Convert Inline Eval of a Form into a Comment (add result as a comment)

[dharrigan]

Hi,

Recently, Conjure (re-)learnt the ability to display the results of an evaluation beside the form as virtual text. This virtual text, being super doopar handy, unfortunately disappears when there is cursor movement.

It would be incredibly useful for composing results on the fly if the inline eval could also be converted into a comment which would greatly aid in train-of-thought, repl-driven development, demos, screencasts and so on. It is noted that another popular editor built upon Emacs offers this feature too (thus having a bit more parity with that would aid in people transitioning across)

A suggestion would be to use <prefix>ec to eval the form and add the result of the eval as a comment.

[emilaasa]

A great case that I use this for is rich comment forms:

(comment
  (my-fun-function good-argument) ; [1 2 3 4 5] 
  (my-fun-function bad-argument) ; OutOfMemoryError
    ) 

Another is for screencasts with limited screen real estate where this can be really effective.

[practicalli-johnny]

, e ; is the key binding I added to Spacemacs to eval a top level form to a comment.

I use eval top level form to comment extensively in my live broadcasts and screencasts, to explain what is going on with code.

I also rely on eval to comment when designing, especially with data structure design. This cuts down on cognitive load, as I have a reminder of the structure at a glance.

As mentioned by @emilaasa I also use eval to comment in rich comment blocks. This provides living documentation showing what to expect from important API calls in the namespace.

Thank you.

[sotte]

A bit hacky, but hey :)

:nmap ,ec :ConjureEval<CR>A ; <ESC>"cp                                                                                                                  

Conjure stores the results of eval in the named register c. So this mapping turns

(comment
  (a.inc 2)
  (a.inc 3)  
)

into

(comment
  (a.inc 2) ; 3
  (a.inc 3)  
)

If you want a history of your execution + results you could also use the log buffer (,lv).

[dharrigan]

Works great! Thank you.

[emilaasa]

Also testing it now and it works perfectly!

[Olical]

Going to open this up for a little longer for more work. I want to add some config so people can have it use ;; (over ;) for the comment, just because it was requested. I don't really want this feature but still, it'll improve it for some people!

I also want to refactor how you invoke this, so it becomes something like <prefix>ece for current form, <prefix>ecw for current word and <prefix>ecr for the root form. People want to be able to eval different things into comments, so I need to provide a more general system for that, <prefix>ec is too short and specific already to open this up.

So, warning, the mapping will be changing on develop before I cut a release to be more general and open to extension.

[dharrigan]

I fully support this ;-)

[emilaasa]

Looks like a great enhancement.

…

On Tue, Jan 26, 2021 at 1:00 PM David Harrigan ***@***.***> wrote: I fully support this ;-) — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#160 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADJSKXF2V5UXQWE4LVHTUXTS32VGFANCNFSM4VUYRV6Q> .

[justone]

This is a very cool feature, and one I will definitely use when pairing with others. Thanks for adding it.

[Olical]

So I've split the mapping into <prefix>ece, <prefix>ecr and <prefix>ecw which map to current/root form and current word respectively. I hope they work well for you! You can always remap "eval current form into comment" to <prefix>e; etc if you so wish! The config can all be found in :h conjure.

[Olical]

I've also added g:conjure#eval#comment_prefix which you can set to ";; " (with a trailing space) to have two semi-colon comments. I personally use single commas for any code or data and two for prose, but some people may want two everywhere.