GBNF "regex" character range e.g. [a-z]{min, max} #5369
Description
Prerequisites
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- I am running the latest code. Development is very rapid so there are no tagged versions as of now.
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Feature Description
The grammar is great but I have to manually write out code for strings of minimum and maximum length. I can do them via:
Alpha ::= [a-z]
String ::= Alpha Alpha Alpha Alpha? Alpha?
To make an alphabetic string minimum length 3, maximum length 5. I would like to be able to do:
String ::= [a-z]{3,5}
Alternate syntax:
String ::= [a-z]{5}
For a five-character string.
Motivation
GBNF is already inspired by regex and It's already possible to do this without this enhancement so it is not a critical feature. It would just make the grammar more concise and easier to write. This change wouldn't break any existing grammars.
Possible Implementation
It seems possible to just expand the tokens out like my first example, but I don't know how easy that actually is.