4 ms·

Regexes are at least useful for parsing numbers and symbols. But yeah, that shouldn't be where you get stuck.

• macintux 6y ago
  [\s,](~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])"?|;.|[^\s\[\]{}('"`,;)]) Step 0, so I didn't get very far. https://github.com/kanaka/mal/blob/master/process/guide.md#step0 https://github.com/kanaka/mal/blob/master/process/guide.md#s...
  • cellularmitosis 6y ago
    Whoa that regex is a monster. Try starting with simpler pieces and see if you get further this time around. Good luck! https://gist.github.com/cellularmitosis/75dc4aefe88438c14e9433f8728342d1 https://gist.github.com/cellularmitosis/75dc4aefe88438c14e94...
  • the-smug-one 5y ago
    Well, you certainly don't need that regex to implement a Lisp.
  • kanaka 5y ago
    It's a long regex, but it's just whitespace followed by an alternation with 5 different types of data: split-unquote, special characters, strings, comments, symbols. The string tokenizing branch is a bit complicated because it has to allow internal escaping of quotes. Early iterations of the guide didn't explain the regex in detail but the section now describes each of the regex components. There are online tools to help visualize regex's. Here is a recent tweet including a visualization of mal's tokenizer regex: https://twitter.com/Mehulwastaken/status/1382292764834996230 https://twitter.com/Mehulwastaken/status/1382292764834996230