Control constructs/predicates

Author(s): Daniel Cabeza, Manuel Hermenegildo.

Version: 1.11#222 (2004/5/24, 13:8:7 CEST)

Version of last change: 1.11#204 (2004/2/27, 19:38:32 CET)

This module contains the set of basic control predicates, except the predicates dealing with exceptions, which are in section Exception handling.

• Usage and interface (basiccontrol)
• Documentation on exports (basiccontrol)
• Documentation on internals (basiccontrol)

Usage and interface (basiccontrol)

Documentation on exports (basiccontrol)

PREDICATE: ,/2:

P , Q

Conjunction (P and Q).

Meta-predicate with arguments: goal,goal.

Usage: * ISO *

• The following properties should hold at call time: P is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1) Q is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1)

PREDICATE: ;/2:

P ; Q

Disjunction (P or Q).

Meta-predicate with arguments: goal;goal.

Usage: * ISO *

• The following properties should hold at call time: P is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1) Q is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1)

PREDICATE: ->/2:

P -> Q

If P then Q else fail, using first solution of P only. Also, (P -> Q ; R), if P then Q else R, using first solution of P only. No cuts are allowed in P.

Meta-predicate with arguments: goal->goal.

Usage: * ISO *

• The following properties should hold at call time: P is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1) Q is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1)

PREDICATE: !/0:

Usage: * ISO *

• Description: Commit to any choices taken in the current predicate.

PREDICATE: \+/1:

\+ P

Goal P is not provable (negation by failure). Fails if P has a solution, and succeeds otherwise. No cuts are allowed in P.

Meta-predicate with arguments: \+goal.

Usage: * ISO *

• The following properties should hold at call time: P is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1)
• The following properties hold globally: This predicate is understood natively by CiaoPP as not(X). (basic_props:native/2)

PREDICATE: if/3:

if(P, Q, R)

If P then Q else R, exploring all solutions of P. No cuts are allowed in P.

Meta-predicate with arguments: if(goal,goal,goal).

Usage:

• The following properties should hold at call time: P is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1) Q is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1) R is a term which represents a goal, i.e., an atom or a structure. (basic_props:callable/1)

PREDICATE: true/0:

Usage: * ISO *

• Description: Succeed (noop).
• The following properties hold globally: This predicate is understood natively by CiaoPP. (basic_props:native/1)

PREDICATE: fail/0:

Usage: * ISO *

• Description: Fail, backtrack immediately.
• The following properties hold globally: This predicate is understood natively by CiaoPP. (basic_props:native/1)

PREDICATE: repeat/0:

Usage: * ISO *

• Description: Generates an infinite sequence of backtracking choices.
• The following properties hold globally: This predicate is understood natively by CiaoPP. (basic_props:native/1)

PREDICATE: false/0:

No further documentation available for this predicate.

PREDICATE: otherwise/0:

No further documentation available for this predicate.

PREDICATE: $metachoice/1:

Usage:

• The following properties hold upon exit: Arg1 is an integer. (basic_props:int/1)
• The following properties hold globally: This predicate is understood natively by CiaoPP. (basic_props:native/1)

PREDICATE: $metacut/1:

Usage:

• The following properties should hold at call time: Arg1 is an integer. (basic_props:int/1)
• The following properties hold globally: This predicate is understood natively by CiaoPP. (basic_props:native/1)

PREDICATE: interpret_goal/2:

No further documentation available for this predicate.

PREDICATE: interpret_compiled_goal/2:

No further documentation available for this predicate.

PREDICATE: undefined_goal/1:

No further documentation available for this predicate.

PREDICATE: debug_goal/1:

No further documentation available for this predicate.

Documentation on internals (basiccontrol)

PREDICATE: |/2:

An alias for disjunction (when appearing outside a list). The alias is performed when terms are read in.

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