Here are some screenshots from the example refactoring we used for the demo in Uppsala (using GVim):
The original program and the refactoring menu (detached)
First, let's generalise over the 0 in the nil-case.
Highlight the 0, select generaliseDef, and
enter n as the name of the new parameter:
That done, we do the same for the (+) in the cons-case:
Now, we better rename our function to reflect its more general
definition. Position the cursor on the start of sum, select
rename, and enter fold as the new name:
The partial application fold (+) 0 is our old sum function,
and we can introduce a definition for that expression.
Highlight the expression, select introNewDef, and enter
sum as the name for the new definition:
And since that definition might be reusable, we better move it to
the top level. Position the cursor on the start of sum, then
select liftToTopLevel:
