Error: "template instance ... is not a template declaration, it is a function"

[Matej Nanut]

Hey everyone,

I've gotten that error before but I don't know how I removed it. I don't see
what's wrong, it seems to work most of the time, but not always. I'm sure
there's a reasonable explanation and my understanding of the matter lacks
somewhat. What exactly does it mean?

I'm trying to use "parse!byte(line)", and it reports that error. If I
change it to
"to!byte(line)" it works. How are the "declarations" different?

"line" is a mere string in both cases.

It works fine if I move it into main().

Thank you,
Matej