How does the WordPress URL Routing work? - php

Question

I would like to try and mimic how WordPress has their URL routing system designed, only a much more simplistic level. Can someone help me understand how they have their routing system designed so that I could try and mimic it for my own development.
I see that their routing is set up like this:
Array
(
[sitemap(-+([a-zA-Z0-9_-]+))?\.xml$] => index.php?xml_sitemap=params=$matches[2]
[sitemap(-+([a-zA-Z0-9_-]+))?\.xml\.gz$] => index.php?xml_sitemap=params=$matches[2];zip=true
[sitemap(-+([a-zA-Z0-9_-]+))?\.html$] => index.php?xml_sitemap=params=$matches[2];html=true
[sitemap(-+([a-zA-Z0-9_-]+))?\.html.gz$] => index.php?xml_sitemap=params=$matches[2];html=true;zip=true
[category/(.+?)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?category_name=$matches[1]&feed=$matches[2]
[category/(.+?)/(feed|rdf|rss|rss2|atom)/?$] => index.php?category_name=$matches[1]&feed=$matches[2]
[category/(.+?)/page/?([0-9]{1,})/?$] => index.php?category_name=$matches[1]&paged=$matches[2]
[category/(.+?)/?$] => index.php?category_name=$matches[1]
[tag/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?tag=$matches[1]&feed=$matches[2]
[tag/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?tag=$matches[1]&feed=$matches[2]
[tag/([^/]+)/page/?([0-9]{1,})/?$] => index.php?tag=$matches[1]&paged=$matches[2]
[tag/([^/]+)/?$] => index.php?tag=$matches[1]
[type/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?post_format=$matches[1]&feed=$matches[2]
[type/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?post_format=$matches[1]&feed=$matches[2]
[type/([^/]+)/page/?([0-9]{1,})/?$] => index.php?post_format=$matches[1]&paged=$matches[2]
[type/([^/]+)/?$] => index.php?post_format=$matches[1]
[robots\.txt$] => index.php?robots=1
[.*wp-(atom|rdf|rss|rss2|feed|commentsrss2)\.php$] => index.php?feed=old
[.*wp-app\.php(/.*)?$] => index.php?error=403
[.*wp-register.php$] => index.php?register=true
[feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?&feed=$matches[1]
[(feed|rdf|rss|rss2|atom)/?$] => index.php?&feed=$matches[1]
[page/?([0-9]{1,})/?$] => index.php?&paged=$matches[1]
[comments/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?&feed=$matches[1]&withcomments=1
[comments/(feed|rdf|rss|rss2|atom)/?$] => index.php?&feed=$matches[1]&withcomments=1
[search/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?s=$matches[1]&feed=$matches[2]
[search/(.+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?s=$matches[1]&feed=$matches[2]
[search/(.+)/page/?([0-9]{1,})/?$] => index.php?s=$matches[1]&paged=$matches[2]
[search/(.+)/?$] => index.php?s=$matches[1]
[author/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?author_name=$matches[1]&feed=$matches[2]
[author/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?author_name=$matches[1]&feed=$matches[2]
[author/([^/]+)/page/?([0-9]{1,})/?$] => index.php?author_name=$matches[1]&paged=$matches[2]
[author/([^/]+)/?$] => index.php?author_name=$matches[1]
[([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&day=$matches[3]&feed=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&day=$matches[3]&feed=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/page/?([0-9]{1,})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&day=$matches[3]&paged=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&day=$matches[3]
[([0-9]{4})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&feed=$matches[3]
[([0-9]{4})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&feed=$matches[3]
[([0-9]{4})/([0-9]{1,2})/page/?([0-9]{1,})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&paged=$matches[3]
[([0-9]{4})/([0-9]{1,2})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]
[([0-9]{4})/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&feed=$matches[2]
[([0-9]{4})/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&feed=$matches[2]
[([0-9]{4})/page/?([0-9]{1,})/?$] => index.php?year=$matches[1]&paged=$matches[2]
[([0-9]{4})/?$] => index.php?year=$matches[1]
[[0-9]{4}/[0-9]{1,2}/[^/]+/attachment/([^/]+)/?$] => index.php?attachment=$matches[1]
[[0-9]{4}/[0-9]{1,2}/[^/]+/attachment/([^/]+)/trackback/?$] => index.php?attachment=$matches[1]&tb=1
[[0-9]{4}/[0-9]{1,2}/[^/]+/attachment/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?attachment=$matches[1]&feed=$matches[2]
[[0-9]{4}/[0-9]{1,2}/[^/]+/attachment/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?attachment=$matches[1]&feed=$matches[2]
[[0-9]{4}/[0-9]{1,2}/[^/]+/attachment/([^/]+)/comment-page-([0-9]{1,})/?$] => index.php?attachment=$matches[1]&cpage=$matches[2]
[([0-9]{4})/([0-9]{1,2})/([^/]+)/trackback/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&name=$matches[3]&tb=1
[([0-9]{4})/([0-9]{1,2})/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&name=$matches[3]&feed=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&name=$matches[3]&feed=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([^/]+)/page/?([0-9]{1,})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&name=$matches[3]&paged=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([^/]+)/comment-page-([0-9]{1,})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&name=$matches[3]&cpage=$matches[4]
[([0-9]{4})/([0-9]{1,2})/([^/]+)(/[0-9]+)?/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&name=$matches[3]&page=$matches[4]
[[0-9]{4}/[0-9]{1,2}/[^/]+/([^/]+)/?$] => index.php?attachment=$matches[1]
[[0-9]{4}/[0-9]{1,2}/[^/]+/([^/]+)/trackback/?$] => index.php?attachment=$matches[1]&tb=1
[[0-9]{4}/[0-9]{1,2}/[^/]+/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?attachment=$matches[1]&feed=$matches[2]
[[0-9]{4}/[0-9]{1,2}/[^/]+/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?attachment=$matches[1]&feed=$matches[2]
[[0-9]{4}/[0-9]{1,2}/[^/]+/([^/]+)/comment-page-([0-9]{1,})/?$] => index.php?attachment=$matches[1]&cpage=$matches[2]
[([0-9]{4})/([0-9]{1,2})/comment-page-([0-9]{1,})/?$] => index.php?year=$matches[1]&monthnum=$matches[2]&cpage=$matches[3]
[([0-9]{4})/comment-page-([0-9]{1,})/?$] => index.php?year=$matches[1]&cpage=$matches[2]
[.?.+?/attachment/([^/]+)/?$] => index.php?attachment=$matches[1]
[.?.+?/attachment/([^/]+)/trackback/?$] => index.php?attachment=$matches[1]&tb=1
[.?.+?/attachment/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?attachment=$matches[1]&feed=$matches[2]
[.?.+?/attachment/([^/]+)/(feed|rdf|rss|rss2|atom)/?$] => index.php?attachment=$matches[1]&feed=$matches[2]
[.?.+?/attachment/([^/]+)/comment-page-([0-9]{1,})/?$] => index.php?attachment=$matches[1]&cpage=$matches[2]
[(.?.+?)/trackback/?$] => index.php?pagename=$matches[1]&tb=1
[(.?.+?)/feed/(feed|rdf|rss|rss2|atom)/?$] => index.php?pagename=$matches[1]&feed=$matches[2]
[(.?.+?)/(feed|rdf|rss|rss2|atom)/?$] => index.php?pagename=$matches[1]&feed=$matches[2]
[(.?.+?)/page/?([0-9]{1,})/?$] => index.php?pagename=$matches[1]&paged=$matches[2]
[(.?.+?)/comment-page-([0-9]{1,})/?$] => index.php?pagename=$matches[1]&cpage=$matches[2]
[(.?.+?)(/[0-9]+)?/?$] => index.php?pagename=$matches[1]&page=$matches[2]
)
From there, I am having a tough time following how they physically route all of the traffic through the single index.php file. Conceptually, I understand the commands in the array that setup the URL rewrites and how the .htaccess file works, but I just can't seem to understand how it physically executes the code to pass the parameters through the index.php files.
Anyone have any good tutorials or examples?