Quick JS doc rewrite

Author: J-Cake

expression-js/build.js

@@ -43,5 +43,8 @@ export default {
 			main: "./lib.js",
 			typings: "./lib.d.ts"
 		}, null, 4));
+	},
+	async "build:readme.md"(config) {
+		await fs.writeFile(config.out.join('pkg/README.md'), await fs.readFile('./dist.md', {encoding: 'utf8'}));
 	}
 }

expression-js/dist.md

@@ -0,0 +1,46 @@
+# expressions
+
+Parser for the expression language used in the spreadsheet plugin. This document outlines the JavaScript portion of the
+library. For Rust see [the Rust crate](../README.md).
+
+## Quickstart
+
+In order to evaluate expressions, three things must happen;
+
+1. A context object containing a [Data Provider](#Data Provider) must be registered
+2. The list of all functions, variables and operators needs to be defined
+3. The expression needs to be passed into the parser.
+
+## Data Provider
+
+A data provider is an object which converts addresses into values. Addresses are arbitrary text tokens wrapped in
+braces. The provider determines their meaning. [See the `repl.ts`](examples/repl.ts) for a feature-complete REPL.
+
+```typescript
+import * as expr from 'expression';
+
+class Table implements expr.DataSource {
+    query(cx:any, query:string) {
+        // Parse the query however you need to.
+        // For example, the format `column:row`
+
+        return "Hey!";
+    }
+}
+```
+
+## Context
+
+Next you'll need a context object which holds state and variables and acts as an API to the expression engine. You can
+define your own functions, globals and operators here.
+
+```typescript
+import * as assert from 'node:assert';
+import * as expr from 'expression';
+
+const cx = new expr.Context(new Table())
+    .withGlobal("twelve", 12)
+    .withGlobal("print", args => console.log(args));
+
+assert.eq(cx.evaluateStr("twelve") == 12);
+```