el-patch convenience directives to emulate advice-add

[Luis-Henriquez-Perez]

There are some functions that I can customize to my liking by either using around advice or overriding advice as opposed to copying the whole to my init file and using the el-patch directives. However, I'd still like the ability to track if any changes have occurred to the original definitions.

I know that if I wanted to emulate overriding, for example, I can do:
(el-patch-defun my-fun (args) (el-patch-swap (long original definition that I don't want to copy into my init file...) (new definition))

However I'd like to be able to do something like:
(el-patch-defun my-fun (args) (el-patch-override (new-definition)).

Where el-patch-override would be the same as el-patch-swap but using the whole definition.

I think what I'm asking boils down to:
Does el-patch provide a way to reference the definition original function definition without writing it out?
Does el-patch provide a way to define my own custom directives (so I could create el-patch-override)?

[raxod502]

Maybe this is a dumb question, but what's wrong with advice? M-x describe-function lists all the advice that has been added to a function, and lets you jump to the source code of each advice function.

[Luis-Henriquez-Perez]

No, it's not a dumb question.

I was wondering this: if el-patch lets us check whether the original function has changed why use advice at all? Why not just not use el-patch for all advices? Sure functions in external emacs packages are more likely to change than built-in ones, but they can both change.

I get the feeling there's a reason why (in radian.el for example I see that you sometimes use el-patch and sometimes regular advice) but I'm not sure.

[raxod502]

Uh, how would el-patch know if the original function has changed, if you don't copy the definition into your init-file? Where would it be getting that information from?

The point of el-patch is that you should avoid it whenever you can, since advice is more lightweight, robust, and flexible.

[Luis-Henriquez-Perez]

Thanks, your answer cleared up my misunderstanding.

I'm ready to close this issue but will wait one day until doing so unless you wanted to say anything else.

[hab25]

The point of el-patch is that you should avoid it whenever you can, since advice is more lightweight, robust, and flexible.

@raxod502 what makes advice more robust and flexible?

[raxod502]

Because it doesn't need to be updated when the original code changes, unless it depends in some important functional way on the original function behavior. el-patch is for cases where you need to change a specific sub-part of a function, and can't express the change as one of the standard :override, :around, etc options.

[hab25]

Because it doesn't need to be updated when the original code changes

But , given that el-patch-define-template exists (n.b. its interaction with '...) this is true for el-patch as well, no? AFAICT by using templates, every single one of the :override, :around, etc can be expressed (i.e. in a way that matches requirements for updates identically in all cases).

To be clear; I'm not trying to cause annoyance by nitpicking correctness; I'm trying to clarify my understanding.

[raxod502]

Yeah, I guess now that templates have been added, you could use them to achieve more or less the same thing as advice. I don't know that they would support stacking and ordering though. You can have arbitrarily many advices registered by different systems and they will all work together in a defined way. I don't think that would be the case with el-patch, which is really intended only for use in the end user's configuration.

[hab25]

Yeah, I guess now that templates have been added, you could use them to achieve more or less the same thing as advice. I don't know that they would support stacking and ordering though. You can have arbitrarily many advices registered by different systems and they will all work together in a defined way. I don't think that would be the case with el-patch, which is really intended only for use in the end user's configuration.

Makes sense, thank you.