From: Morton Goldberg <m_goldberg@...>
Date: 2006-11-08T03:44:31+09:00
Subject: Re: Struct.new and symbol with question mark

On Nov 6, 2006, at 11:58 PM, Suraj Kurapati wrote:

> Why isn't the Struct class smart enough to detect a question mark  
> at the
> end of a member name and create the appropriate #member= and #member?
> methods?
>
>>> Klass = Struct.new :foo, :bar?
> => Klass
>
>>> x = Klass.new
> => #<struct Klass foo=nil, :bar?=nil>
>
>>> x.foo
> => nil
>
>>> x.bar?
> NoMethodError: undefined method `bar?' for #<struct Klass foo=nil,
> :bar?=nil>
>         from (irb):5
>         from :0
>
> I was expecting Klass to have the #foo, #foo=, #bar?, and #bar=  
> methods.

It doesn't work because :bar? isn't a valid symbol literal. The  
follow does work:

<code>
#! /usr/bin/env ruby -w
Baz = Struct.new(:foo, :'bar?')
z = Baz.new(42, false)
z # => #<struct Baz foo=42, bar?=false>
z.bar? # => false
</code>

Regards, Morton