Implementation of the LR(k,inf) parser described in Szymanski's thesis, 1973.

Interpreter; obtains grammar and input as C code.

Szymanski writes: "all our parsing methods degenerate to the LR(0)
method when this value (i.e. 0) is chosen for k." (page 43), but the
algorithm does not.  An attempt to remedy this gracefully has been
made, trying to modify the algorithm as little as possible.

Left recursion not implemented.

It should be relatively easy to add LR(k,t) to it, but that has not
been implemented.