Outputs a source level execution trace of a Ruby program.

It does this by registering an event handler with Kernel#set_trace_func for processing incoming events. It also provides methods for filtering unwanted trace output (see Tracer.add_filter, Tracer.on, and Tracer.off).

Example

Consider the following Ruby script

class A
  def square(a)
    return a*a
  end
end

a = A.new
a.square(5)

Running the above script using ruby -r tracer example.rb will output the following trace to STDOUT (Note you can also explicitly require ‘tracer’)

#0:<internal:lib/rubygems/custom_require>:38:Kernel:<: -
#0:example.rb:3::-: class A
#0:example.rb:3::C: class A
#0:example.rb:4::-:   def square(a)
#0:example.rb:7::E: end
#0:example.rb:9::-: a = A.new
#0:example.rb:10::-: a.square(5)
#0:example.rb:4:A:>:   def square(a)
#0:example.rb:5:A:-:     return a*a
#0:example.rb:6:A:<:   end
 |  |         | |  |
 |  |         | |   ---------------------+ event
 |  |         |  ------------------------+ class
 |  |          --------------------------+ line
 |   ------------------------------------+ filename
  ---------------------------------------+ thread

Symbol table used for displaying incoming events:

+}+

call a C-language routine

+{+

return from a C-language routine

+>+

call a Ruby method

C

start a class or module definition

E

finish a class or module definition

-

execute code on a new line

+^+

raise an exception

+<+

return from a Ruby method

Copyright

by Keiju ISHITSUKA(keiju@ishitsuka.com)

Constants

Single = new

EVENT_SYMBOL = { "line" => "-", "call" => ">", "return" => "<", "class" => "C", "end" => "E", "raise" => "^", "c-call" => "}", "c-return" => "{", "unknown" => "?" }

Attributes

[RW] display_c_call?

display C-routine calls in trace output (defaults to false)
[RW] display_c_call

display C-routine calls in trace output (defaults to false)
[RW] display_thread_id?

display thread id in trace output (defaults to true)
[RW] display_thread_id

display thread id in trace output (defaults to true)
[RW] display_process_id?

display process id in trace output (defaults to false)
[RW] display_process_id

display process id in trace output (defaults to false)
[R] stdout_mutex

mutex lock used by tracer for displaying trace output
[RW] stdout

output stream used to output trace (defaults to STDOUT)
[RW] verbose?

display additional debug information (defaults to false)
[RW] verbose

display additional debug information (defaults to false)
Show files where this class is defined (2 files)
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