Optional Token in parser

[afonso360]

Would it be possible to add support for an optional token in the parser?

I'm trying to implement a parser that allows me to parse a language with an optional semicolon. If this is already implemented it probably should be documented.

[goffrie]

It should work to do this:

optionalSemicolon: () {
    => (),
    Semicolon => (),
}
...
manyStatements: ... {
    => ...
    manyStatements[sts] statement[st] optionalSemicolon => ...
}

Here's an example for demo.rs: https://gist.github.com/goffrie/2dacbe5aefe7e4ea83d4b4da876ef39e

If you're asking for a convenient shorthand (like Semicolon? instead of adding a new nonterminal), then that's a valid feature request.

[afonso360]

Sorry, didn't realize that I could do that.

The shorthand would be awesome tho!

[maxrdz]

It should work to do this:

optionalSemicolon: () {

    => (),

    Semicolon => (),

}

...

manyStatements: ... {

    => ...

    manyStatements[sts] statement[st] optionalSemicolon => ...

}

Here's an example for demo.rs: https://gist.github.com/goffrie/2dacbe5aefe7e4ea83d4b4da876ef39e

If you're asking for a convenient shorthand (like Semicolon? instead of adding a new nonterminal), then that's a valid feature request.

Correct me if i'm wrong, but I believe this causes a shift-reduce conflict?