CONSTANTS and PHP Class Definitions. Using define('MY_VAR', 'default value'). INSIDE a class definition does not work as expected. You have to use the PHP keyword 'const' and initialize it with a scalar value -- boolean, int, float, string (or array in PHP 5.6+) -- right away.
Prepositional Phrases. Do not use a comma between separate phrases unless they are in a series. A comma may also set off a single prepositional phrase at the beginning to make the sentence clear. A comma is recommended after any introductory prepositional phrase of more than four words. Correct: Under the kitchen table the dog cowered. (Single short, clear phrase.
No, the comma is not needed. Although commas are sometimes used to separate adjectives, they are used in that way only in certain circumstances: Use commas to separate two or more coordinate adjectives that describe the same noun. Be sure never to add an extra comma between the final adjective and the noun itself or to use commas with non-coordinate adjectives.