feat(syntax): add support for Haskell (#360)

Author: carlwr

packages/catppuccin-vsc/src/theme/semanticTokens.ts

@@ -34,6 +34,12 @@ export const getSemanticTokens = (context: ThemeContext): SemanticTokens => {
     "type.defaultLibrary:go": { foreground: palette.mauve },
     "variable.readonly.defaultLibrary:go": { foreground: palette.mauve },
 
+    // Haskell:
+    "enumMember:haskell": { foreground: palette.blue }, // data constructor
+    "enum:haskell": { foreground: palette.yellow }, // type constructor
+    "class:haskell": { foreground: palette.yellow, fontStyle: "" }, // typeclass
+    "interface:haskell": { foreground: palette.pink }, // type family
+
     // TOML syntax
     tomlArrayKey: { foreground: palette.blue, fontStyle: "" },
     tomlTableKey: { foreground: palette.blue, fontStyle: "" },

packages/catppuccin-vsc/src/theme/tokens/haskell.ts

@@ -0,0 +1,94 @@
+import type { TextmateColors, ThemeContext } from "@/types";
+
+const tokens = (context: ThemeContext): TextmateColors => {
+  const { palette } = context;
+
+  /*
+  should preferrably appear visually distinct:
+  - data constructors -> use blue
+  - type constructors -> use yellow+italic
+  - typeclasses       -> use yellow
+  */
+
+  return [
+    {
+      name: "data constructors",
+      scope: [
+        "variable.other.enummember",
+        "meta.declaration.data constant.other",
+        "constant.other",
+      ],
+      settings: { foreground: palette.blue },
+      // like functions (capitalized -> still visually distinct)
+    },
+    {
+      name: "type constructors",
+      scope: ["entity.name.type", "storage.type"],
+      settings: {
+        foreground: palette.yellow,
+        fontStyle: "italic",
+      },
+    },
+    {
+      name: "typeclasses",
+      scope: ["entity.name.type.class"],
+      settings: {
+        foreground: palette.yellow,
+        fontStyle: "",
+      },
+    },
+    {
+      name: "module name",
+      scope: "meta.declaration.module.haskell entity.name.namespace.haskell",
+      settings: {
+        foreground: palette.peach, // as in Rust
+      },
+    },
+    {
+      name: "imports",
+      scope: ["entity.name.namespace"],
+      settings: { foreground: palette.rosewater },
+    },
+    {
+      name: "type parameters",
+      scope: ["entity.name.type.parameter", "variable.other.generic-type"],
+      settings: { foreground: palette.maroon },
+    },
+    {
+      name: "pragma keywords",
+      scope: ["	keyword.other.preprocessor"],
+      settings: { foreground: palette.red },
+    },
+    {
+      name: "pragma arguments",
+      scope: ["	keyword.other.preprocessor.extension"],
+      settings: { foreground: palette.peach },
+    },
+    {
+      name: "preprocessor directives",
+      scope: ["meta.preprocessor"],
+      settings: { foreground: palette.rosewater },
+    },
+
+    {
+      name: "type families",
+      scope: ["entity.name.type.interface"],
+      settings: { foreground: palette.pink },
+      // we need something distinct from typeclasses
+      // -> pick pink which is used for meta-variables in Rust
+    },
+    {
+      name: "getters in data constructors/records",
+      scope: ["variable.other.property", "variable.other.member"],
+      settings: { foreground: palette.blue },
+    },
+    {
+      name: "fix else keyword",
+      scope: ["keyword.control.else.haskell"],
+      settings: { foreground: palette.mauve },
+      // catppuccin default sets to yellow considering it preprocessor-like, which it is not for Haskell
+    },
+  ];
+};
+
+export default tokens;

packages/catppuccin-vsc/src/theme/tokens/index.ts

@@ -9,6 +9,7 @@ import dotenv from "./dotenv";
 import gdscript from "./gdscript";
 import golang from "./golang";
 import graphql from "./graphql";
+import haskell from "./haskell";
 import html from "./html";
 import java from "./java";
 import javascript from "./javascript";
@@ -296,6 +297,7 @@ export default function tokens(context: ThemeContext): TextmateColors {
       gdscript,
       golang,
       graphql,
+      haskell,
       html,
       java,
       javascript,