## 1.1 What is ECL^{i}PS^{e} ?

ECL^{i}PS^{e} (ECL^{i}PS^{e} Common Logic Programming System)
is a Prolog based system whose aim is to serve as a platform
for integrating various Logic Programming extensions, in particular
Constraint Logic Programming (CLP).
The kernel of ECL^{i}PS^{e} is an efficient implementation of standard
(Edinburgh-like) Prolog as described in basic Prolog texts [2].
It is built around an incremental compiler which compiles the ECL^{i}PS^{e}
source into WAM-like code [12], and an emulator of this abstract code.