2000-05-12

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@687 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/irb/frame.rb

@@ -0,0 +1,67 @@
+#
+#   frame.rb - 
+#   	$Release Version: 0.6$
+#   	$Revision$
+#   	$Date$
+#   	by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd)
+#
+# --
+#
+#   
+#
+
+require "e2mmap"
+
+module IRB
+  class Frame
+    extend Exception2MessageMapper
+    def_exception :FrameOverflow, "frame overflow"
+    def_exception :FrameUnderflow, "frame underflow"
+
+    INIT_STACK_TIMES = 3
+    CALL_STACK_OFFSET = 3
+
+    def initialize
+      @frames = [TOPLEVEL_BINDING] * INIT_STACK_TIMES
+    end
+
+    def trace_func(event, file, line, id, binding)
+      case event
+      when 'call', 'class'
+	@frames.push binding
+      when 'return', 'end'
+	@frames.pop
+      end
+    end
+
+    def top(n = 0)
+      bind = @frames[-(n + CALL_STACK_OFFSET)]
+      Fail FrameUnderflow unless bind
+      bind
+    end
+
+    def bottom(n = 0)
+      bind = @frames[n]
+      Fail FrameOverflow unless bind
+      bind
+    end
+
+    # singleton functions
+    def Frame.bottom(n = 0)
+      @backtrace.bottom(n)
+    end
+
+    def Frame.top(n = 0)
+      @backtrace.top(n)
+    end
+
+    def Frame.sender
+      eval "self", @backtrace.top
+    end
+
+    @backtrace = Frame.new
+    set_trace_func proc{|event, file, line, id, binding|
+      @backtrace.trace_func(event, file, line, id, binding)
+    }
+  end
+end