map _1 _2

[kazu-yamamoto]

@serras You said "Added a new refinement command which rewrites a hole or undefined via an expression, including any new holes that may be needed. For example, if a hole _ is rewriten by map, the hole will change into map _1 _2" in #296.

I don't understand this. Please give me a more concrete example?

[serras]

Let's say you have the following code in the file:

filterNothing :: [Maybe a] -> [a]
filterNothing xs = _body

Now, you put the cursor over _body and start the refining command. It asks you for an expression to refine. Say you say, filter, for example. Since filter has type (a -> Bool) -> [a] -> [a], it needs two more parameters for you to get a [a], thus the code changes to:

filterNothing xs = filter _body_1 _body_2

Note that if you instead had written the code as

filterNothing = _body

(without any argument), it notices that you only need one parameter and would change the body to filter _body_1.

[kazu-yamamoto]

Ah, we need to type C-cC-f, right?

[serras]

Yep.

[serras]

As mentioned in #308, I think that refine should stay in its own key binding C-c C-f instead of being merged with M-t.

[kazu-yamamoto]

I think it is reasonable because refine requires user input while M-t does not. :-)

[kazu-yamamoto]

Closing.