # Errors out
>     my_param_a = my_param_a ? my_param_a : 1   # works
> -%>
> 
> That seemed odd as I thought both were equivalent, and it broke some of
> the trust I had for Ruby.  Not as much as early Rails' use of 2 separate
> variables for RAILS_ENV, but...

I don't use rails, and I don't know what a partial is, so I can't answer. 
You probably better ask on a Rails list.

> 2. Then when using blocks to process an array I tried to use another
> Ruby control structure:
> 
>   arr=[1,2,3,4]
>   arr2 = arr.collect{|ii|  return 0 if ii == 3; ii+1} # result:
>   LocalJumpError: unexpected return
> 
> That also caught me off guard - I need the block to return a value, to
> evaluate to a value - but suddenly I'm told that 'return' doesn't mean
> what I think it means?  At least not inside a block (or Proc.new)...

A block (except when it's a lambda) is meant to be looked at as though 
it's a control structure in the function, the same as if it were an 
ordinary loop. So the idea of `return` is to return from the function. 
Use `next` to return a value early from the block.

arr2 = arr.collect{|ii|  next 0 if ii == 3; ii+1}


> 4. And what's up with Ruby incorrectly naming their Map 'Hash'?  Or is
> my C.S. idea of a Hash too limited?  Granted in Java they have HashMap,
> but if you enter one value and get a second one out it is a Map,
> regardless of how the keys are stored.  A 'Hash' would instead be a type
> of set.

Perhaps they should, but it would be a pain to change it now.

--Ken


-- 
Chanoch (Ken) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/