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diff --git a/2021/talks/form.md b/2021/talks/form.md new file mode 100644 index 00000000..41ef151c --- /dev/null +++ b/2021/talks/form.md @@ -0,0 +1,113 @@ +[[!meta title="Old McCarthy Had a Form"]] +[[!meta copyright="Copyright © 2021 Ian Eure"]] +[[!inline pages="internal(2021/info/form-nav)" raw="yes"]] + +<!-- You can manually edit this file to update the abstract, add links, etc. ---> + + +# Old McCarthy Had a Form +Ian Eure + + + +Name Pronunciation: (EE-un YOU-r) + +Pronouns: he/him/his + +Preferred contact info: ian@retrospec.tv / ieure on Libera + +[[!inline pages="internal(2021/info/form-schedule)" raw="yes"]] + +<http://atomized.org/blog/2021/11/28/old-mccarthy-had-a-form/> + +Most practical languages are multi-paradigm, offering several +abstractions for the programmer. But did you know that Emacs Lisp +comes with a powerful system for object-oriented programming? Join me +for a discussion of EIEIO, and learn how it can help you write more +modular, flexible Emacs Lisp. + +# Discussion + +IRC nick: ieure + +- Q2: AFAIK, EIEIO is generally slower than, e.g. cl-defstructs. When + do you think EIEIO is not suitable for performance reasons? + - A: I agree with Dmitry: first make it work, then make it fast. + I don't think there's a blanket reason not to use EIEIO, but + definitely profile if you're using it in a performance-critical + context. EXWM is one project that uses EIEIO extensively and + seems to perform well, so I don't think it's off-limits for + performance-critical code. +- Q3: Do you have any tips about introspection? e.g. IIRC there's an + EIEIO introspection facility, though it may be somewhat primitive. + - A: It is somewhat primitive, but seems to work okay + (<https://www.gnu.org/software/emacs/manual/html_node/eieio/Introspection.html)>. + I haven't found a need for anything fancier (yet). +- Q4: Have you used any of the EIEIO-related serialization tools? + IIRC there are some limitations with regard to printable/readable + values. + - A: I haven't had call for this, but + <https://www.gnu.org/software/emacs/manual/html_mono/eieio.html#eieio_002dpersistent> + is the mechanism (for anyone wondering) +- Q5: I did not get how generic functions can work with non class + objects + - A: Dynamic dispatch is very powerful! +- Q6:So with that Emacs is on pair with Smalltalk development + environments now (?) + - A: Not very familiar +- Q7: Most of what you presented can be done without `defclass`. + AFAICT, the only exception is *multiple* inheritance (since + `cl-defstruct` also supports single inheritance via `:include`). + - A: Yes, you can mix and match structs/objects or any other + type. You need classes if you want the EIEIO customization + editing facility or MI. I think also `initialize-instance` is + class-only, so you need classes if you have to do some kinds of + complex (cross-slot) initializtaion. + +- I didn't know that custom.el works with EIEIO that way, very nice +- Dang Ian. What a talk, great demos. +- Wow, that's a great talk. +- Great talk. So with that Emacs is on pair with Smalltalk development environments now +- For reference, transient.el, which we all know and love as the engine that drives the magit interface, is written via EIEIO afaik. +- I reckon I should look more into it, I've always avoided it because I was afraid it wouldn't be /quite as nice/ as CLOS or GOOPS. + - ieure: It's missing a few things (most documented in the manual: https://www.gnu.org/software/emacs/manual/html_mono/eieio.html#CLOS-compatibility), but it's solid and worth using. + - Yeah when transient.el first came out I was impressed by how naturally it worked as part of that abstraction. +- ieure: EIEIO all the things! I had to cut it, but you can use dynamic dispatch based on major-mode, like: (cl-defmethod whatever ((mode (derived-mode python-mode)))) and then (whatever major-mode). + +- Also really nice for things like 'window-system. I really like when callsites are clean and not cluttered with conditionals. +- Can eieio do regexp dispatch? + - ieure: Not currently, but it's possible to add. + - okay, so I don't need to feel too bad about coding up my own vtable for those then + - ieure: This is the thing that implements (thing (eql :whatever)) specialization, should be a good starting point if you want (thing (string-match-p "^foo")): <https://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/emacs-lisp/cl-generic.el#n1164> + - thanks for the pointer, but I think I have some more pressing cl-defgeneric reimplementations to make before I touch that + - ieure: Extremely fair. One thing I didn't get to touch on is that you can extend generic functions from anywhere. So you don't have to patch up cl-generic.el, you can define a new method for a generic function defined anywhere, in any file. Which rules. +- This is not a question: Brilliant title for the presentation. :) + +Links: + +- <https://www.gnu.org/software/emacs/manual/html_mono/eieio.html> +# Outline + +- What is EIEIO? +- Why OOP? +- The CLOS Model + - Classes + - Generic Functions + - Methods + - Specialization + - Method Qualifiers + - Multiple Inheritance + - Nice Properties +- Practical Examples + - Encapsulation + - Example: `transmission.el` + - Abstraction + - Example: `sql.el` + - Extensibility + - Example: comint +- Conclusion + + +[[!inline pages="internal(2021/captions/form)" raw="yes"]] + +[[!inline pages="internal(2021/info/form-nav)" raw="yes"]] |