From: Marcello Barnaba <bofh@...>
Date: 2007-02-21T03:53:57+09:00
Subject: Re: adding local variables via block

Hi,

On Tuesday 20 February 2007 19:33, Paul Danese wrote:
> ####################
> def lamb_test �
> � � cond = 'hello'
> � � yield
> � � puts cond + ' ' + name
> � end
>
> lamb_test {name = 'bob'}
>
> ###################

the local variables defined in the block live only in the block's scope. if a 
local variable is defined out of the block, a closure is made and you can 
access (and redefine) that variable in the block:

>> a = 1
=> 1
>> p = proc { a = 2; b = 3 }
=> #<Proc:0xb7ae7150@(irb):8>
>> p.call
=> 2
>> a
=> 2
>> b
=> NameError: ...

> Is there a better way?

well

def lamb_test
  cond = 'hello'
  name = yield
  puts cond + ' ' + name
end

better:

def lamb_test
  cond = hello
  puts cond + ' ' + yield
end

better:

def lamb_test
  puts ['hello', yield].join(' ')
end

even better:

def lamb_test
  ['hello', yield].join(' ')
end

puts lamb_test { 'world' }

if "puts" is not strictly necessary in your method, take it out, and just 
return a string. this way, when you need to print that string on something 
different than a text terminal, you don't need to mess with the class you've 
written earlier.

HTH! :)
-- 
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