modelx.defmacro

defmacro(model=None, name=None, *funcs)

Decorator to create or update a macro from a Python function.

This convenience function serves as a decorator to create a new macro or update an existing macro directly from a Python function definition. Macros are Python functions that can be saved within a Model and executed to manipulate or query the model.

All macros in a model share the same dedicated global namespace. In the namespace, the model is defined as a global variable, mx_model as well as by its model name.

Examples

1. As a decorator without arguments

The code below creates a macro in the current model. If a macro with the same name already exists, updates its formula.

If the current model does not exist, a new model is created:

>>> import modelx as mx

>>> m = mx.new_model('MyModel')

>>> @mx.defmacro
... def get_model_name():
...     return mx_model._name

>>> get_model_name
<Macro MyModel.get_model_name>

>>> m.get_model_name()
'MyModel'

2. As a decorator with arguments

The code below creates a macro in a specified model with the specified name:

>>> m = mx.new_model('MyModel')

>>> @mx.defmacro(model=m, name='print_name')
... def print_model_name(message):
...     print(f"{message} {get_model_name()}")

>>> print_model_name
<Macro MyModel.print_name>

>>> m.print_name("This model is")
This model is MyModel

3. As a function

Creates multiple macros from multiple function definitions:

def foo():
    return mx_model._name

def bar():
    return foo()

foo, bar = defmacro(foo, bar)

Parameters:

• model (optional) – For usage 2, specifies the model to create the macro in. Defaults to the current model.

• name (optional) – For usage 2, specifies the name of the created macro. Defaults to the function name.

• *funcs – For usage 3, function objects. (model and name can also accept function objects for this usage.)

Returns:

For usage 1 and 2, the newly created single macro is returned. For usage 3, a list of newly created macros is returned.

Added in version 0.30.0.