Changes between Initial Version and Version 1 of RefactoringSteps/UpgradeModuleInterface

Timestamp:

Feb 19, 2012, 11:31:51 PM (12 years ago)

Author:

manualwiki

Comment:

--

RefactoringSteps/UpgradeModuleInterface

@@ +1 @@
+= Upgrade module interface =
+
+This transformation upgrades the calls of the old regular expression module regexp to the new re module. The transformation is based on a generic interface upgrade module, which is invoked with the right structural and semantic change descriptors.
+
+An example of upgrading regexp interface:
+
+{{{
+case regexp:match(String, RE) of
+   {error, Reason} -> throw("Error: " ++ lists:flatten(
+                        regexp:format_error(Reason)));
+   {match, 1, Len} -> Len;
+   {match, St, Len} -> use(St, Len);
+   nomatch -> ok
+end
+}}}
+
+Result:
+
+{{{
+try re:run(String, RE, [{capture, first}]) of
+   {match, [{0, Len}]} -> Len;      % [{1-1, Len}] works too
+   {match, [{St, Len}]} -> use(St+1, Len);
+   nomatch -> ok
+catch
+   error:badarg -> throw("Error: " ++ lists:flatten(
+                     "Bad regular expression"))
+end
+}}}
+
+
+== Side conditions ==
+
+ * Patterns belong to applications to be updated should match at least one of the patterns written in the change descriptors.
+
+
+== Transformation steps and compensations ==
+
+ 1. Updating the function application:
+  * Modifying the called function’s identifier {{{regexp:match ->re:run}}}
+  * Matching the old function arguments and creating the new argument list {{{(String, RE) -> (String, RE, [capture, first])}}}
+
+ 2. Finding the patterns to be updated and performing on them the matching and the replacing. Furthermore, applying the correction functions on the variable bindings or/and usages.
+  * Pattern: {{{match, 1, Len -> match, [0, Len]}}}
+  * Expression: {{{use(St, Len) -> use(St+1, Len)}}}
+
+ 3.  Turning the case expression to a try expression and moving error pattern to the catch block (error:badarg is moved to a catch block after we changed case expression to try expression).