.. meta::
    :description lang=en:
        xlSlim uses several magic global functions to allow access to the Excel internals, including access to the COM object model.


Magic Global Functions
======================

xlSlim has four magic global functions that are always available in Python code running within xlSlim: :func:`XLSLIM_UDFFUNC`, :func:`XLSLIM_INWINDOWFUNC`, :func:`XLSLIM_COMAPPFUNC` and :func:`XLSLIM_CALLERFUNC`.

.. py:function:: XLSLIM_UDFFUNC()

This global function can be used to access VBA functions as well as functions defined in other Excel add-ins. 

An example is this function that calls the `EUROCONVERT()` Excel add-in function. See :doc:`/user/udfs` for a detailed example.

.. code-block:: python

	def eur_conversion(amount: float, from_currency: str, to_currency: str) -> float:
		"""Convert to EUR using the Excel addin function EUROCONVERT."""
		return XLSLIM_UDFFUNC("EUROCONVERT", amount, from_currency, to_currency)

.. py:function:: XLSLIM_INWINDOWFUNC()

This global function can be used to check if the code is running while the user has the Excel Function Wizard open. In some cases, such as if the code is slow or has side effects, you may wish to not execute the function when the Function Wizard is open.

This Python code shows how it can be used to control which path a function executes:

.. code-block:: python

	XLSLIM_INWINDOWFUNC = None

	def slow_func():
		if XLSLIM_INWINDOWFUNC():
			return "Fast result"
		return "Slow result"
		
When in the Excel Function Wizard the Python code returns "Fast result".

.. image:: ../_static/global_function_in_func_wizard.png
  :width: 400
  :alt: Function in Excel Function Wizard

Else the Python code returns "Slow result".
  
.. image:: ../_static/global_function_not_in_func_wizard.png
  :width: 400
  :alt: Function not in Excel Function Wizard  
  
.. py:function:: XLSLIM_COMAPPFUNC()

This global function can be used to access the calling Excel application via COM. This is usually used when automating Excel or replacing VBA code. 

An example is this function that sets a cell value. See :doc:`/user/vba_replacement` and :doc:`/samples/pivot_table` for detailed examples.

.. code-block:: python

	XLSLIM_COMAPPFUNC = None

	def PythonRules():
		excel_obj = XLSLIM_COMAPPFUNC()
		app = excel_obj.Application
		app.ActiveWorkbook.ActiveSheet.Cells(2, 3).Value = "Python Rules!"
		
.. py:function:: XLSLIM_CALLERFUNC()

This global function can be used to find the address of the cell calling Python.

.. code-block:: python

	XLSLIM_CALLERFUNC = None

	def WhoCalledMe():
		caller = XLSLIM_CALLERFUNC()
		return f"I was called by ({caller.RowFirst},{caller.ColumnFirst}), ({caller.RowLast},{caller.ColumnLast})"