  By resorting to the Fock--Bargmann representation, we incorporate the quantum
Weyl--Heisenberg ($q$-WH) algebra into the theory of entire analytic functions.
The main tool is the realization of the $q$--WH algebra in terms of finite
difference operators. The physical relevance of our study relies on the fact
that coherent states (CS) are indeed formulated in the space of entire analytic
functions where they can be rigorously expressed in terms of theta functions on
the von Neumann lattice. The r\^ole played by the finite difference operators
and the relevance of the lattice structure in the completeness of the CS system
suggest that the $q$--deformation of the WH algebra is an essential tool in the
physics of discretized (periodic) systems. In this latter context we define a
quantum mechanics formalism for lattice systems.
