lib/irb/frame.rb

DEFINITIONS

   1  #
   2  #   frame.rb - 
   3  #       $Release Version: 0.9$
   4  #       $Revision: 1.4 $
   5  #       $Date: 2002/07/09 11:17:16 $
   6  #       by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd)
   7  #
   8  # --
   9  #
  10  #   
  11  #
  12  
  13  require "e2mmap"
  14  
  15  module IRB
  16    class Frame
  17      extend Exception2MessageMapper
  18      def_exception :FrameOverflow, "frame overflow"
  19      def_exception :FrameUnderflow, "frame underflow"
  20  
  21      INIT_STACK_TIMES = 3
  22      CALL_STACK_OFFSET = 3
  23  
  24      def initialize
  25        @frames = [TOPLEVEL_BINDING] * INIT_STACK_TIMES
  26      end
  27  
  28      def trace_func(event, file, line, id, binding)
  29        case event
  30        when 'call', 'class'
  31          @frames.push binding
  32        when 'return', 'end'
  33          @frames.pop
  34        end
  35      end
  36  
  37      def top(n = 0)
  38        bind = @frames[-(n + CALL_STACK_OFFSET)]
  39        Fail FrameUnderflow unless bind
  40        bind
  41      end
  42  
  43      def bottom(n = 0)
  44        bind = @frames[n]
  45        Fail FrameOverflow unless bind
  46        bind
  47      end
  48  
  49      # singleton functions
  50      def Frame.bottom(n = 0)
  51        @backtrace.bottom(n)
  52      end
  53  
  54      def Frame.top(n = 0)
  55        @backtrace.top(n)
  56      end
  57  
  58      def Frame.sender
  59        eval "self", @backtrace.top
  60      end
  61  
  62      @backtrace = Frame.new
  63      set_trace_func proc{|event, file, line, id, binding, klass|
  64        @backtrace.trace_func(event, file, line, id, binding)
  65      }
  66    end
  67  end