[sargstuff]

symantics vs. non-semantics. Perhaps examples/explainations of where regular expressions sit relative to grammars, grammar validation, syntax, and parsing might be helpful. [0][1][2][3][4]

[0] : https://web.mit.edu/6.005/www/fa15/classes/17-regex-grammars...

[1] : https://peerj.com/preprints/1248.pdf

[2] : https://www.cs.ox.ac.uk/ralf.hinze/WG2.8/28/slides/fritz-pap...

[3] : https://www.npmjs.com/package/regexp-tree

[4] : example bnf grammar for regular expressions : https://github.com/DmitrySoshnikov/regexp-tree/blob/master/s...