refactor(parser): create lexer to hold lexing logic (#2)

* refactor(parser): create lexer to hold lexing logic

Create separate class for lexing
Refactor language spec for variables and functions.
Add support for comments.

* refactor: add support for more function features

Add support for spread operators.
Add support for calling prototype functions.

.vscode/launch.json

@@ -0,0 +1,37 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Test Current File",
+      "program": "${relativeFile}",
+      "request": "launch",
+      "runtimeArgs": ["--nolazy", "-r", "ts-node/register/transpile-only"],
+      "skipFiles": ["<node_internals>/**"],
+      "type": "node"
+    },
+    {
+      "name": "Test Extractor",
+      "program": "${workspaceFolder}/test/test_extractor.ts",
+      "request": "launch",
+      "runtimeArgs": ["--nolazy", "-r", "ts-node/register/transpile-only"],
+      "skipFiles": ["<node_internals>/**"],
+      "type": "node"
+    },
+    {
+      "runtimeExecutable": "/usr/local/bin/node",
+      "type": "node",
+      "request": "launch",
+      "name": "Jest Current File",
+      "program": "${workspaceFolder}/node_modules/.bin/jest",
+      "args": ["${fileBasenameNoExtension}", "--config", "jest.config.ts"],
+      "console": "integratedTerminal",
+      "internalConsoleOptions": "neverOpen",
+      "windows": {
+        "program": "${workspaceFolder}/node_modules/jest/bin/jest"
+      }
+    }
+  ]
+}

package.json

@@ -49,7 +49,7 @@
     "clean": "rm -rf build",
     "lint:fix": "eslint . --fix",
     "lint:check": "eslint . || exit 1",
-    "format": "prettier --write '**/*.ts' '**/*.json'",
+    "format": "prettier --write '**/*.ts' '**/*.js' '**/*.json'",
     "prepare": "husky install"
   },
   "engines": {

src/constants.ts

@@ -0,0 +1,3 @@
+export const VARS_PREFIX = '___';
+export const DATA_PARAM_KEY = '___d';
+export const BINDINGS_PARAM_KEY = '___b';

src/engine.ts

@@ -1,3 +1,5 @@
+import { BINDINGS_PARAM_KEY, DATA_PARAM_KEY } from './constants';
+import { JsonTemplateLexer } from './lexer';
 import { JsonTemplateParser } from './parser';
 import { JsonTemplateTranslator } from './translator';
 
@@ -7,9 +9,10 @@ export class JsonTemplateEngine {
     this.fn = JsonTemplateEngine.compile(template);
   }
   private static compile(template: string) {
-    const parser = new JsonTemplateParser(template);
+    const lexer = new JsonTemplateLexer(template);
+    const parser = new JsonTemplateParser(lexer);
     const translator = new JsonTemplateTranslator(parser.parse());
-    return new Function('data', 'bindings', translator.translate());
+    return new Function(DATA_PARAM_KEY, BINDINGS_PARAM_KEY, translator.translate());
   }
 
   evaluate(data: any, bindings: any = {}) {

src/error.ts → src/errors.ts

@@ -1,12 +1,12 @@
-export class JsonTemplateParserError extends Error {
+export class JsonTemplateLexerError extends Error {
   readonly column: number;
   constructor(message: string, column: number) {
     super(message);
     this.column = column;
   }
 }
 
-export class JsosTemplateEngineError extends Error {
+export class JsosTemplateParserError extends Error {
   constructor(message: string) {
     super(message);
   }

src/index.ts

@@ -1,5 +1,7 @@
-export * from './error';
+export * from './constants';
 export * from './engine';
+export * from './errors';
+export * from './lexer';
 export * from './operators';
 export * from './parser';
 export * from './translator';