EmbryoExt.py

"""Bridge between this COMP and the on-disk ``embryo`` package.

Lives in a Text DAT named ``EmbryoExt`` inside the Embryo COMP.  The COMP's
Component Editor points at it:

    Extension 1  ->  op('./EmbryoExt').module.EmbryoEngine(me)
    Name         ->  Embryo
    Promote      ->  on

WHERE THE PACKAGE COMES FROM
    The ``Embryopath`` parameter on the COMP names the folder that CONTAINS the
    ``embryo`` directory.  Leave it empty once the .toe sits beside the package
    and ``project.folder`` is used instead -- TouchDesigner already has that on
    ``sys.path``, so nothing needs configuring in the common case.

    It is a parameter rather than a constant in this file on purpose: a path is
    the one thing that differs per machine, and as a Folder-style par it gets a
    browse button and shows up in any audit that walks ``p.style == 'Folder'``.
"""

import sys
from pathlib import Path

_COMP = me.parent()


def _package_root() -> Path:
    """Folder containing the ``embryo`` package."""
    par = _COMP.par['Embryopath']
    folder = par.eval().strip() if par is not None else ''
    return Path(folder).expanduser() if folder else Path(project.folder)


def _ensure_importable() -> str:
    root = str(_package_root())
    if root not in sys.path:
        sys.path.insert(0, root)
    return root


_ensure_importable()

from embryo.engine import EmbryoEngine  # noqa: E402,F401
from embryo.dna import DNA              # noqa: E402,F401


def Reload():
    """Re-import the package after editing it on disk, then re-init the
    extension.  Pulse the COMP's ``Reloadcode`` parameter to run this.

    The ``global`` re-binding is the part that is easy to miss: this DAT's
    module holds its own reference to ``EmbryoEngine``, and that is what
    ``ext0object`` reads.  Reloading the package alone leaves that name bound
    to the previous class object, so re-initialising would hand you the old
    code back and the reload would look like it did nothing.
    """
    global EmbryoEngine, DNA

    import embryo
    _ensure_importable()
    embryo.reload_all()

    from embryo.engine import EmbryoEngine
    from embryo.dna import DNA

    _COMP.par.reinitextensions.pulse()
    print(f'Embryo: reloaded from {_package_root()} and re-initialised.')