A Functional Logic Language Based on Higher Order Narrowing

Functional logic languageshave a syntax like a purely functional language but use narrowing as operational semantics. We present the functional logic language Higher Order Babel which provides higher order unification for parameter passing and solving equations. When searching for a function which solves an equation “polynomial functions” as well as defined functions are taken into account. In contrast to all other programming languages with higher order unification HO-Babel replaces the expensive β-reduction by the more efficient combinator reduction. Further, HO-Babel is more homogeneous since it does not distinguish functions which only represent data structures and defined function which have access to the full execution mechanismof the language.