# frozen_string_literal: false
#
# frame.rb -
# $Release Version: 0.9$
# $Revision$
# by Keiju ISHITSUKA(Nihon Rational Software Co.,Ltd)
#
# --
#
#
#
module IRB
class Frame
class FrameOverflow < StandardError
def initialize
super("frame overflow")
end
end
class FrameUnderflow < StandardError
def initialize
super("frame underflow")
end
end
# Default number of stack frames
INIT_STACK_TIMES = 3
# Default number of frames offset
CALL_STACK_OFFSET = 3
# Creates a new stack frame
def initialize
@frames = [TOPLEVEL_BINDING] * INIT_STACK_TIMES
end
# Used by Kernel#set_trace_func to register each event in the call stack
def trace_func(event, file, line, id, binding)
case event
when 'call', 'class'
@frames.push binding
when 'return', 'end'
@frames.pop
end
end
# Returns the +n+ number of frames on the call stack from the last frame
# initialized.
#
# Raises FrameUnderflow if there are no frames in the given stack range.
def top(n = 0)
bind = @frames[-(n + CALL_STACK_OFFSET)]
fail FrameUnderflow unless bind
bind
end
# Returns the +n+ number of frames on the call stack from the first frame
# initialized.
#
# Raises FrameOverflow if there are no frames in the given stack range.
def bottom(n = 0)
bind = @frames[n]
fail FrameOverflow unless bind
bind
end
# Convenience method for Frame#bottom
def Frame.bottom(n = 0)
@backtrace.bottom(n)
end
# Convenience method for Frame#top
def Frame.top(n = 0)
@backtrace.top(n)
end
# Returns the binding context of the caller from the last frame initialized
def Frame.sender
eval "self", @backtrace.top
end
@backtrace = Frame.new
set_trace_func proc{|event, file, line, id, binding, klass|
@backtrace.trace_func(event, file, line, id, binding)
}
end
end
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