Title: Select a guard expression
Goal: Generalize the function `f/2' by selecting the guard expression `A > 0, B > 0', the a new parameter is `Positive'.
Parameters: [{file,"gen21.erl"},{posrange,{56,63}},{varname,"Positive"}].
Documentation: The selected guard is a conjunction. There is not any variable with the name `Positive', so it is possible to introduce a new pattern and replace this conjunction with a simple variable with the name `Positive'. An `andalso' expression (`G > 0 andalso 3 > 0') is created and added to the argument list of the function call. 
