Add VS Code extension.

.codespellrc

@@ -1,2 +1,3 @@
 [codespell]
 ignore-words-list = upto,nd,ba,doas,fo,struc,shouldbe,iterm,lates,testof
+skip = ./vscode/node_modules

.gitignore

@@ -21,8 +21,6 @@ _testmain.go
 
 *.exe
 
-/.vscode/
-
 # Project specific
 cover
 /_bin/

.vscode/launch.json

@@ -0,0 +1,13 @@
+{
+	"version": "0.2.0",
+	"configurations": [
+		{
+			"name": "Run Extension",
+			"type": "extensionHost",
+			"request": "launch",
+			"args": [
+				"--extensionDevelopmentPath=${workspaceFolder}"
+			],
+		}
+	]
+}

vscode/.gitignore

@@ -0,0 +1,2 @@
+/node_modules
+/*.vsix

vscode/HACKING.md

@@ -0,0 +1,12 @@
+# Developing the Visual Studio Code extension
+
+Follow these steps to run the extension from source:
+
+1.  Install NPM dependencies: `npm install`.
+
+2.  Open the repository root (**not** this directory) in VS Code, and choose
+    "Run Extension" from the
+    [debug side bar](https://code.visualstudio.com/docs/editor/debugging).
+
+See Visual Studio Code's documentation on
+[developing language extensions](https://code.visualstudio.com/api/language-extensions/overview).

vscode/README.md

@@ -0,0 +1,11 @@
+# Elvish for Visual Studio Code
+
+This extension provides support for [Elvish](https://elv.sh) in
+[Visual Studio Code](https://code.visualstudio.com).
+
+Current functionalities:
+
+-   Syntax highlighting and configuration (e.g. bracket pairs)
+
+-   Error checking and basic autocompletion, using Elvish's builtin language
+    server

vscode/elvish.tmLanguage.json

@@ -0,0 +1,117 @@
+{
+	"$schema": "https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json",
+	"name": "Elvish",
+	"scopeName": "source.elvish",
+	"fileTypes": [
+		"elv"
+	],
+	"patterns": [
+		{
+			"name": "string.quoted.double.elvish",
+			"begin": "\"",
+			"end": "\"",
+			"patterns": [
+				{
+					"name": "constant.character.escape.elvish",
+					"match": "\\\\."
+				}
+			]
+		},
+		{
+			"name": "string.quoted.single.elvish",
+			"begin": "'",
+			"end": "'"
+		},
+
+		{
+			"name": "comment.line.number-sign.elvish",
+			"begin": "#",
+			"end": "$"
+		},
+
+		{
+			"name": "variable.other.elvish",
+			"match": "\\$[\\w\\d_:~-]+"
+		},
+		{
+			"match": "(?<=^|\\{ |\\{\t|\\(|\\||\\;)\\s*(var|set|tmp|del)((\\s+[\\w\\d_:~-]+)*)",
+			"captures": {
+				"1": {
+					"name": "keyword.other.elvish"
+				},
+				"2": {
+					"name": "variable.other.elvish"
+				}
+			}
+		},
+		{
+			"match": "(?<=^|\\{ |\\{\t|\\(|\\||\\;)\\s*(for)\\s+([\\w\\d_:~-]+)",
+			"captures": {
+				"1": {
+					"name": "keyword.control.elvish"
+				},
+				"2": {
+					"name": "variable.other.elvish"
+				}
+			}
+		},
+		{
+			"match": "}\\s+(catch|except)\\s+([\\w\\d_:~-]+)",
+			"captures": {
+				"1": {
+					"name": "keyword.control.elvish"
+				},
+				"2": {
+					"name": "variable.other.elvish"
+				}
+			}
+		},
+
+		{
+			"match": "(?<=^|\\{ |\\{\t|\\(|\\||\\;)\\s*(nop|!=|!=s|%|\\*|\\+|-gc|-ifaddrs|-log|-override-wcwidth|-stack|-|/|<|<=|<=s|<s|==|==s|>|>=|>=s|>s|all|assoc|base|bool|break|call|cd|compare|constantly|continue|count|defer|deprecate|dissoc|drop|each|eawk|echo|eq|eval|exact-num|exec|exit|external|fail|fg|float64|from-json|from-lines|from-terminated|get-env|has-env|has-external|has-key|has-value|is|keys|kind-of|make-map|multi-error|nop|not-eq|not|ns|num|one|only-bytes|only-values|order|peach|pprint|print|printf|put|rand|randint|range|read-line|read-upto|repeat|repr|resolve|return|run-parallel|search-external|set-env|show|sleep|slurp|src|styled|styled-segment|take|tilde-abbr|time|to-json|to-lines|to-string|to-terminated|unset-env|use-mod|wcswidth)(?=[\\s)}<>;|&])",
+			"captures": {
+				"1": {
+					"name": "support.function"
+				}
+			}
+		},
+
+		{
+			"match": "(?<=^|\\{ |\\{\t|\\(|\\||\\;)\\s*(and|or|coalesce)(?=[\\s)}<>;|&])",
+			"captures": {
+				"1": {
+					"name": "keyword.operator.elvish"
+				}
+			}
+		},
+		{
+			"match": "(?<=^|\\{ |\\{\t|\\(|\\||\\;)\\s*(use|var|set|tmp|del|pragma|fn)(?=[\\s)}<>;|&])",
+			"captures": {
+				"1": {
+					"name": "keyword.other.elvish"
+				}
+			}
+		},
+		{
+			"match": "(?<=^|\\{ |\\{\t|\\(|\\||\\;)\\s*(while|for|try|if)(?=[\\s)}<>;|&])",
+			"captures": {
+				"1": {
+					"name": "keyword.control.elvish"
+				}
+			}
+		},
+		{
+			"match": "}\\s+(elif|else|finally)\\s+([\\w\\d_:~-]+)",
+			"captures": {
+				"1": {
+					"name": "keyword.control.elvish"
+				}
+			}
+		},
+
+		{
+			"name": "keyword.operator.elvish",
+			"match": "[*?|&;<>()\\[\\]{}]"
+		}
+	]
+}

vscode/extension.js

@@ -0,0 +1,24 @@
+const { LanguageClient } = require("vscode-languageclient/node");
+
+let client;
+
+function activate() {
+    client = new LanguageClient(
+        "elvish",
+        "Elvish Language Server",
+        { command: "elvish", args: ["-lsp"] },
+        { documentSelector: [{ scheme: "file", language: "elvish" }] }
+    );
+    client.start();
+}
+
+function deactivate() {
+    if (client) {
+        return client.stop();
+    }
+}
+
+module.exports = {
+    activate,
+    deactivate,
+};

vscode/language-configuration.json

@@ -0,0 +1,24 @@
+{
+    "comments": {
+        "lineComment": "#",
+    },
+    "brackets": [
+        ["{", "}"],
+        ["[", "]"],
+        ["(", ")"]
+    ],
+    "autoClosingPairs": [
+        ["{", "}"],
+        ["[", "]"],
+        ["(", ")"],
+        ["\"", "\""],
+        ["'", "'"]
+    ],
+    "surroundingPairs": [
+        ["{", "}"],
+        ["[", "]"],
+        ["(", ")"],
+        ["\"", "\""],
+        ["'", "'"]
+    ]
+}

vscode/package-lock.json

@@ -0,0 +1,192 @@
+{
+    "name": "elvish",
+    "version": "0.19.0",
+    "lockfileVersion": 2,
+    "requires": true,
+    "packages": {
+        "": {
+            "name": "elvish",
+            "version": "0.19.0",
+            "dependencies": {
+                "vscode-languageclient": "^7.0.0"
+            },
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+            }
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+        },
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+        }
+    }
+}

vscode/package.json

@@ -0,0 +1,56 @@
+{
+    "name": "elvish",
+    "displayName": "Elvish",
+    "description": "Elvish language support for Visual Studio Code",
+    "version": "0.1.0",
+    "publisher": "elves",
+    "license": "BSD-2-Clause",
+    "icon": "icon.png",
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/elves/elvish"
+    },
+    "engines": {
+        "vscode": "^1.65.0"
+    },
+    "categories": [
+        "Programming Languages"
+    ],
+    "activationEvents": [
+        "onLanguage:elvish"
+    ],
+    "main": "./extension.js",
+    "contributes": {
+        "languages": [{
+            "id": "elvish",
+            "aliases": ["Elvish", "elvish"],
+            "extensions": [".elv"],
+            "configuration": "./language-configuration.json"
+        }],
+        "grammars": [{
+            "language": "elvish",
+            "scopeName": "source.elvish",
+            "path": "./elvish.tmLanguage.json"
+        }],
+        "configuration": {
+            "title": "Elvish",
+            "properties": {
+                "elvish.trace.server": {
+                    "type": "string",
+                    "enum": [
+                        "off",
+                        "messages",
+                        "verbose"
+                    ],
+                    "default": "off",
+                    "description": "Trace communication between VS Code and the Elvish language server. Trace messages are shown in the Elvish Language Server output channel."
+                }
+            }
+        }
+    },
+	"scripts": {
+	},
+    "dependencies": {
+        "vscode-languageclient": "^7.0.0"
+    }
+}