Catching line numbers in ruby exceptions

Question

p e.backtrace

I ran it on an IRB session which has no source and it still gave relevant info.

=> ["(irb):11:in `foo'", 
    "(irb):17:in `irb_binding'", 
     "/usr/lib64/ruby/1.8/irb/workspace.rb:52:in `irb_binding'", 
     "/usr/lib64/ruby/1.8/irb/workspace.rb:52"]

If you want a nicely parsed backtrace, the following regex might be handy:

p x.backtrace.map{ |x|   
     x.match(/^(.+?):(\d+)(|:in `(.+)')$/); 
    [$1,$2,$4] 
}

[
  ["(irb)", "11", "foo"], 
  ["(irb)", "48", "irb_binding"], 
  ["/usr/lib64/ruby/1.8/irb/workspace.rb", "52", "irb_binding"], 
  ["/usr/lib64/ruby/1.8/irb/workspace.rb", "52", nil]
]

( Regex /should/ be safe against weird characters in function names or directories/filenames )
( If you’re wondering where foo camefrom, i made a def to grab the exception out :

>>def foo
>>  thisFunctionDoesNotExist
>> rescue Exception => e 
>>   return e 
>>end     
>>x = foo 
>>x.backtrace

Leave a Comment Cancel reply