First stab at adding the Dotenv language

src/components.json

@@ -383,6 +383,10 @@
 			"title": "Docker",
 			"owner": "JustinBeckwith"
 		},
+		"dotenv": {
+			"title": "Dotenv (.env)",
+			"owner": "DmitrySharabin"
+		},
 		"dot": {
 			"title": "DOT (Graphviz)",
 			"owner": "RunDevelopment"

src/languages/dotenv.js

@@ -0,0 +1,98 @@
+/** @type {LanguageProto<'dotenv'>} */
+export default {
+	id: 'dotenv',
+	optional: 'bash',
+	grammar () {
+		/**
+		 * @param {RegExp} prefix
+		 * @returns {Array<GrammarToken>}
+		 */
+		const commonPatterns = prefix => {
+			return [
+				{
+					pattern: RegExp(
+						prefix.source +
+							/(?:-?[1-9]\d*|0)(?:\\.\d+)?(?=\s*\}|\s[^}]+$|\s*$|"$)/.source
+					),
+					alias: 'number',
+				},
+				{
+					pattern: RegExp(prefix.source + /(?:false|true)(?=\s*\}|\s[^}]+$|\s*$)/.source),
+					alias: 'boolean',
+				},
+				{
+					// Ignore leading and trailing whitespace characters
+					pattern: RegExp(prefix.source + /\S[^}]*?\S(?=\s*\})/.source),
+					alias: 'string',
+				},
+			];
+		};
+
+		// Based on https://dotenvx.com/docs/env-file
+		return {
+			'comment':
+				/(?:^|(?<=[\s"'`]))#(?![^\n"'`]*["'`])[^\r\n \t]*(?:[ \t]+[^\r\n \t]+)*[ \t]*/,
+			'keyword': /^export(?=\s)/m,
+			'key': {
+				// Allow bare keys (without values)
+				pattern: /(?<=^[ \t]*)[a-z_]\w*(?=[ \t]*(?:=|$))/im,
+				alias: 'constant',
+			},
+			'value': [
+				{
+					pattern: /(?<==\s*)(?:-?[1-9]\d*|0)(?:\.\d+)?(?=\s*$)/,
+					alias: 'number',
+				},
+				{
+					pattern: /(?<==\s*)(?:false|true)(?=\s*$)/,
+					alias: 'boolean',
+				},
+				{
+					pattern:
+						/(?<==\s*)(?:(['"`])(?:\\[\s\S]|(?!\1)[^\\])*?\1|\S(?:.*?\S)?)(?=\s*$|\s+#.*$)/m,
+					alias: 'string',
+					inside: {
+						'command-substitution': {
+							// Command substitution is disabled in strings enclosed in "'" (single quotes) and "`" (backticks)
+							pattern: /(?<!['`][\s\S]*)\$\(.+\)/,
+							inside: {
+								'command-substitution-punctuation': {
+									pattern: /\$\(|\)/,
+									alias: 'punctuation',
+								},
+								'shell-command': {
+									pattern: /.+/,
+									inside: 'bash',
+								},
+							},
+						},
+						'variable-expansion': {
+							// Variable expansion is disabled in strings enclosed in "'" (single quotes) and "`" (backticks)
+							pattern: /(?<!['`][\s\S]*)\$(?:\{[^{]+\}|[^\s"]+)/,
+							inside: {
+								'variable': /(?<=\$\{|\$)[a-z_]\w*/i,
+								'default-value': commonPatterns(/(?<=(?::-|-)\s*)/),
+								'alternative-value': commonPatterns(/(?<=(?::\+|\+)\s*)/),
+								'variable-expansion-punctuation': {
+									pattern: /\$\{|:-|:\+|[$}+-]/,
+									alias: 'punctuation',
+								},
+							},
+						},
+						'escape-sequence': {
+							pattern: /\\['"`#\\nrt]/,
+							alias: 'char',
+						},
+						'punctuation': /^['"`]|['"`]$/,
+					},
+				},
+			],
+			'assignment-operator': {
+				pattern: /=/,
+				alias: 'operator',
+			},
+		};
+	},
+};
+
+/** @import { GrammarToken, LanguageProto } from '../types.d.ts'; */

tests/languages/dotenv+bash/bash_inclusion.test

@@ -0,0 +1,44 @@
+SHORT_HASH=$(git rev-parse --short HEAD)
+PWD_MESSAGE="Running from $(pwd)"
+DATABASE_URL=postgres://$(whoami)@localhost/my_database
+
+----------------------------------------------------
+
+[
+	["assign-left", ["SHORT_HASH"]],
+	["operator", ["="]],
+	["variable", [
+		["variable", "$("],
+		["function", "git"],
+		" rev-parse ",
+		["parameter", "--short"],
+		" HEAD",
+		["variable", ")"]
+	]],
+
+	["assign-left", ["PWD_MESSAGE"]],
+	["operator", ["="]],
+	["string", [
+		"\"Running from ",
+		["variable", [
+			["variable", "$("],
+			["builtin", "pwd"],
+			["variable", ")"]
+		]],
+		"\""
+	]],
+
+	["assign-left", ["DATABASE_URL"]],
+	["operator", ["="]],
+	"postgres://",
+	["variable", [
+		["variable", "$("],
+		["function", "whoami"],
+		["variable", ")"]
+	]],
+	"@localhost/my_database"
+]
+
+----------------------------------------------------
+
+Check for bash inclusion.

tests/languages/dotenv/command_substitution_feature.test

@@ -0,0 +1,115 @@
+DATE=$(date)
+SHORT_HASH=$(git rev-parse --short HEAD)
+LONG_HASH=`git rev-parse HEAD`
+BUILD_ID="build-$(uuidgen)"
+PWD_MESSAGE="Running from $(pwd)"
+
+DATABASE_URL="postgres://$(whoami)@localhost/my_database"
+WITH_SUBSTITUTION=postgres://$(whoami)@localhost/my_database
+NO_SUBSTITUTION='postgres://$(whoami)@localhost/my_database'
+AND_HERE=`Some text...
+postgres://$(whoami)@localhost/my_database`
+
+----------------------------------------------------
+
+[
+	["key", "DATE"],
+	["assignment-operator", "="],
+	["value", [
+		["command-substitution", [
+			["command-substitution-punctuation", "$("],
+			["shell-command", "date"],
+			["command-substitution-punctuation", ")"]
+		]]
+	]],
+
+	["key", "SHORT_HASH"],
+	["assignment-operator", "="],
+	["value", [
+		["command-substitution", [
+			["command-substitution-punctuation", "$("],
+			["shell-command", "git rev-parse --short HEAD"],
+			["command-substitution-punctuation", ")"]
+		]]
+	]],
+
+	["key", "LONG_HASH"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "`"],
+		"git rev-parse HEAD",
+		["punctuation", "`"]
+	]],
+
+	["key", "BUILD_ID"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "\""],
+		"build-",
+		["command-substitution", [
+			["command-substitution-punctuation", "$("],
+			["shell-command", "uuidgen"],
+			["command-substitution-punctuation", ")"]
+		]],
+		["punctuation", "\""]
+	]],
+
+	["key", "PWD_MESSAGE"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "\""],
+		"Running from ",
+		["command-substitution", [
+			["command-substitution-punctuation", "$("],
+			["shell-command", "pwd"],
+			["command-substitution-punctuation", ")"]
+		]],
+		["punctuation", "\""]
+	]],
+
+	["key", "DATABASE_URL"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "\""],
+		"postgres://",
+		["command-substitution", [
+			["command-substitution-punctuation", "$("],
+			["shell-command", "whoami"],
+			["command-substitution-punctuation", ")"]
+		]],
+		"@localhost/my_database",
+		["punctuation", "\""]
+	]],
+
+	["key", "WITH_SUBSTITUTION"],
+	["assignment-operator", "="],
+	["value", [
+		"postgres://",
+		["command-substitution", [
+			["command-substitution-punctuation", "$("],
+			["shell-command", "whoami"],
+			["command-substitution-punctuation", ")"]
+		]],
+		"@localhost/my_database"
+	]],
+
+	["key", "NO_SUBSTITUTION"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "'"],
+		"postgres://$(whoami)@localhost/my_database",
+		["punctuation", "'"]
+	]],
+
+	["key", "AND_HERE"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "`"],
+		"Some text...\r\npostgres://$(whoami)@localhost/my_database",
+		["punctuation", "`"]
+	]]
+]
+
+----------------------------------------------------
+
+Check for command substitution.

tests/languages/dotenv/comment_feature.test

@@ -0,0 +1,90 @@
+# This is a comment
+
+KEY=VAL # inline comment
+KEY="VAL"# and another one
+KEY='VAL'# and another one
+KEY=`VAL`# and another one
+
+KEY="String with a hash # this is not a comment"
+KEY='String with a hash # this is not a comment'
+KEY=`String with a hash # this is not a comment`
+KEY=VAL# also not a comment
+KEY=Escaped \# hash is not a comment as well
+
+----------------------------------------------------
+
+[
+	["comment", "# This is a comment"],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", ["VAL"]],
+	["comment", "# inline comment"],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "\""],
+		"VAL",
+		["punctuation", "\""]
+	]],
+	["comment", "# and another one"],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "'"],
+		"VAL",
+		["punctuation", "'"]
+	]],
+	["comment", "# and another one"],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "`"],
+		"VAL",
+		["punctuation", "`"]
+	]],
+	["comment", "# and another one"],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "\""],
+		"String with a hash # this is not a comment",
+		["punctuation", "\""]
+	]],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "'"],
+		"String with a hash # this is not a comment",
+		["punctuation", "'"]
+	]],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		["punctuation", "`"],
+		"String with a hash # this is not a comment",
+		["punctuation", "`"]
+	]],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", ["VAL# also not a comment"]],
+
+	["key", "KEY"],
+	["assignment-operator", "="],
+	["value", [
+		"Escaped ",
+		["escape-sequence", "\\#"],
+		" hash is not a comment as well"
+	]]
+]
+
+----------------------------------------------------
+
+Check for comments.

tests/languages/dotenv/export_keyword_feature.test

@@ -0,0 +1,14 @@
+export EXPORTED_VAR=value
+
+----------------------------------------------------
+
+[
+	["keyword", "export"],
+	["key", "EXPORTED_VAR"],
+	["assignment-operator", "="],
+	["value", ["value"]]
+]
+
+----------------------------------------------------
+
+Check for the export keyword.