From b48c5c497620288a08a5c225389231ffaede8f8f Mon Sep 17 00:00:00 2001 From: Profpatsch Date: Sun, 8 Aug 2021 10:50:04 +0200 Subject: feat(users/Profpatsch/blog): Add posts section A new section for my awesome website. Migrates an old blogpost from the github repository. Change-Id: I5fd0c2b2679a1367015fa098e3e787bbc0cdd973 Reviewed-on: https://cl.tvl.fyi/c/depot/+/3293 Tested-by: BuildkiteCI Reviewed-by: Profpatsch --- .../2017-05-04-ligature-emulation-in-emacs.md | 123 +++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 users/Profpatsch/blog/posts/2017-05-04-ligature-emulation-in-emacs.md (limited to 'users/Profpatsch/blog/posts/2017-05-04-ligature-emulation-in-emacs.md') diff --git a/users/Profpatsch/blog/posts/2017-05-04-ligature-emulation-in-emacs.md b/users/Profpatsch/blog/posts/2017-05-04-ligature-emulation-in-emacs.md new file mode 100644 index 000000000000..ba80888badd8 --- /dev/null +++ b/users/Profpatsch/blog/posts/2017-05-04-ligature-emulation-in-emacs.md @@ -0,0 +1,123 @@ +title: Ligature Emulation in Emacs +date: 2017-05-04 + +Monday was (yet another) +[NixOS hackathon][hackathon] at [OpenLab Augsburg][ola]. +[Maximilian][mhuber] was there and to my amazement +he got working ligatures in his Haskell files in Emacs! Ever since Hasklig +updated its format to use ligatures and private Unicode code points a while ago, +the hack I had used in my config stopped working. + +Encouraged by that I decided to take a look on Tuesday. Long story short, I was +able to [get it working in a pretty satisfying way][done]. + +[hackathon]: https://www.meetup.com/Munich-NixOS-Meetup/events/239077247/ +[mhuber]: https://github.com/maximilianhuber +[ola]: https://openlab-augsburg.de +[done]: https://github.com/i-tu/Hasklig/issues/84#issuecomment-298803495 + +What’s left to do is package it into a module and push to melpa. + + +### elisp still sucks, but it’s bearable, sometimes + +I’m the kind of person who, when trying to fix something elisp related, normally +gives up two hours later and three macro calls deep. Yes, homoiconic, +non-lexically-scoped, self-rewriting code is not exactly my fetish. +This time the task and the library (`prettify-symbols-mode`) were simple enough +for that to not happen. + +Some interesting technical trivia: + +- elisp literal character syntax is `?c`. `?\t` is the tab character +- You join characters by `(string c1 c2 c3 ...)` +- [dash.el][dash] is pretty awesome and does what a functional programmer + expects. Also, Rainbow Dash. +- Hasklig and FiraCode multi-column symbols actually [only occupy one column, on + the far right of the glyph][glyph]. `my-correct-symbol-bounds` fixes emacs’ + rendering in that case. + + +[dash]: https://github.com/magnars/dash.el +[glyph]: https://github.com/tonsky/FiraCode/issues/211#issuecomment-239082368 + + +## Appendix A + +For reference, here’s the complete code as it stands now. Feel free to paste +into your config; let’s make it [MIT][mit]. Maybe link to this site, in case there are +updates. + +[mit]: https://opensource.org/licenses/MIT + +```elisp + (defun my-correct-symbol-bounds (pretty-alist) + "Prepend a TAB character to each symbol in this alist, +this way compose-region called by prettify-symbols-mode +will use the correct width of the symbols +instead of the width measured by char-width." + (mapcar (lambda (el) + (setcdr el (string ?\t (cdr el))) + el) + pretty-alist)) + + (defun my-ligature-list (ligatures codepoint-start) + "Create an alist of strings to replace with +codepoints starting from codepoint-start." + (let ((codepoints (-iterate '1+ codepoint-start (length ligatures)))) + (-zip-pair ligatures codepoints))) + + ; list can be found at https://github.com/i-tu/Hasklig/blob/master/GlyphOrderAndAliasDB#L1588 + (setq my-hasklig-ligatures + (let* ((ligs '("&&" "***" "*>" "\\\\" "||" "|>" "::" + "==" "===" "==>" "=>" "=<<" "!!" ">>" + ">>=" ">>>" ">>-" ">-" "->" "-<" "-<<" + "<*" "<*>" "<|" "<|>" "<$>" "<>" "<-" + "<<" "<<<" "<+>" ".." "..." "++" "+++" + "/=" ":::" ">=>" "->>" "<=>" "<=<" "<->"))) + (my-correct-symbol-bounds (my-ligature-list ligs #Xe100)))) + + ;; nice glyphs for haskell with hasklig + (defun my-set-hasklig-ligatures () + "Add hasklig ligatures for use with prettify-symbols-mode." + (setq prettify-symbols-alist + (append my-hasklig-ligatures prettify-symbols-alist)) + (prettify-symbols-mode)) + + (add-hook 'haskell-mode-hook 'my-set-hasklig-ligatures) +``` + +## Appendix B (Update 1): FiraCode integration + +I also created a mapping for [FiraCode][fira]. You need to grab the [additional +symbol font][symbol] that adds (most) ligatures to the unicode private use area. +Consult your system documentation on how to add it to your font cache. +Next add `"Fira Code"` and `"Fira Code Symbol"` to your font preferences. Symbol +only contains the additional characters, so you need both. + +If you are on NixOS, the font package should be on the main branch shortly, [I +added a package][symbol-pkg]. + +[fira]: https://github.com/tonsky/FiraCode/ +[symbol]: https://github.com/tonsky/FiraCode/issues/211#issuecomment-239058632 +[symbol-pkg]: https://github.com/NixOS/nixpkgs/pull/25517 + +Here’s the mapping adjusted for FiraCode: + +```elisp + (setq my-fira-code-ligatures + (let* ((ligs '("www" "**" "***" "**/" "*>" "*/" "\\\\" "\\\\\\" + "{-" "[]" "::" ":::" ":=" "!!" "!=" "!==" "-}" + "--" "---" "-->" "->" "->>" "-<" "-<<" "-~" + "#{" "#[" "##" "###" "####" "#(" "#?" "#_" "#_(" + ".-" ".=" ".." "..<" "..." "?=" "??" ";;" "/*" + "/**" "/=" "/==" "/>" "//" "///" "&&" "||" "||=" + "|=" "|>" "^=" "$>" "++" "+++" "+>" "=:=" "==" + "===" "==>" "=>" "=>>" "<=" "=<<" "=/=" ">-" ">=" + ">=>" ">>" ">>-" ">>=" ">>>" "<*" "<*>" "<|" "<|>" + "<$" "<$>" "