[WIP] RFC 3: languages

rfcs/0003-languages.md

@@ -0,0 +1,159 @@
+---
+feature: (languages)
+start-date: (2021-04-30)
+author: (Shahrukh Khan)
+related-issues: (None)
+---
+
+# Summary
+[summary]: #summary
+
+This RFC describes how language support is to be implemented in Soxin. This
+breaks down in two areas:
+
+* How languages are defined, i-e how to define the language and its properties
+  i-e its compiler, tools, editor plugins etc. How the user can define the
+  defualt plugins for a language in his editor(s).
+* How the user can select default set of languages and its required tools in
+  his editor, and how to override default settings on the editor.
+
+# Motivation
+[motivation]: #motivation
+
+As Soxin is aimed at providing its users with easy-to-configure software, while
+allowing for great customization, an RFC describing how such an important
+feature integrates with the project was needed.
+
+# Detailed design
+[design]: #detailed-design
+
+## Language definition
+
+Languages would be defined in a module named `soxin.programming.languages`.
+Each language, would be an attribute set in this module:
+
+```
+soxin.programming.languages = {
+  go = { /* ... */ };
+  java = { /* ... */ };
+  python = { /* ... */ };
+}
+```
+## Tools defination
+
+Programming tools will be defined in a module named `soxin.programming.tools`.
+Each tool will be an attribute set in this module.
+
+```
+soxin.programming.tools = {
+  git = { /* ... */ };
+  tmux = { /* ... */ };
+}
+```
+This allows soxin to define its own support for languages and tools, while
+allowing room for user customization as well.
+
+Similar to RFC 2, each programming language must include a key for each editor
+which will support that language.  For instance, it could be a plugin for that
+editor that installs support for that language, plus some extra configuration
+to configure that plugin.
+
+## User interaction
+
+### Globally
+
+Similar to RFC 2, a `soxin.settings.programming.languages` and
+`soxin.settings.programming.tools` option would be introduced to allow the user
+to choose his programming stack. The only permitted values here shall be the
+defined in `config.soxin.programming.<type>`. This option shall be of type
+`Array` of `str`, with apply function which iterate over the array and find
+appropriate language or tool.
+
+### Per-editor
+
+Each editor that supports a language must provide a
+`soxin.programs.<editor-name>.language` and `soxin.programs.<editor-name>.tool`
+option to allow the user to override the programming stack settings per editor.
+These options will default to `config.soxin.settings.programming.<type>`,
+and thus will be of type `attrs`. Similar to RFC 2, they will also have will
+also allow `str` and have an `apply` function that will lookup the theme
+from `config.soxin.programming.<type>` for each option.
+
+# Examples and Interactions
+[examples-and-interactions]: #examples-and-interactions
+
+Here's how one could define a language and a tool implementing only the `neovim`
+editor:
+
+```
+{ pkgs, ... }:
+
+{
+  config.soxin.programming.languages = {
+    go = {
+      neovim = {
+        plugins = [ pkgs.neovim.go ];
+        extraRC = ''
+        '';
+      };
+    };
+
+    config.soxin.programming.tools = {
+      git = {
+        plugins = [ pkgs.neovim.fugitive ];
+        extraRc = ''
+        '';
+      };
+    };
+  };
+}
+```
+
+Here's how this would be implemented on the editor side:
+
+```
+{ config, lib, ... }:
+
+let
+  cfg = config.soxin.programs.neovim;
+  goSupportRc = cfg.programming.languages.go ? "";
+  gitSupportRc = cfg.programming.tools.git ? "";
+  goSupportPlugins = cfg.programming.languages.go.plugins ? [];
+  gitSupportPlugins = cfg.programming.tools.git.plugins ? [];
+{
+  config.program.neovim = lib.mkIf soxin.programs.neovim.enable {
+    enable = true;
+    configure = ''
+      /* Some configuration */
+      ${goSupportRc}
+      ${gitSupportRc}
+    '';
+
+    plugins = [ /* Some plugins */ ] ++ goSupportPlugins ++ gitSupportPlugins;
+  };
+}
+```
+
+The options of the `programs.neovim` have been modified for simplicity's sake.
+
+
+# Examples and Interactions
+[examples-and-interactions]: #examples-and-interactions
+
+
+# Drawbacks
+[drawbacks]: #drawbacks
+
+
+# Alternatives
+[alternatives]: #alternatives
+
+
+# Unresolved questions
+[unresolved]: #unresolved-questions
+
+
+# Future work
+[future]: #future-work
+
+