Literal tokens beginning with @ fail?

[nkcmr]

I am trying to use this library to try to create a Go parser of Turtle. One of the productions of Turtle is a line that literally begins with @prefix (here).

When I try to create a parser that specifies that the "@prefix" token starts the line, it just doesn't work in Participle. I've condensed this issue into a small, runnable snippet here: https://go.dev/play/p/kOQ2_bAA2Re

This snippet builds 2 parsers:

GRAMMAR (broken):
ProgramBroken = WordBroken* .
WordBroken = "@word" <string> ";" .

GRAMMAR (ok):
ProgramOK = WordOK* .
WordOK = "word" <string> ";" .

The one that makes use of the @ symbol does not seem to work, but when the grammar does not use the @ symbol, it works fine.

I apologize if I have missed something obvious in the documentation, but I did scan around for a few hours to try to get past this issue to no avail. Please let me know if any other info helps, and obviously: thank you so much for this library and your time.

[alecthomas]

@ and word are two separate tokens, so you'll need to match them separately like "@" "word"

[nkcmr]

That does seem to get some things to work. But then it allows for things like @ word "bar", or @\n\n word "foo"; which, applying back to my use-case of trying to implement a Turtle parser, is invalid.

[alecthomas]

If you need it to be a single token containing @<word>, the solution is to define a custom lexer that captures the entire token.