Miscellaneous ISO Prolog predicates
Author(s): Daniel Cabeza.
This module implements some miscellaneous ISO Prolog predicates.
Usage and interface
- Library usage:
:- use_module(library(iso_misc)). - Exports:
- Predicates:
once/1, compound/1, sub_atom/5, unify_with_occurs_check/2.
- Predicates:
- Imports:
- System library modules:
between. - Packages:
prelude, nonpure, assertions, isomodes.
- System library modules:
Documentation on exports
PREDICATE
once(G)
Finds the first solution of goal G (if any). once/1 behaves as call/1, except that no further solutions are explored on backtracking.
Usage:ISO
- The following properties should hold at call time:
(basic_props:callable/1)G is a term which represents a goal, i.e., an atom or a structure.
PREDICATE
compound(T)
T is currently instantiated to a compound term.
Usage:ISO
- Call and exit should be compatible with:
(basic_props:term/1)T is any term. - The following properties should hold upon exit:
(basic_props:term/1)T is any term.
(basic_props:struct/1)T is a compound term.
PREDICATE
sub_atom(Atom,Before,Length,After,Sub_atom)
Is true iff atom Atom can be broken into three pieces, AtomL, Sub_atom and AtomR such that Before is the number of characters of the name of AtomL, Length is the number of characters of the name of Sub_atom and After is the number of characters of the name of AtomR
Usage:ISO
- Call and exit should be compatible with:
(basic_props:int/1)Before is an integer.
(basic_props:int/1)Length is an integer.
(basic_props:int/1)After is an integer.
(basic_props:atm/1)Sub_atom is an atom. - The following properties should hold at call time:
(basic_props:atm/1)Atom is an atom. - The following properties should hold upon exit:
(basic_props:int/1)Before is an integer.
(basic_props:int/1)Length is an integer.
(basic_props:int/1)After is an integer.
(basic_props:atm/1)Sub_atom is an atom.
PREDICATE
unify_with_occurs_check(X,Y)
Attempts to compute and apply a most general unifier of the two terms X and Y. Is true iff X and Y are unifiable.
Usage:ISO
- Call and exit should be compatible with:
(basic_props:term/1)X is any term.
(basic_props:term/1)Y is any term. - The following properties should hold upon exit:
(basic_props:term/1)X is any term.
(basic_props:term/1)Y is any term.
Known bugs and planned improvements
- There is a naive implementation of compound/1, perhaps is better to implement it as a builtin -- EMM.
