Enum BuiltinResult 

pub enum BuiltinResult {
    Success,
    Failure,
    Cut,
    NegationAsFailure(Term),
    Disjunction(Term, Term),
    IfThenElse(Term, Term, Term),
    IfThen(Term, Term),
    Conjunction(Term, Term),
    FindAll(Term, Term, Term),
    Once(Term),
    Call(Term),
    AtomLength(Term, Term),
    AtomConcat(Term, Term, Term),
    AtomChars(Term, Term),
    Write(Term),
    Writeln(Term),
    Nl,
    Compare(Term, Term, Term),
    Functor(Term, Term, Term),
    Arg(Term, Term, Term),
    Univ(Term, Term),
    Between(Term, Term, Term),
    CopyTerm(Term, Term),
    Succ(Term, Term),
    Plus(Term, Term, Term),
    MSort(Term, Term),
    Sort(Term, Term),
    NumberChars(Term, Term),
    NumberCodes(Term, Term),
}

Result of executing a builtin.

Variants

Success

The builtin succeeded (substitution may have been modified).

Failure

The builtin failed.

Cut

Cut: succeed and signal cut to the solver.

NegationAsFailure(Term)

Negation-as-failure: the solver needs to try the inner goal.

Disjunction(Term, Term)

Disjunction: try left, then right on backtracking.

IfThenElse(Term, Term, Term)

If-then-else: ;(->(Cond, Then), Else)

IfThen(Term, Term)

If-then (no else): ->(Cond, Then)

Conjunction(Term, Term)

Conjunction: ‘,’(A, B) — flatten into goal list.

FindAll(Term, Term, Term)

findall/3: Template, Goal, Result list.

Once(Term)

once/1: solve goal, take first solution only.

Call(Term)

call/1: execute a term as a goal.

AtomLength(Term, Term)

atom_length/2: atom, length

AtomConcat(Term, Term, Term)

atom_concat/3: atom1, atom2, result

AtomChars(Term, Term)

atom_chars/2: atom, char list

Write(Term)

write/1: write term to stdout (no newline).

Writeln(Term)

writeln/1: write term to stdout with newline.

Nl

nl/0: write newline to stdout.

Compare(Term, Term, Term)

compare/3: Order, Term1, Term2 — standard term ordering.

Functor(Term, Term, Term)

functor/3: Term, Name, Arity.

Arg(Term, Term, Term)

arg/3: N, Term, Arg.

Univ(Term, Term)

=../2: Term, List (univ).

Between(Term, Term, Term)

between/3: Low, High, X — integer enumeration.

CopyTerm(Term, Term)

copy_term/2: Original, Copy.

Succ(Term, Term)

succ/2: X, S — successor relation.

Plus(Term, Term, Term)

plus/3: X, Y, Z — addition relation.

MSort(Term, Term)

msort/2: List, Sorted.

Sort(Term, Term)

sort/2: List, Sorted.

NumberChars(Term, Term)

number_chars/2: Number, Chars.

NumberCodes(Term, Term)

number_codes/2: Number, Codes.

Trait Implementations

impl Debug for BuiltinResult

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.