MeTTa TS 1.2.0

MeTTa TS 1.2.0

MeTTa TS 1.2.0 adds eight importable standard libraries and makes the core list
operations run in linear time. Both changes keep the conformance oracle
byte-identical: the libraries stay off the prelude, and the faster list
operations return results equal to the prelude recursion up to variable renaming.

Standard libraries

Eight libraries from the PeTTa distribution are now importable modules. Load one
with (import! &self <name>). They are kept off the prelude, so a program that
imports none of them behaves exactly as before and the oracle is unchanged.

• vector, roman, combinatorics, patrick, datastructures, and spaces
  port the corresponding PeTTa utilities.
• nars is a Non-Axiomatic Reasoning System belief engine.
• pln is a Probabilistic Logic Networks reasoner with truth-value revision,
  negation, and deduction, reached through a PLN.Query entry point.

The ports follow Hyperon semantics rather than PeTTa's cons-cell representation:
list construction uses decons-atom/cons-atom, collapse yields a comma
tuple, and foldl/msort map to foldl-atom/sort.

Linear-time list operations

size-atom, map-atom, filter-atom, and foldl-atom over a literal list of
N elements now run in O(N) time on a constant native stack. The prelude
recursion was quadratic to cubic and overflowed the stack before reaching a
million elements.

size-atom gains a fast path that returns a ground tuple of inert data without
threading each element through the interpreter. map-atom, filter-atom, and
foldl-atom evaluate as grounded operations, and when the per-element function
is compiled they call it directly on the compiled path. Every result is equal to
the prelude recursion up to variable renaming, checked by an on/off differential.

A five-run minimum-time subprocess benchmark against PeTTa on SWI-Prolog, at
N=100000 and including process startup, with a one-clause user function per
element:

Operation	PeTTa	MeTTa TS	Speedup
size-atom	887 ms	170 ms	5.23x
map-atom	999 ms	348 ms	2.87x
filter-atom	966 ms	360 ms	2.68x
foldl-atom	999 ms	346 ms	2.89x

Trace bus and metta-debug

The core exposes an optional trace bus: pass a trace sink to a run and the
evaluator reports its reduce, rule-selection, grounded-dispatch, and
specialization decisions, with no cost when no sink is set. The @metta-ts/node
package adds a metta-debug command that runs a call under that sink and prints
those decisions, so a depth or dispatch question is a one-command diagnosis.

Fixes

A function that returns a control form such as let or if under
{tabling: true} now reduces it fully instead of leaving it partially reduced.

Verification

Checked on Linux with Node and pnpm.

• Build, type check, lint, and format checks pass across all ten packages.
• pnpm test passes: 1,208 tests across 123 files, with 38 optional live
  integration tests (7 files) skipped.
• The checked oracle passes all 23 corpus files. It is byte-identical to 1.1.7:
  the new libraries are opt-in and off the prelude, and the faster list
  operations equal the prelude recursion up to variable renaming.

Packages

All public packages use version 1.2.0:

npm install @metta-ts/core@1.2.0
npm install -g @metta-ts/node@1.2.0

Optional host packages use the same version:

npm install @metta-ts/py@1.2.0 pythonia
npm install @metta-ts/prolog@1.2.0