Use prettify-symbols-mode to enable Iosevka ligatures for GNU Emacs

Recently, I switched back to GNU Emacs from emacs-mac-port¹ for better performance. And there are 3 things that are missing from GNU Emacs but are supported by emacs-mac-port:

1. Font Ligatures
2. Emoji support
3. org-protocol://, mailto:// link handling

This post is a summary for the way I used to enable font ligatures for GNU Emacs, based on the scripts² provided by @mrkgnao.

1. Install haskell if you haven't done it.

   brew cask install haskell-platform
   

2. Run haskell repl

   ghci
   

3. Generate parameters.toml and prettify-symbols-alist for latter Emacs configurations

   :load IosevkaConfigGen
   toToml
   toElisp
   

4. Get/Clone Iosevka³ source code
5. Append the contents in parameters.toml to Iosevka/parameters.toml

6. Install Iosevka's dependencies

   brew install nodejs ttfautohint otfcc-mac64
   

7. Build custom Iosevka

   npm install
   make custom-config
   make custom
   

8. Set prettify-symbols-alist in your Emacs init files

9. Enable prettify-symbols-mode

   (setq prettify-symbols-unprettify-at-point t)
   (global-prettify-symbols-mode +1)