zoomy_core.symbolic.auto_eval_guard module

Context manager that bans sympy auto-evaluation inside its block.

Used in tests + the slim walkthrough to verify the primitive layer never silently fires a math rule. When the guard is active, calling .doit() on any sympy Basic object raises AutoEvalForbidden with a stack trace pointing at the offender.

Usage:

from zoomy_core.symbolic.auto_eval_guard import AutoEvalGuard

with AutoEvalGuard():
    # Any .doit() call here will raise.
    ...

The guard also bans sp.simplify, sp.cancel, sp.together, sp.factor, sp.collect, sp.diff, sp.integrate — the non-structural calls the redesign forbids inside the symbolic package. sp.expand is permitted (Canonicalise uses it) — restrict its kwargs at call sites instead.

exception zoomy_core.symbolic.auto_eval_guard.AutoEvalForbidden

Bases: RuntimeError

Raised when a forbidden sympy auto-evaluation call fires.

The redesign’s invariant is: every math rule is invoked by an explicit primitive. Sympy’s auto-evaluation calls (.doit(), sp.simplify, etc.) bypass that surface and cause subtle order-of-operations bugs. The guard makes any such call a hard failure.

class zoomy_core.symbolic.auto_eval_guard.AutoEvalGuard

Bases: object

Monkeypatch sympy.Basic.doit and the eval-style sympy helpers to raise. Restored on exit.