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tent_get(?X, -TV)

Get X's tentative value

X: Any term, typically a variable
TV: Will be bound to a (nonvar) term

Description

Get a variable's (or a whole term's) tentative value, i.e. create a term TV that represents the current tentative value of X.

If X is a tentative variable, TV is bound to the tentative value.
If X is a variable without tentative value, an error is raised.
If X is atomic, its tentative value is the same as X.
If X is a compound term, TV will be bound to a corresponding compound term with all variables replaced by their tentative values. The resulting term TV will be a proper instance of X.

Modes and Determinism

tent_get(?, -) is det

Exceptions

(tentative_value_not_set): X (or a subterm of X) has no tentative value

Examples

    ?- tent_set(X, 27), tent_get(X, TV).
    X = X{27 -> 0}
    TV = 27
    Yes (0.00s cpu)

    ?- tent_set(X, 27), tent_set(X, 99), tent_get(X, TV).
    X = X{99 -> 0}
    TV = 99
    Yes (0.00s cpu)

    ?- X = foo(Y), tent_set(X, foo(27)), X tent_get TV.
    X = foo(Y{27 -> 0})
    Y = Y{27 -> 0}
    TV = foo(27)
    Yes (0.00s cpu)

    ?- tent_get(27, TV).
    TV = 27
    Yes (0.00s cpu)

    ?- tent_get(X, TV).
    uncaught exception in throw(tentative_value_not_set)
    Abort

    ?- tent_get(foo(X), TV).
    uncaught exception in throw(tentative_value_not_set)
    Abort

tent_get(?X, -TV)

Description

Modes and Determinism

Exceptions

Examples

See Also