# pops the top 2 items of the +:name+ stack; # pushes a new ValuePoint onto the +:bool+ stack, with value +true+ if the names are identical # # *needs:* 2 +:name+ # # *pushes:* 1 +:bool+ # class NameEqualQInstruction < Instruction def preconditions? needs :name, 2 end def setup @arg2 = @context.pop_value(:name) @arg1 = @context.pop_value(:name) end def derive @result = ValuePoint.new("bool", @arg1 == @arg2) end def cleanup pushes :bool, @result end end