michelf/php-markdown — pull request #143 by s9e (2014-01-17 12:11:52+00:00)
Title: Simplified strong/emphasis regexps

I'm doing research on the Markdown syntax and I was looking through your Markdown library to figure out what was the exact rules with regards to strong/emphasis. While reading the corresponding regular expressions I noticed they were a bit more complicated than necessary.

For instance, the assertion `(?<=\S|^)` means "preceded by not-a-space, or nothing at all". What it really means is "not preceded by a space" which can be expressed as `(?