eval JavaScript code in Markdown text

eval_markdown.js

"use strict";

// eval_markdown.js for node.js
// $ node eval_markdown.js Markdown.md
//
// eval JavaScript code in Markdown text
// from
// ```javascript
// to
// ```

console.log('eval markdown:', process.argv[2]);
eval((function(file_name){
	var fs = require('fs');

	var lines = fs.readFileSync(file_name, {encoding: 'utf-8'}).split("\n")

	var line;
	var js = false;
	var js_code = '';
	for(var num = 0; num < lines.length; num++){
		line = lines[num];

		if (line.match(/^```javascript/)) {
			js = true;
			continue;
		}
		else if (line.match(/^```/)) {
			js = false;
			continue;
		}

		if (js) {
			js_code = js_code + line +
				'   //' + (num + 1) + ': ' +  file_name + '\n';
		}
	}
	return js_code;
})(process.argv[2]));