[EXPERIMENT] Create a recursive descent version of KAS' parser

packages/kas/src/__tests__/__snapshots__/lexer.test.ts.snap

@@ -0,0 +1,138 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`lexer should lex LaTeX tokens 1`] = `
+[
+  {
+    "kind": "(",
+  },
+  {
+    "kind": "FRAC",
+  },
+  {
+    "kind": "{",
+  },
+  {
+    "kind": "INT",
+    "value": "1",
+  },
+  {
+    "kind": "}",
+  },
+  {
+    "kind": "{",
+  },
+  {
+    "kind": "VAR",
+    "value": "x",
+  },
+  {
+    "kind": "}",
+  },
+  {
+    "kind": "-",
+  },
+  {
+    "kind": "INT",
+    "value": "1",
+  },
+  {
+    "kind": ")",
+  },
+  {
+    "kind": "EOF",
+  },
+]
+`;
+
+exports[`lexer should lex different numbers 1`] = `
+[
+  {
+    "kind": "INT",
+    "value": "1",
+  },
+  {
+    "kind": "+",
+  },
+  {
+    "kind": "-",
+  },
+  {
+    "kind": "INT",
+    "value": "2",
+  },
+  {
+    "kind": "+",
+  },
+  {
+    "kind": "FLOAT",
+    "value": "3.14",
+  },
+  {
+    "kind": "EOF",
+  },
+]
+`;
+
+exports[`lexer should lex simple tokens 1`] = `
+[
+  {
+    "kind": "INT",
+    "value": "1",
+  },
+  {
+    "kind": "+",
+  },
+  {
+    "kind": "INT",
+    "value": "2",
+  },
+  {
+    "kind": "VAR",
+    "value": "x",
+  },
+  {
+    "kind": "VAR",
+    "value": "y",
+  },
+  {
+    "kind": "EOF",
+  },
+]
+`;
+
+exports[`lexer should lex with options 1`] = `
+[
+  {
+    "kind": "FUNC",
+    "value": "f",
+  },
+  {
+    "kind": "(",
+  },
+  {
+    "kind": "VAR",
+    "value": "x",
+  },
+  {
+    "kind": ")",
+  },
+  {
+    "kind": "SIGN",
+    "value": "=",
+  },
+  {
+    "kind": "CONST",
+    "value": "e",
+  },
+  {
+    "kind": "^",
+  },
+  {
+    "kind": "VAR",
+    "value": "x",
+  },
+  {
+    "kind": "EOF",
+  },
+]
+`;

packages/kas/src/__tests__/lexer.test.ts

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+import {lex} from "../lexer";
+
+describe("lexer", () => {
+    it("should lex simple tokens", () => {
+        const tokens = lex("1+2xy");
+
+        expect(tokens).toMatchSnapshot();
+    });
+
+    it("should lex LaTeX tokens", () => {
+        const tokens = lex("\\left(\\frac{1}{x}\u22121\\right)");
+
+        expect(tokens).toMatchSnapshot();
+    });
+
+    it("should lex different numbers", () => {
+        const tokens = lex("1+-2+3.14");
+
+        expect(tokens).toMatchSnapshot();
+    });
+
+    it("should lex with options", () => {
+        const tokens = lex("f(x)=e^x", {functions: ["f"]});
+
+        expect(tokens).toMatchSnapshot();
+    });
+});