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85 lines
2.8 KiB
ReStructuredText
85 lines
2.8 KiB
ReStructuredText
Global Variables
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----------------
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In some cases you might need to share a global variable across multiple lambdas. For example, global variables can be
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used to store the state of a garage door.
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.. code-block:: yaml
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# Example configuration entry
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globals:
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- id: my_global_int
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type: int
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restore_value: no
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initial_value: '0'
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# Example for global string variable
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- id: my_global_string
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type: std::string
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restore_value: yes
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max_restore_data_length: 24
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initial_value: '"Global value is"'
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# In an automation
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on_...:
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then:
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- lambda: |-
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if (id(my_global_int) > 5) {
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// global value is greater than 5
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id(my_global_int) += 1;
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} else {
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id(my_global_int) += 10;
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}
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ESP_LOGD(TAG, "%s: %d", id(my_global_string).c_str(), id(my_global_int));
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Configuration variables:
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- **id** (**Required**, :ref:`config-id`): Give the global variable an ID so that you can refer
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to it later in :ref:`lambdas <config-lambda>`.
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- **type** (**Required**, string): The C++ type of the global variable, for example ``bool`` (for ``true``/``false``),
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``int`` (for integers), ``float`` (for decimal numbers), ``int[50]`` for an array of 50 integers, etc.
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- **restore_value** (*Optional*, boolean): Whether to try to restore the state on boot up.
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Be careful: on the ESP8266, you only have a total of 96 bytes available for this! Defaults to ``no``.
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- **max_restore_data_length** (*Optional*, integer): Only applies to variables of type ``std::string``. ESPHome will allocate enough space for this many characters,
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plus single character of overhead. Strings longer than this will not be saved. The max value of this variable is 254 characters, and the default is 63 characters.
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- **initial_value** (*Optional*, string): The value with which to initialize this variable if the state
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can not be restored or if state restoration is not enabled. This needs to be wrapped in quotes! Defaults to
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the C++ default value for this type (for example ``0`` for integers).
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.. _globals-set_action:
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``globals.set`` Action
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----------------------
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This :ref:`Action <config-action>` allows you to change the value of a ``global``
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variable without having to use the lambda syntax.
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.. code-block:: yaml
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on_...:
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- globals.set:
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id: my_global_var
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value: '10'
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Configuration variables:
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- **id** (**Required**, :ref:`config-id`): The :ref:`config-id` of the global variable to set.
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- **value** (**Required**, :ref:`templatable <config-templatable>`): The value to set the global
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variable to.
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.. note::
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This action can also be written in lambdas:
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.. code-block:: cpp
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id(my_global_var) = 10;
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See Also
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--------
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- :doc:`index`
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- :doc:`/automations/actions`
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- :doc:`/automations/templates`
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- :ghedit:`Edit`
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