Prevent WordPress From Executing Shortcode in Post

shortcode.php

<?php

/**
 * Retrieve the shortcode regular expression for searching.
 *
 * The regular expression combines the shortcode tags in the regular expression
 * in a regex class.
 *
 * The regular expression contains 6 different sub matches to help with parsing.
 *
 * 1 - An extra [ to allow for escaping shortcodes with double [[]]
 * 2 - The shortcode name
 * 3 - The shortcode argument list
 * 4 - The self closing /
 * 5 - The content of a shortcode when it wraps some content.
 * 6 - An extra ] to allow for escaping shortcodes with double [[]]
 *
 * @since 2.5
 * @uses $shortcode_tags
 *
 * @return string The shortcode search regular expression
 */
function get_shortcode_regex() {
	global $shortcode_tags;
	$tagnames = array_keys($shortcode_tags);
	$tagregexp = join( '|', array_map('preg_quote', $tagnames) );

	// WARNING! Do not change this regex without changing do_shortcode_tag() and strip_shortcode_tag()
	// Also, see shortcode_unautop() and shortcode.js.
	return
		  '\\['                              // Opening bracket
		. '(\\[?)'                           // 1: Optional second opening bracket for escaping shortcodes: [[tag]]
		. "($tagregexp)"                     // 2: Shortcode name
		. '(?![\\w-])'                       // Not followed by word character or hyphen
		. '('                                // 3: Unroll the loop: Inside the opening shortcode tag
		.     '[^\\]\\/]*'                   // Not a closing bracket or forward slash
		.     '(?:'
		.         '\\/(?!\\])'               // A forward slash not followed by a closing bracket
		.         '[^\\]\\/]*'               // Not a closing bracket or forward slash
		.     ')*?'
		. ')'
		. '(?:'
		.     '(\\/)'                        // 4: Self closing tag ...
		.     '\\]'                          // ... and closing bracket
		. '|'
		.     '\\]'                          // Closing bracket
		.     '(?:'
		.         '('                        // 5: Unroll the loop: Optionally, anything between the opening and closing shortcode tags
		.             '[^\\[]*+'             // Not an opening bracket
		.             '(?:'
		.                 '\\[(?!\\/\\2\\])' // An opening bracket not followed by the closing shortcode tag
		.                 '[^\\[]*+'         // Not an opening bracket
		.             ')*+'
		.         ')'
		.         '\\[\\/\\2\\]'             // Closing shortcode tag
		.     ')?'
		. ')'
		. '(\\]?)';                          // 6: Optional second closing brocket for escaping shortcodes: [[tag]]
}