From: Chris Hall <christopher.k.hall@...>
Date: 2007-09-20T02:44:03+09:00
Subject: exceptions and eval'ing a string

Here's my situation


I have a setup such as:

----task.rb----
class Task
  def initialize(name, &action)
    @name = name
    @action = action
  end

  def run
    @action.call(self)
  end
end

----task_runner.rb----
require 'task'

t = Task.new('task_1') { |t| puts t.name }
t.run # => thing


what i am now trying to do is put the Task creation code inside a file
and eval that as a string

----thing.task----
Task.new('task_1') P |t| puts t.name }


----task_runner.rb----
require 'task'
def load_task
  @t = eval('thing.task')
end

@t = nil
load_task
@t.run

and this works...however, the difference is that if an exception is
thrown as part of the Task's action (when it is run) eval craps out with
an exception like

(eval):15

and it brings down the entire script, which is a bad thing because i'm
running each task in a thread.  this doesn't happen obviously when i'm
not eval'ing.

can someone explain to me what is going on?  I'm thinking it's a
scoping/context thing, but i'm not really sure.

Chris
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