metta.answer

Source: extensions/python/metta/answer.py.

The explicit answer a provider or operation may yield in place of a plain atom: bindings for the query's variables, an optional explicit value, a residue and an annotation. The wire form is ["a", theta, residue, k] with an optional trailing value, and it is transport-agnostic: the Python side sends it over janus, a remote backend sends the same shape over its own pipe, and a Prolog-side provider needs none of it because unification is already the binding step. .

• Construction validates shapes eagerly, so a malformed answer fails at the yield site it was written, not inside an engine callback .
• theta, value, residue, and k compose in one provider answer; residue closes in the engine and k becomes the selected carrier's annotation.

The entries below reproduce the source signatures and docstrings.

Answer

class Answer:

One explicit answer: theta binds the query's variables, and the atoms of the answer stay derivable as theta applied to the pattern.

A provider may yield one from match() in place of a plain atom, and a non-raw operation may return or yield one; the two forms mix freely in one stream. value is an explicit answer atom: a provider's value is unified with the query pattern under theta (the candidate-with- bindings form), and an operation's value is what the call reduces to, () when omitted, the relational reading. This is Hyperon's execute_bindings, an answer atom together with the bindings it is returned under.

residue and k complete the live wire form. A residue is an Atom evaluated by the engine under theta; a false closure drops that answer. k is admitted when the provider or operation context declares a non-Boolean annotation algebra: it orders under ranked, and a term-valued k is the source tag under prov. An undeclared k is refused rather than silently dropped.

Theta values are encoded with the standard value encoder: atoms pass through, scalars become their atoms, and a value needing a registered projection should be projected by the author. The resulting value's content type is its atom class, observable with get-metatype as Symbol, Variable, Grounded, or Expression; it is not the Python class name.

Answer.to_wire

def to_wire(self) -> list:

No docstring is defined.

Bindings

class Bindings(Answer):

The theta-only shorthand: Bindings({"x": 3}) answers by binding.