From: Chris Hall <christopher.k.hall@...>
Date: 2007-09-20T03:12:27+09:00
Subject: Re: exceptions and eval'ing a string

sorry, there's a typo in the example, that eval line should read

@t = eval(IO.read("test.task"))

rather than

@t = eval("test.task")

problem still stands.

Chris Hall wrote:
> 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

-- 
Posted via http://www.ruby-forum.com/.