debug_command

# File lib/debug.rb, line 381
    def debug_command(file, line, id, binding)
      MUTEX.lock
      unless defined?($debugger_restart) and $debugger_restart
        callcc{|c| $debugger_restart = c}
      end
      set_last_thread(Thread.current)
      frame_pos = 0
      binding_file = file
      binding_line = line
      previous_line = nil
      if ENV['EMACS']
        stdout.printf "\0032\0032%s:%d:\n", binding_file, binding_line
      else
        stdout.printf "%s:%d:%s", binding_file, binding_line,
          line_at(binding_file, binding_line)
      end
      @frames[0] = [binding, file, line, id]
      display_expressions(binding)
      prompt = true
      while prompt and input = readline("(rdb:%d) "%thnum(), true)
        catch(:debug_error) do
          if input == ""
            next unless DEBUG_LAST_CMD[0]
            input = DEBUG_LAST_CMD[0]
            stdout.print input, "\n"
          else
            DEBUG_LAST_CMD[0] = input
          end

          case input
          when /^\s*tr(?:ace)?(?:\s+(on|off))?(?:\s+(all))?$/
            if defined?( $2 )
              if $1 == 'on'
                set_trace_all true
              else
                set_trace_all false
              end
            elsif defined?( $1 )
              if $1 == 'on'
                set_trace true
              else
                set_trace false
              end
            end
            if trace?
              stdout.print "Trace on.\n"
            else
              stdout.print "Trace off.\n"
            end

          when /^\s*b(?:reak)?\s+(?:(.+):)?([^.:]+)$/
            pos = $2
            if $1
              klass = debug_silent_eval($1, binding)
              file = $1
            end
            if pos =~ /^\d+$/
              pname = pos
              pos = pos.to_i
            else
              pname = pos = pos.intern.id2name
            end
            break_points.push [true, 0, klass || file, pos]
            stdout.printf "Set breakpoint %d at %s:%s\n", break_points.size, klass || file, pname

          when /^\s*b(?:reak)?\s+(.+)[#.]([^.:]+)$/
            pos = $2.intern.id2name
            klass = debug_eval($1, binding)
            break_points.push [true, 0, klass, pos]
            stdout.printf "Set breakpoint %d at %s.%s\n", break_points.size, klass, pos

          when /^\s*wat(?:ch)?\s+(.+)$/
            exp = $1
            break_points.push [true, 1, exp]
            stdout.printf "Set watchpoint %d:%s\n", break_points.size, exp

          when /^\s*b(?:reak)?$/
            if break_points.find{|b| b[1] == 0}
              n = 1
              stdout.print "Breakpoints:\n"
              break_points.each do |b|
                if b[0] and b[1] == 0
                  stdout.printf "  %d %s:%s\n", n, b[2], b[3]
                end
                n += 1
              end
            end
            if break_points.find{|b| b[1] == 1}
              n = 1
              stdout.print "\n"
              stdout.print "Watchpoints:\n"
              for b in break_points
                if b[0] and b[1] == 1
                  stdout.printf "  %d %s\n", n, b[2]
                end
                n += 1
              end
            end
            if break_points.size == 0
              stdout.print "No breakpoints\n"
            else
              stdout.print "\n"
            end

          when /^\s*del(?:ete)?(?:\s+(\d+))?$/
            pos = $1
            unless pos
              input = readline("Clear all breakpoints? (y/n) ", false)
              if input == "y"
                for b in break_points
                  b[0] = false
                end
              end
            else
              pos = pos.to_i
              if break_points[pos-1]
                break_points[pos-1][0] = false
              else
                stdout.printf "Breakpoint %d is not defined\n", pos
              end
            end

          when /^\s*disp(?:lay)?\s+(.+)$/
            exp = $1
            display.push [true, exp]
            stdout.printf "%d: ", display.size
            display_expression(exp, binding)

          when /^\s*disp(?:lay)?$/
            display_expressions(binding)

          when /^\s*undisp(?:lay)?(?:\s+(\d+))?$/
            pos = $1
            unless pos
              input = readline("Clear all expressions? (y/n) ", false)
              if input == "y"
                for d in display
                  d[0] = false
                end
              end
            else
              pos = pos.to_i
              if display[pos-1]
                display[pos-1][0] = false
              else
                stdout.printf "Display expression %d is not defined\n", pos
              end
            end

          when /^\s*c(?:ont)?$/
            prompt = false

          when /^\s*s(?:tep)?(?:\s+(\d+))?$/
            if $1
              lev = $1.to_i
            else
              lev = 1
            end
            @stop_next = lev
            prompt = false

          when /^\s*n(?:ext)?(?:\s+(\d+))?$/
            if $1
              lev = $1.to_i
            else
              lev = 1
            end
            @stop_next = lev
            @no_step = @frames.size - frame_pos
            prompt = false

          when /^\s*w(?:here)?$/, /^\s*f(?:rame)?$/
            display_frames(frame_pos)

          when /^\s*l(?:ist)?(?:\s+(.+))?$/
            if not $1
              b = previous_line ? previous_line + 10 : binding_line - 5
              e = b + 9
            elsif $1 == '-'
              b = previous_line ? previous_line - 10 : binding_line - 5
              e = b + 9
            else
              b, e = $1.split(/[-,]/)
              if e
                b = b.to_i
                e = e.to_i
              else
                b = b.to_i - 5
                e = b + 9
              end
            end
            previous_line = b
            display_list(b, e, binding_file, binding_line)

          when /^\s*up(?:\s+(\d+))?$/
            previous_line = nil
            if $1
              lev = $1.to_i
            else
              lev = 1
            end
            frame_pos += lev
            if frame_pos >= @frames.size
              frame_pos = @frames.size - 1
              stdout.print "At toplevel\n"
            end
            binding, binding_file, binding_line = @frames[frame_pos]
            stdout.print format_frame(frame_pos)

          when /^\s*down(?:\s+(\d+))?$/
            previous_line = nil
            if $1
              lev = $1.to_i
            else
              lev = 1
            end
            frame_pos -= lev
            if frame_pos < 0
              frame_pos = 0
              stdout.print "At stack bottom\n"
            end
            binding, binding_file, binding_line = @frames[frame_pos]
            stdout.print format_frame(frame_pos)

          when /^\s*fin(?:ish)?$/
            if frame_pos == @frames.size
              stdout.print "\"finish\" not meaningful in the outermost frame.\n"
            else
              @finish_pos = @frames.size - frame_pos
              frame_pos = 0
              prompt = false
            end

          when /^\s*cat(?:ch)?(?:\s+(.+))?$/
            if $1
              excn = $1
              if excn == 'off'
                @catch = nil
                stdout.print "Clear catchpoint.\n"
              else
                @catch = excn
                stdout.printf "Set catchpoint %s.\n", @catch
              end
            else
              if @catch
                stdout.printf "Catchpoint %s.\n", @catch
              else
                stdout.print "No catchpoint.\n"
              end
            end

          when /^\s*q(?:uit)?$/
            input = readline("Really quit? (y/n) ", false)
            if input == "y"
              exit!  # exit -> exit!: No graceful way to stop threads...
            end

          when /^\s*v(?:ar)?\s+/
            debug_variable_info($', binding)

          when /^\s*m(?:ethod)?\s+/
            debug_method_info($', binding)

          when /^\s*th(?:read)?\s+/
            if DEBUGGER__.debug_thread_info($', binding) == :cont
              prompt = false
            end

          when /^\s*pp\s+/
            PP.pp(debug_eval($', binding), stdout)

          when /^\s*p\s+/
            stdout.printf "%s\n", debug_eval($', binding).inspect

          when /^\s*r(?:estart)?$/
            $debugger_restart.call

          when /^\s*h(?:elp)?$/
            debug_print_help()

          else
            v = debug_eval(input, binding)
            stdout.printf "%s\n", v.inspect
          end
        end
      end
      MUTEX.unlock
      resume_all
    end