Path implementation in R

I am looking for an existing package that provides pathfinding algorithms for 2d data. I have a regular grid with grades and would like to start with the A * algorithm.

I'm surprised that there doesn't seem to be an R package that tackles such a task (obviously a Google search for "a * in R" algorithm gives very non-specific results).

Does anyone know of an existing package, and if not, can I point out an efficient way to implement the algorithm in R?

Thank!