Abstract: Embodiments directed to conditionally executing regular expressions and to simplifying regular expressions by canonicalizing regular expression terms. In an embodiment, a computer system accesses identified regular expression key terms that are to appear in a selected portion of text. The regular expression key terms are identified from terms in a selected regular expression. The computer system determines whether the identified regular expression key terms appear in the selected portion of text. The computer system also, upon determining that none of the identified regular expression key terms appears in the selected portion of text, prevents execution of the regular expression. Upon determining that at least one of the identified regular expression key terms appears in the selected portion of text, the computer system executes the regular expression.