rel=me » set_trace_func http://rel.me programming, objective-c, cocoa, iphone, c Wed, 01 Feb 2012 07:26:50 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 set_trace_func and filter on regex http://rel.me/2007/08/29/trace-with-regex/ http://rel.me/2007/08/29/trace-with-regex/#comments Wed, 29 Aug 2007 00:58:00 +0000 admin /2007/09/03/trace-with-regex I needed to use the trace_func to figure out a bug, and I came up with:

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  class Tracer
    
    class << self
      
      def on(io = STDERR, regex = nil)
        set_trace_func proc { |event, file, line, id, binding, classname|
          if !regex.blank?
            s = format("%8s %s:%-2d %10s %8s\n", event, file, line, id, classname)
            io.printf(s) if s =~ regex            
          else
            io.printf("%8s %s:%-2d %10s %8s\n", event, file, line, id, classname)
          end
        }
      end
    
      def off
        set_trace_func nil
      end
    
      def trace(io = STDERR, regex = nil, &block)
        on(io, regex)
        retval = yield if block_given?
        off      
        retval
      end
      
    end
  end
  
end

Then Tracer.trace { 1 + 1 } or specify a regex filter:

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>> Tracer.trace(STDERR, /Fixnum/) { 1 + 1 }
  c-call (irb):2           +   Fixnum
c-return (irb):2           +   Fixnum
=> 2
>>
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