Concepts: Regular expressions

Short essays on the ideas underneath regex — the pieces you read once and keep coming back to when something surprises you. The "ah, that's why" layer beneath the syntax.

Essays in this section

• Understanding the regex engine — backtracking, how a match is actually computed, and why some patterns are dramatically slower than others.
• Why regular expressions — when regex is the right tool, when it isn't, and what the alternatives are.