From: ahoward <ahoward@...>
Date: 2003-03-31T15:13:15+09:00
Subject: Re: how to catch any exception "eval" throws

On Mon, 31 Mar 2003, Meinrad Recheis wrote:

> i tried
>
> begin
> 	eval( str )
> rescue
> 	puts $!
> end
>
> but my program terminates if str contains erraneous expressions
> why doesn t rescue catch say "parser errors"?
<snip>

  ~ > cat foo.rb
  #!/usr/bin/env ruby

  %w[ error ;|;| raise('badthings') ].each do |badthing|
    begin
      eval badthing
    rescue NameError, SyntaxError, StandardError => err
      print "eval(#{badthing}) caused\n\t"
      p err
      print "\n"
    end
  end

  ~> ./foo.rb
  eval(error) caused
    #<NameError: (eval):1: undefined local variable or method `error' for #<Object:0x40190ce0>>

  eval(;|;|) caused
    #<SyntaxError: (eval):1: compile error
  (eval):1: parse error>

  eval(raise('badthings')) caused
    #<RuntimeError: (eval):1: badthings>


there are probably more to catch - but this is the bulk of them.

-a

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