@INPROCEEDINGS{BrasselChitilHanusHuch04PADL,
author = "Bra{\ss}el, B. and Chitil, O. and Hanus, M. and Huch, F.",
title = "Observing Functional Logic Computations",
year = "2004",
publisher = "Springer LNCS 3057",
pages = "193-208",
booktitle = "Proc.\ of the Sixth International Symposium on
     Practical Aspects of Declarative Languages (PADL'04)",
abstract = {
A lightweight approach to debugging functional logic programs by observations
is presented, implemented for the language Curry. The Curry Object
Observation System (COOSy) comprises a portable library plus a viewing tool.
A programmer can observe data structures and functions by annotating
expressions in his program.  The possibly partial values of observed
expressions that are computed during program execution are recorded in a trace
file, including information on non-deterministic choices and logical
variables. A separate viewing tool displays the trace content. COOSy covers
all aspects of modern functional logic multiparadigm languages such as lazy
evaluation, higher order functions, non-deterministic search, logical
variables, concurrency and constraints. Both use and implementation of COOSy
are described.
}
}