# Trapping error not caught by rescue Exception -- How to? **URL:** \ **Category:** ruby-talk\ **Created:** [17 December 2006 02:50 UTC](https://rubytalk.org/t/trapping-error-not-caught-by-rescue-exception-how-to/33797 "2006-12-17T02:50:07Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [17 December 2006 02:50 UTC](https://rubytalk.org/t/trapping-error-not-caught-by-rescue-exception-how-to/33797/1 "2006-12-17T02:50:07Z")
Hi, The fourth data line in the program below hangs rather than submitting to the rescue clause. How can I trap that kind of error? I'm running WinXP-Pro/SP2, Ruby 1.8.2-15, Rails 1.1.6, MySQL 5.0.15-nt, SciTE 1.59 TIA, Richard === code start === begin   DATA.each do |line|     var, expr, excess = line.chomp.split(/=/, 3)     var.strip!; expr.strip!     puts "expr=" + expr + ", expr.class=" +expr.class.to\_s     puts "eval(expr)=" + eval(expr).to\_s   end rescue Exception =\> eMsg   puts "ERROR: " + eMsg   retry end \_\_END\_\_ a = 5\*\*2 =# 25 b =date =# undefined local variable or method `date' for main:Object c = y =# undefined local variable or method `y' for main:Object c =`date` =# (ruby hangs; Ctrl-C kills it) === code end === ---
**Author:** ![Daniel\_Finnie1](https://avatars.discourse-cdn.com/v4/letter/d/4af34b/32.png) [@Daniel\_Finnie1](https://rubytalk.org/u/Daniel_Finnie1)\ **Post date:** [17 December 2006 03:04 UTC](https://rubytalk.org/t/trapping-error-not-caught-by-rescue-exception-how-to/33797/2 "2006-12-17T03:04:32Z")
Ruby doesn't hang when I run that code. This is the output: daniel@daniel-desktop:~$ ruby /tmp/tmp.rb expr=5\*\*2, expr.class=String eval(expr)=25 expr=date, expr.class=String ERROR: undefined local variable or method `date' for main:Object ERROR: undefined method `strip!' for nil:NilClass expr=y, expr.class=String ERROR: undefined local variable or method `y' for main:Object expr=`date`, expr.class=String eval(expr)=Sat Dec 16 22:01:37 EST 2006 Richard wrote: > **···** > > > Hi, > > > > The fourth data line in the program below hangs rather than submitting > > to the rescue clause. How can I trap that kind of error? > > > > I'm running WinXP-Pro/SP2, Ruby 1.8.2-15, Rails 1.1.6, MySQL > > 5.0.15-nt, SciTE 1.59 > > > > TIA, > > Richard > > > > === code start === > > begin > >   DATA.each do |line| > >     var, expr, excess = line.chomp.split(/=/, 3) > >     var.strip!; expr.strip! > >     puts "expr=" + expr + ", expr.class=" +expr.class.to\_s > >     puts "eval(expr)=" + eval(expr).to\_s > >   end > > rescue Exception =\> eMsg > >   puts "ERROR: " + eMsg > >   retry > > end > > > > \_\_END\_\_ > > a = 5\*\*2 =# 25 > > b =date =# undefined local variable or method `date' for > > main:Object > > c = y =# undefined local variable or method `y' for main:Object > > c =`date` =# (ruby hangs; Ctrl-C kills it) > > === code end === ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [17 December 2006 04:05 UTC](https://rubytalk.org/t/trapping-error-not-caught-by-rescue-exception-how-to/33797/3 "2006-12-17T04:05:09Z")
Hi Daniel, Thanks for your results. I suspect you were running on Uni\*. I was running in SciTE over WindowsXP. When I ran the program in a Command window, I saw what the problem is: in Windows, the date command waits for keyboard input specifying a new system date. That wasn't apparent when I was running under SciTE. So, all's well in my Ruby sandbox. Regards, Richard Daniel Finnie wrote: > **···** > > > Ruby doesn't hang when I run that code. > > > > This is the output: > > daniel@daniel-desktop:~$ ruby /tmp/tmp.rb > > expr=5\*\*2, expr.class=String > > eval(expr)=25 > > expr=date, expr.class=String > > ERROR: undefined local variable or method `date' for main:Object > > ERROR: undefined method `strip!' for nil:NilClass > > expr=y, expr.class=String > > ERROR: undefined local variable or method `y' for main:Object > > expr=`date`, expr.class=String > > eval(expr)=Sat Dec 16 22:01:37 EST 2006 > > > > Richard wrote: > > \> Hi, > > \> > > \> The fourth data line in the program below hangs rather than submitting > > \> to the rescue clause. How can I trap that kind of error? > > \> > > \> I'm running WinXP-Pro/SP2, Ruby 1.8.2-15, Rails 1.1.6, MySQL > > \> 5.0.15-nt, SciTE 1.59 > > \> > > \> TIA, > > \> Richard > > \> > > \> === code start === > > \> begin > > \> DATA.each do |line| > > \> var, expr, excess = line.chomp.split(/=/, 3) > > \> var.strip!; expr.strip! > > \> puts "expr=" + expr + ", expr.class=" +expr.class.to\_s > > \> puts "eval(expr)=" + eval(expr).to\_s > > \> end > > \> rescue Exception =\> eMsg > > \> puts "ERROR: " + eMsg > > \> retry > > \> end > > \> > > \> \_\_END\_\_ > > \> a = 5\*\*2 =# 25 > > \> b =date =# undefined local variable or method `date' for > > \> main:Object > > \> c = y =# undefined local variable or method `y' for main:Object > > \> c =`date` =# (ruby hangs; Ctrl-C kills it) > > \> === code end === > > \> > > \> > > \>