From: Sharon Rosner <ciconia@...>
Date: 2007-09-21T01:57:16+09:00
Subject: Ruby parser wierdness?

Hi gang

I've stumbled upon a weird phenomenon when trying nested Dataset#query
methods with Sequel:

  ds = DB[:items].query do
    select :x, :y
    where :x => DB[:stuff].query do
      select :a
      where :b => DB[:misc].query do
        select :c
        where :d => true
      end
    end
  end

  #=> /usr/local/lib/ruby/gems/1.8/gems/sequel-0.2.0.2/lib/sequel/../
sequel/dataset/convenience.rb:217:in `instance_eval': block not
supplied (ArgumentError)

If I enclose the nested procs in parens everything works fine:

  ds = DB[:items].query do
    select :x, :y
    where :x => (DB[:stuff].query do
      select :a
      where :b => (DB[:misc].query do
        select :c
        where :d => true
      end)
    end)
  end

It also works if I use the curly brackets notation:

  ds = DB[:items].query {
    select :x, :y
    where :x => DB[:stuff].query {
      select :a
      where :b => DB[:misc].query {
        select :c
        where :d => true
      }
    }
  }

Is the error above the intended behavior? If it is, can someone
explain what's going on?

best
Sharon