List manipulation in Turbo Prolog

The present paper is concerned with list processing in Turbo Prolog language. It doesn't claim to be an exhaustive description of operations which can be performed upon lists. Nevertheless adduced programs are most representative, more or less known to specialists in logic programming domain. By means of examples are explained the list manipulation techniques, use of recursion, declarative comparison of predicates, analysis and fix-ation of acceptable prototypes and some problems of predicates' inconsistency. Lists are the basic data structure in Turbo Prolog programs and the most valuable programming technique is recursion. A list is an ordered sequence of arbitrary length of elements. The order of elements in the sequence is essential. In case the order is changed we are having a new list. At the same time the list may be conceived (if desired) at a logical level as a set, going aside the order of elements. The list in Turbo Prolog is a binary structure,i.e. the first argument is the first element, the second is the recursive defined rest of list. Thus the list is represented as [X|Xs], where arguments X and Xs describe the head and the tail correspondingly. Here and than, when it is possible, if X is the list head, then Xs represents the list tail. Recursion allows us to process the elements of list. To avoid an infinite recursion there is a necessity of presence of a constant symbol. This is the empty list, which is presented by [ ]. As the list elements can be anything: constants, variables, and surely structures that contain other lists. The only prerequisite is that all elements in a list must belong to the same type.