Changes between Initial Version and Version 1 of RefactoringSteps/DuplicateCodeElimination

Timestamp:

Mar 11, 2015, 10:48:02 AM (11 years ago)

Author:

manualwiki

Comment:

--

RefactoringSteps/DuplicateCodeElimination

@@ +1 @@
+= Duplicate Code Elimination =
+
+The “ Duplicate Code Elimination” transformation eliminates a duplicate code group. This transformation needs a duplicate code group found with the filtered_suffix_tree algorithm, with max_invalid_seq length parameter set to 0. If the members of the group are found in different modules the transformation asks the user to enter a module name where the extracted function should be placed, and exported. Every occurrence of the group will be replaced with a function call to the extracted function. The transformation asks the user to enter the extracted function's name.
+
+
+
+Eliminate a clone gorup:
+
+{{{
+-module(clone).
+
+-export([f/0, g/0]).
+
+f() ->
+   A = 5,
+   B = A + A,
+   case A of
+      5 -> io:format("~p~n",[A]);
+      _ -> io:format("Function f")
+   end.
+
+g() ->
+   C = 6,
+   case C of
+      6 -> io:format("~p~n",[C]);
+      _ -> io:format("Function g")
+   end.
+}}}
+
+Result:
+
+{{{
+-module(clone).
+
+-export([f/0, g/0]).
+
+f() ->
+   A = 5,
+   B = A + A,
+   new_fun(A, 5, "Function f").
+
+g() ->
+   C = 6,
+   new_fun(C, 6, "Function g").
+
+new_fun(NewVar1, NewVar2, NewVar3) ->
+    case NewVar1 of
+      NewVar2 -> io:format("~p~n",[NewVar1]);
+      _       -> io:format(NewVar3)
+   end.
+}}}
+
+== Side conditions ==
+
+ * The extracted function name should not conflict with an already used function name.
+
+
+== Transformation steps and compensations ==
+
+ 1. Given the clone name, clone group, the transformation analyses the group and finds the variables which will be extracted.
+ 2. Calls the extract_funcion transformation to create a new function, and replaces the group members to a call to the extracted function.