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diff --git a/2023/talks/overlay.md b/2023/talks/overlay.md new file mode 100644 index 00000000..c8c6c4fe --- /dev/null +++ b/2023/talks/overlay.md @@ -0,0 +1,111 @@ +[[!meta title="Improving compiler diagnostics with Overlays"]] +[[!meta copyright="Copyright © 2023 Jeff Trull"]] +[[!inline pages="internal(2023/info/overlay-nav)" raw="yes"]] + +<!-- Initially generated with emacsconf-publish-talk-page and then left alone for manual editing --> +<!-- You can manually edit this file to update the abstract, add links, etc. ---> + + +# Improving compiler diagnostics with Overlays +Jeff Trull (he/him) - Pronunciation: rhymes with "hull" and "dull", IRC: jaafar, @jaafar@hachyderm.io + +[[!inline pages="internal(2023/info/overlay-before)" raw="yes"]] + +Overlays are a feature of Emacs that allow changing the +appearance of text while preserving its contents. They play a prominent +role in packages like org-mode, which uses them to hide or reveal custom +properties and display inline images, and magit, which uses them to +highlight diffs. + +The presenter will give a introduction to the features of overlays, +demonstrating how to: + +- Create and use overlays in Emacs Lisp code +- Query locations in an existing buffer to find out what overlays are +present. + +He will then demonstrate a new compilation minor mode for improving the +readability of error messages, using overlays to flexibly reformat portions +of the compiler output under user control. + + +# Discussion + +## Questions and answers + +- Q: How did you draw the underbraces and overbraces? + - A: TikZ, the greatest drawing tool ever :) See + <https://tex.stackexchange.com/a/128096/105203>. I went to some + effort to match up the colors, font, and background to Emacs. I + got quite close, I think. +- Q: You've got a nice sounding keyboard. What kind is it? + - A: Sorry about that. It's an ErgoDox EZ +- Q: Do you find that the "invasive" reformatting interferes with + navigation? + - A: A bit. You can't move your cursor into the not-real buffer + text (indentation). But the original text is still visible, so + that works fine. +- Q: Can you show us the keybindings of your minor map for editing + overlays? + - A: It's C-c - and C-c + but you can change it. +- Q:Your examples were with c++, have you experimented with any other + languages? Oh, thanks for the interesting talk by the way! + - A: Other languages don't have the same unpleasant behavior :) I + say this as a long time fan of C++. But it should be possible! +- Q: Would it be possible to include overlays in the source file + itself. There are some language modes (Rust, for instance) that do + this. + - A: [someone else] Sounds like enriched-mode. [Jeff] I'm not + sure what this question means; it's the error messages that are + the big issue +- Q: What are your plans for tspew in the future? + - A: Better future-proofing and more options for formatting +- Q: What is your repository link <https://github.com/jefftrull> ? + - A: <https://github.com/jefftrull/tspew> +- Q: What IDEs do C++ programmers use? If not emacs? How do they deal +with these error messages? + - A: VSCode is quite popular, as well as CLion and also XCode. I think they simply display the error messages as is. +- Q: Have you tried to use treesitter to parse the output? + - A: I think it wants to parse an entire buffer. If I could write a + grammar for a portion of the text and point it at that, that would be + great. I could have maybe made a tsit grammar if I could have applied it to a small bit of the output + - (not the speaker): ISTM that since you set up the syntax tables to recognize <> as parens/whatever that Emacs should be able to parse the effective lists as sexps, but I'm not an expert on that + - (not the speaker) ye it's true, often you want to select what the root source node type would be an AFAIK you cannot change it + +- Q: "org-mode, which uses them to hide or reveal custom properties" I thought they used buffer-invisibility-spec or something like that + - A: yes that's part of it + - do you know of they also use text properties. org code is usually pretty messy, so I don't know much about it + - A: org has been moving toward text properties but I think there is a flag that will use overlays instead (!). There's some controversy about performance that I will touch on in a bit + - Interesting, does that initiative predate the recent performance improvements by Stefan Monnier? + - A: I think so. They were known to be a problem for some time, but then that happened? +- Q: Did you use, e.g. syntax-ppss to parse the depth using the syntax table? + - A: No I tried to though... maybe there's a better way + +## Notes and discussion + +- The org file containing the presentation is here: + <https://media.emacsconf.org/2023/emacsconf-2023-overlay--improving-compiler-diagnostics-with-overlays--jeff-trull.org> +- Tony Aldon's Reddit post on visibility + <https://www.reddit.com/r/emacs/comments/t1r2wq/have_you_ever_wondered_how_orgmode_toggles_the/> +- Overlay performance (maybe) fixed + <https://www.reddit.com/r/emacs/comments/yg4mvt/the_noverlay_branch_was_merged_to_master_this/> +- I think I might need to change subed-waveform to use text properties instead of overlays or fix something else that I'm doing incorrectly, since the overlays get left behind when I kill text + - A: yeah you have to track them yourself +- Can you put the overlay object in a text property to track it? + - A: I don't think you would mix properties and overlays in that manner. There are overlay search functions; people typically add a property that identifies them as theirs. or you can store references in a list or something +- A: One of my reasons for doing this was frustration and people talking about how great VSCode was and I *knew* that Emacs was a good match for certain kinds of problems people don't even try to solve in IDEs +- A: I actually edited this down I know it's still a lot of detail :) +- This is really good! +- Very impressive! And well explained. Thank you. +- yeah try doing that in VSCode! yeah. +- this is slick! +- i'm not a fan of ligatures, but imho :: just begs for it + - Same, I want to see the actual thing that'll be given to the compiler/interpreter/whatever. +- That was great, showing how relatively easy it is to extend Emacs with features like that. +- From the speaker: yantar92: your help was much appreciated in the weeks I spent putting this together :) + +[[!inline pages="internal(2023/info/overlay-after)" raw="yes"]] + +[[!inline pages="internal(2023/info/overlay-nav)" raw="yes"]] + + |