Is there a regular expression to detect a valid regular expression?

Re:Is there a regular expression to detect a valid regular e... by shakna on Monday September 09, 2019 @04:25AM (#20916196)

> So how would you tokenize without the use of regular expressions?

Since this need doesn't appear to be an everyday one, with clearly defined targets, a simple hand-written lexer isn't hard to write, and will make less mistakes than a regex. Just use a scanning approach. As a bonus, you'll still be able to read in 12 months time.

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Re:Is there a regular expression to detect a valid regular e... by unlinkr on Monday September 09, 2019 @04:48AM (#20916309)

Why would a hand-written lexer have fewer mistakes than a regular expression using an off-the-shelf regex engine? They would need to encode the same lexical grammar, so at that level there is the same amount of complexity.

Writing a lexer by hand is just trading ten lines of regex (a widely known declarative DSL) with hundreds of lines of custom code. I don't see how that would be more maintainable in the long run.

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