pub fn dispatch(op: &str, args: &[Value]) -> Option<Result<Value, String>>Expand description
Dispatch an arrow.* builtin call. Returns Some(Result) if the op
was recognised, None if it should fall through to other dispatch
(the caller treats None as “unknown op”).
Kernels whose Lex signature is Result[T, Str] go through lift_result
so a host-side Err(s) becomes a Lex Err("...") Variant, not a
runtime panic. Kernels that return a bare type (nrows :: Table -> Int)
don’t lift — a bad argument there is a programmer error and should
surface as a runtime mismatch.