CODEWITHSUNDEEP
antlr4
Alice Oualouest
Alice Oualouest

Reputation: 918

Can this grammar be parsed using antlr4?

Given a set S of n rules, I need an antlr4 rule to match any of S subset, in any order :

Example :

Given S = {a,b}, (n = 2) the rule must match

while "a b b", for instance must not match.

It is possible to parse such expression with an antlr4 grammar ? My real set has n = 6, so listing all combinations in the grammar seems not to be a possible choice !

Upvotes: 1

Views: 125

Answers (1)

Bart Kiers
Bart Kiers

Reputation: 170308

No, you can't define combinations and/or permutations of rules in ANTLR (or any other parser generator that I know).

You could use predicates to accomplish your goal, but that means adding target specific code to your grammar: I'd just parse any a or b and validate the structure after parsing (in a custom visitor/listener).

Upvotes: 2

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