add language_nix (#189)

* add language_nix

* formatting and a tweak to paths

* add string escaping

* add manifest entry

* fix search paths

* remove unnecessary string escaping

* remove entry in README

* simplify comments

2 files changed, 94 insertions, 0 deletions

diff --git a/manifest.json b/manifest.json
index 98aecb8..71143d1 100644
--- a/manifest.json
+++ b/manifest.json
@@ -588,6 +588,13 @@
       "mod_version": "3"
     },
     {
+      "description": "Syntax for the [Nix](https://nixos.wiki/wiki/Overview_of_the_Nix_Language) expression language",
+      "version": "0.1",
+      "path": "plugins/language_nix.lua",
+      "id": "language_nix",
+      "mod_version": "3"
+    },
+    {
       "description": "Syntax for the [Objective C](https://en.wikipedia.org/wiki/Objective-C) programming language",
       "version": "0.1",
       "path": "plugins/language_objc.lua",
diff --git a/plugins/language_nix.lua b/plugins/language_nix.lua
new file mode 100644
index 0000000..149c2fa
--- /dev/null
+++ b/plugins/language_nix.lua
@@ -0,0 +1,87 @@
+-- mod-version:3
+-- https://nixos.wiki/wiki/Overview_of_the_Nix_Language
+local syntax = require "core.syntax"
+
+local function merge_tables(a, b)
+  for _, v in pairs(b) do
+    table.insert(a, v)
+  end
+end
+
+local default_symbols = {
+  ["import"]   = "keyword2",
+  ["with"]     = "keyword2",
+  ["builtins"] = "keyword2",
+  ["inherit"]  = "keyword2",
+  ["assert"]   = "keyword2",
+  ["let"]      = "keyword2",
+  ["in"]       = "keyword2",
+  ["rec"]      = "keyword2",
+  ["if"]       = "keyword",
+  ["else"]     = "keyword",
+  ["then"]     = "keyword",
+  ["true"]     = "literal",
+  ["false"]    = "literal",
+  ["null"]     = "literal",
+}
+
+local default_patterns = {}
+
+local string_interpolation = {
+  { pattern = {"%${", "}"}, type = "keyword2", syntax = {
+    patterns = default_patterns,
+    symbols = default_symbols,
+  }},
+  { pattern = "[%S][%w]*", type = "string" },
+}
+
+merge_tables(default_patterns, {
+  { pattern = "#.*",          type = "comment" },
+  { pattern = {"/%*", "%*/"}, type = "comment" },
+  { pattern = "-?%.?%d+",     type = "number"  },
+
+  -- interpolation
+  { pattern = {"%${", "}"}, type = "keyword2", syntax = {
+    patterns = default_patterns,
+    symbols = default_symbols,
+  }},
+  { pattern = {'"', '"', '\\'}, type = "string", syntax = {
+    patterns = string_interpolation,
+    symbols = {},
+  }},
+  { pattern = {"''", "''"}, type = "string", syntax = {
+    patterns = string_interpolation,
+    symbols = {},
+  }},
+
+  -- operators
+  { pattern = "[%+%-%?!>%*]", type = "operator" },
+  { pattern = "/ ",           type = "operator" },
+  { pattern = "< ",           type = "operator" },
+  { pattern = "//",           type = "operator" },
+  { pattern = "&&",           type = "operator" },
+  { pattern = "%->",          type = "operator" },
+  { pattern = "||",           type = "operator" },
+  { pattern = "==",           type = "operator" },
+  { pattern = "!=",           type = "operator" },
+  { pattern = ">=",           type = "operator" },
+  { pattern = "<=",           type = "operator" },
+
+  -- paths (function because its not used otherwise)
+  { pattern = "%.?%.?/[^%s%[%]%(%){};,:]+", type = "function" },
+  { pattern = "~/[^%s%[%]%(%){};,:]+",      type = "function" },
+  { pattern = {"<", ">"},                   type = "function" },
+
+  -- every other symbol
+  { pattern = "[%a%-%_][%w%-%_]*", type = "symbol" },
+  { pattern = ";%.,:",             type = "normal" },
+})
+
+syntax.add {
+  name = "Nix",
+  files = {"%.nix$"},
+  comment = "#",
+  block_comment = {"/*", "*/"},
+  patterns = default_patterns,
+  symbols = default_symbols,
+}