On Sun, 02 Apr 2017 19:19:11 -0700, lloyd.fo...@gmail.com wrote:
> use Grammar::Tracer;
> grammar G {
> token TOP { <first-fail> || <second-succeed> }
> token first-fail { <thing> '?' }
> token second-succeed { <thing> '!' }
> token thing { "foo" }
> }
> note G.parse("foo!")
>
> #grammar tracer output:
>
> TOP
> | first-fail
> | | thing
> | | * MATCH "foo"
> | * FAIL
> | second-succeed
> | | thing
> | | * MATCH "" # it actually matches it but it's an empty string...
> | * FAIL
> * FAIL
> Nil
>
> If you just create an identical second token and use that instead it works:
>
> grammar G {
> token TOP { <first-fail> || <second-succeed> }
> token first-fail { <thing> '?' }
> token second-succeed { <thing2> '!' }
> token thing { "foo" }
> token thing2 { "foo" }
> }
>
> note G.parse("foo!")
>
> ｢foo!｣
> second-succeed => ｢foo!｣
> thing2 => ｢foo｣
Moved to Grammar::Debugger's ticket queue[^1], since it matches just fine when
the module isn't used.
It has a related ticket about `.parse`ing twice.
https://github.com/jnthn/grammar-debugger/issues/33
