add babel macro support

README.md

@@ -1,4 +1,5 @@
 # [nearley](http://nearley.js.org) ↗️
+## With added macro support!
 [![JS.ORG](https://img.shields.io/badge/js.org-nearley-ffb400.svg?style=flat-square)](http://js.org)
 [![npm version](https://badge.fury.io/js/nearley.svg)](https://badge.fury.io/js/nearley)
 

lib/nearley.js

@@ -384,7 +384,7 @@
     return {
         Parser: Parser,
         Grammar: Grammar,
-        Rule: Rule,
+        Rule: Rule
     };
 
 }));

macro.js

@@ -0,0 +1,50 @@
+const { createMacro } = require('babel-plugin-macros');
+const { exec } = require('child_process');
+const nearley = require('./lib/nearley.js');
+const lint = require('./lib/lint.js');
+const generate = require('./lib/generate.js');
+const Compile = require('./lib/compile.js');
+const { version } = require('./package.json');
+const opts = require('commander');
+const fs = require('fs');
+const { dirname, resolve } = require('path');
+
+let hurl = (why) => {throw why};
+
+
+module.exports = createMacro(({references, babel, state: {file: {opts: {filename}}}}) => {
+  references.default.map(({ parentPath: path}) => {
+    path.isCallExpression() || hurl('used as non-call expression');
+
+    const grammar = path.get("arguments.0");
+
+    grammar.isStringLiteral() || hurl('first argument not string');
+
+    const grammarFile = grammar.evaluate().value;
+
+    const parser = new nearley.Parser(nearley.Grammar.fromCompiled(
+      require('./lib/nearley-language-bootstrapped.js')
+    ));
+
+
+    opts._name="fake";
+    // emulation of bin/nearleyc
+    opts.version(version, '-v, --version')
+      .arguments('<file.ne>')
+      .option('-o, --out [filename.js]', 'File to output to (defaults to stdout)', false)
+      .option('-e, --export [name]', 'Variable to set parser to', 'grammar')
+      .option('-q, --quiet', 'Suppress linter')
+      .option('--nojs', 'Do not compile postprocessors')
+      // hack to allow us to parse custom params
+      .parse(["fake", "fake", grammarFile])
+
+    parser.feed('\n');
+    parser.feed(fs.readFileSync(resolve(dirname(filename), grammarFile)));
+    const c = Compile(
+      parser.results[0],
+      Object.assign({version}, opts)
+    );
+
+    path.replaceWithSourceString(`(()=>{${generate(c,  opts.export)}})()`);
+  })
+})