2.1 library(pengines): Pengines: Web Logic Programming Made Easy
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Availability::- use_module(library(pengines)).
Source[semidet,multifile]prepare_goal(+Goal0, -Goal1, +Options)
Pre-preparation hook for running Goal0. The hook runs in the context of the pengine. Goal is the raw goal given to ask. The returned Goal1 is subject to goal expansion (expand_goal/2) and sandbox validation (safe_goal/1) prior to execution. If this goal fails, Goal0 is used for further processing.
Options provides the options as given to ask