Tools

Timing

fugit/1

Time a command

Flow Tracing

flow/1

Trace plain code

flow/3

Trace DCG code

Tools for Long Lists

The basic prolog tools for list manipulation are normally defined to process the list one element at a time. However, when the individual list elements are not of interest, as in the following:

• append,
• length,
• last
• reverse

then it is quicker to process long lists in chunks.

Those primitives are defined here as alternatives to the standard library and operate on chunks up to eight elements at a time. They are intended to be fully bilateral.

Tools related to Iteration

iota/3

iota(Start, Finish, List)

produces a List of integers increasing or decreasing in unit steps from Start to Finish.

in/2

in(Element, List)

is the same as member(Element, List).

in(Element, iota(Start, Finish))

is the same as: iota(Start, Finish, List), member(Element, List).

do/2

These are repeat - fail operations which are only useful for producing side effects Being failure driven, they can be nested.

do(while(Condition), Goals)

do(Goals, while(Condition))