RelaxNG derivatives vs Earley parsing

Noodling around with the different informal descriptions of Earley parsers reminded me of something that impressed me about 20 years ago. Namely, [1]

There’s a lot in common between James Clark’s algorithm and Earley parsing. In particular, the “dot” notation (a la Wikipedia) 
 (X → α • β, i), consisting of

the production currently being matched (X → α β)
the current position in that production (represented by the dot)
the position i in the input at which the matching of this production began: the origin position
Sounds an awful lot like the description of a derivative:
"The derivative of a pattern p with respect to a node x is a pattern for what's left of p after matching x;"

The portion after the dot IS a derivative, right? Are there subtle differences I’m missing? I’m thinking that Rust, with it’s nice Haskell-like “data class” enums, might be able to adapt some of the logic from [1] to make a very clean, readable implementation.

Welcome any thoughts from those more technically competent, which amounts to pretty much everyone on this list. 
-Joel



[1] https://relaxng.org/jclark/derivative.html <https://relaxng.org/jclark/derivative.html>