75 lines
2.2 KiB
ReStructuredText
75 lines
2.2 KiB
ReStructuredText
Object conversion model
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=======================
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Base object types
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-----------------
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Pandemonium Variant
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- standalone: bool, int, real
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- pointer to builtin type (e.g. ``Matrix32``, ``AABB``, etc.)
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- pointer to generic ``Object``
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Python mp_obj_t
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- standalone: bool, small int, real (depend of implementation), qstr
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- pointer to generic struct (must have ``mp_obj_base_t base`` as first attribute)
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.. note:
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Variant and mp_obj_t instances are only used by copy, no memory management
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needed on themselves.
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Naming conventions:
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- GST: Pandemonium STandalone
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- GPB: Pandemonium Pointer Builtin
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- GPO: Pandemonium Pointer Object
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- PST: Python STandalone
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- PPB: Python Pointer Binding (proxy to Pandemonium data)
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- PPE: Python Pointer Exposed (defined with `@exposed` decorator)
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- PPI: Python Pointer Internal
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Variant memory management
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-------------------------
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For GPO, Variant contains a raw pointer on the Object and (not necessary) a
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reference on the Object.
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- If a reference is present, ref counting is at work.
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- If not, user need to do manual memory management by calling ``free`` method.
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For GPB, there is 3 possibilities:
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- No allocated memory for data (e.g. ``Rect2``), so nothing is done.
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- Data is stored in a memory pool (e.g. ``Dictionary``), so data's destructor
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is called which make use of ref counting to know what to do.
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- Classic C++ allocation for data (e.g. ``Matrix3``) so regular ``delete``
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is called on it.
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Conversions implicating a standalone
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------------------------------------
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Standalone doesn't need garbage collection and doesn't hold reference on
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other objects. Hence conversion is trivial.
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Conversion Pandemonium -> Python
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--------------------------
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Each GPB has a corresponding PPB, acting like a proxy from within the
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Python interpreter.
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GPO binding is done dynamically with the ``DynamicBinder`` using Pandemonium
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introspection (i.e. ``ObjectTypeDB``).
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It is possible in the future that to create static proxy for core GPO and rely
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on dynamic method as a fall-back for unknown classes (i.g. added by 3rd party).
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Conversion Python -> Pandemonium
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--------------------------
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PPB -> GPB described earlier.
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PPI objects cannot be converted back to Pandemonium.
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PPE instance are exposed as ``PyInstance`` (class exposed as ``PyScript``).
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