Parser doesn't try the alternative choice if first parser fails

[etsinko]

Parser doesn't try the alternative choice if first parser fails

[jon-hanson]

It's a parser for LL(1) grammars, meaning at every stage the parser only needs to look ahead 1 token (at most) to determine which rule to apply. For your grammar it needs to look 2 characters ahead to decide which of those two rules should apply.

If you rewrite your grammar as something like:

var r = Text.string("A")
        .and(Parser.choice(Text.string("B"), Text.string("C")))
        .map(String::concat)
        .parse(Input.of("AC"));
System.out.println(r.isSuccess());

then it should work.

[etsinko]

Got it! Thanks for the explanation