Reputation: 835
I'm trying to do my homework and hacking through some example code I saw this line:
[(:+ (:or VAR)) (token-VAR (string->symbol lexeme))]
This is from a lexical analyzer in a calculator;
Now I'm not really sure what either of this does, and I'm not particularly sure what this means exactly, but I'm pretty sure it has what I need to finish my homework. Searching hasn't gotten me any help so all help is great at this time. Thanks!
Upvotes: 2
Views: 172
Reputation: 14035
The sample code probably imported parser-tools
using the :
prefix (which is the recommended prefix in the parser-tools documentation. If that's the case, then :+
means "repetition one or more times" and :or
matches any of the subpatterns (just VAR
in this case).
Upvotes: 9