Add custom docstring sections for hardware objects

docs/conf.py

@@ -88,6 +88,11 @@
 
 napoleon_numpy_docstring = False
 
+napoleon_custom_sections = (
+    ("Emits", "params_style"),  # For signals emitted by hardware objects
+    ("Hardware object properties", "params_style"),
+)
+
 
 # -- Options for sphinx.ext.viewcode
 # https://www.sphinx-doc.org/en/master/usage/extensions/viewcode.html

docs/source/dev/docs.md

@@ -79,3 +79,25 @@ The
 extension is enabled to handle docstrings within the Python code
 and it is configured for
 [Google-style docstrings](https://google.github.io/styleguide/pyguide.html#s3.8-comments-and-docstrings).
+
+Two custom docstring section titles are available to document *hardware objects*:
+
+* `Emits` for signals emitted by *hardware objects*;
+* and `Hardware object properties`
+  for the configuration settings of hardware object properties.
+
+They can be used like in this example:
+
+```python
+class Thing(HardwareObject):
+    """Some thing.
+
+    Hardware object properties:
+        colour (str):
+            The colour of the thing.
+
+    Emits:
+        isReady (bool):
+            Emitted when the readiness state changes.
+    """
+```

mxcubecore/HardwareObjects/abstract/AbstractActuator.py

@@ -18,32 +18,67 @@
 #  You should have received a copy of the GNU General Lesser Public License
 #  along with MXCuBE. If not, see <http://www.gnu.org/licenses/>.
 
-"""Abstract Actuator class.
-Defines the set/update value, get/set/update limits and validate_value
-methods and the get_value and _set_value abstract methods.
-Initialises the actuator_name, username, read_only and default_value properties.
-Emits signals valueChanged and limitsChanged.
-"""
+"""Abstract Actuator."""
 
 import abc
 import math
 from ast import literal_eval
 
 from mxcubecore.BaseHardwareObjects import HardwareObject
 
-
 __copyright__ = """ Copyright © 2010-2022 by the MXCuBE collaboration """
 __license__ = "LGPLv3+"
 
 
 class AbstractActuator(HardwareObject):
-    """Abstract actuator"""
+    """Abstract actuator defines methods common to all moving devices.
+
+    The `_set_value` method is the only abtract method that needs to be overloaded
+    in each implementation.
+
+    Attributes:
+        _nominal_value (float):
+            Current actuator value.
+        default_value (float | None):
+            Value specified by XML property, otherwise `None`.
+        _nominal_limits (tuple | None):
+            Values specified by XML property, otherwise `None`.
+        actuator_name (str):
+            Actuator name specified by XML property, otherwise `None`.
+        read_only (bool):
+            Read-only flag specified by XML property, otherwise `False`.
+
+    Hardware object properties:
+        actuator_name (str)
+        username (str)
+        read_only (bool)
+        default_value (bool | int)
+        default_limits (tuple[int, int])
+
+    Emits:
+        valueChanged (tuple[int]):
+            Tuple whose first and only item is the new value.
+
+            Emitted during initialization of the hardware object
+            and when setting a new value.
+
+        limitsChanged (tuple[tuple[int, int]]):
+            Tuple whose first and only item is a two-item tuple of the new limits
+            (low limit first and high limit second).
+
+            Emitted by `update_limits` if limit values are changed.
+
+        stateChanged (tuple):
+            Tuple whose first and only item is the new state.
+
+            Emitted by `force_emit_signals`
+    """
 
     __metaclass__ = abc.ABCMeta
 
     unit = None
 
-    def __init__(self, name):
+    def __init__(self, name: str):
         super().__init__(name)
         self._nominal_value = None
         self._nominal_limits = (None, None)
@@ -53,9 +88,7 @@ def __init__(self, name):
         self.username = None
 
     def init(self):
-        """Initialise actuator_name, username, read_only and default_value
-        properties.
-        """
+        """Init properties: actuator_name, username, read_only and default_value."""
         self.actuator_name = self.get_property("actuator_name")
         self.read_only = self.get_property("read_only") or False
         self.default_value = self.get_property("default_value")
@@ -72,37 +105,43 @@ def init(self):
     @abc.abstractmethod
     def get_value(self):
         """Read the actuator position.
+
         Returns:
-            value: Actuator position.
+            Actuator position.
         """
         return None
 
     def get_limits(self):
         """Return actuator low and high limits.
+
         Returns:
-            (tuple): two elements (low limit, high limit) tuple.
+            (tuple): Two-item tuple (low limit, high limit).
         """
         return self._nominal_limits
 
     def set_limits(self, limits):
-        """Set actuator low and high limits. Emits signal limitsChanged.
+        """Set actuator low and high limits and emit signal `limitsChanged`.
+
         Args:
-            limits (tuple): two elements (low limit, high limit) tuple.
+            limits (tuple): Two-item tuple (low limit, high limit).
+
         Raises:
-            ValueError: Attempt to set limits for read-only Actuator.
+            ValueError: Attempt to set limits for read-only actuator.
         """
         if self.read_only:
             raise ValueError("Attempt to set limits for read-only Actuator")
 
         self._nominal_limits = limits
         self.emit("limitsChanged", (self._nominal_limits,))
 
-    def validate_value(self, value):
+    def validate_value(self, value) -> bool:
         """Check if the value is within limits.
+
         Args:
-            value(numerical): value
+            value(numerical): Value.
+
         Returns:
-            (bool): True if within the limits
+            `True` if within the limits, `False` otherwise.
         """
         if value is None:
             return True
@@ -115,21 +154,25 @@ def validate_value(self, value):
     @abc.abstractmethod
     def _set_value(self, value):
         """Implementation of specific set actuator logic.
+
         Args:
-            value: target value
+            value: Target value.
         """
 
-    def set_value(self, value, timeout=0):
+    def set_value(self, value, timeout: float = 0) -> None:
         """Set actuator to value.
+
+        If `timeout == 0`: return at once and do not wait (default).
+
+        If `timeout is None`: wait forever.
+
         Args:
-            value: target value
-            timeout (float): optional - timeout [s],
-                             If timeout == 0: return at once and do not wait
-                                              (default);
-                             if timeout is None: wait forever.
+            value: Target value.
+            timeout (float): Optional timeout in seconds. Default is `0` (do not wait).
+
         Raises:
             ValueError: Invalid value or attemp to set read only actuator.
-            RuntimeError: Timeout waiting for status ready  # From wait_ready
+            RuntimeError: Timeout waiting for status ready (from wait_ready).
         """
         if self.read_only:
             raise ValueError("Attempt to set value for read-only Actuator")
@@ -142,10 +185,11 @@ def set_value(self, value, timeout=0):
         else:
             raise ValueError(f"Invalid value {value}")
 
-    def update_value(self, value=None):
-        """Check if the value has changed. Emits signal valueChanged.
+    def update_value(self, value=None) -> None:
+        """Check if the value has changed and emit signal `valueChanged`.
+
         Args:
-            value: value
+            value: Value.
         """
         if value is None:
             value = self.get_value()
@@ -154,10 +198,11 @@ def update_value(self, value=None):
             self._nominal_value = value
             self.emit("valueChanged", (value,))
 
-    def update_limits(self, limits=None):
-        """Check if the limits have changed. Emits signal limitsChanged.
+    def update_limits(self, limits=None) -> None:
+        """Check if the limits have changed and emit signal `limitsChanged`.
+
         Args:
-            limits (tuple): two elements tuple (low limit, high limit).
+            limits (tuple): Two-item tuple (low limit, high limit).
         """
         if not limits:
             limits = self.get_limits()
@@ -168,17 +213,17 @@ def update_limits(self, limits=None):
                 self._nominal_limits = limits
                 self.emit("limitsChanged", (limits,))
 
-    def re_emit_values(self):
-        """Update values for all internal attributes"""
+    def re_emit_values(self) -> None:
+        """Update values for all internal attributes."""
         self.update_value(self.get_value())
         self.update_limits(self.get_limits())
         super(AbstractActuator, self).re_emit_values()
 
-    def force_emit_signals(self):
-        """Forces to emit all signals.
+    def force_emit_signals(self) -> None:
+        """Force emission of all signals.
 
-        Method is called from gui
-        Do not call it within HWR
+        Method is called from GUI.
+        Do not call it within HWR.
         """
         self.emit("valueChanged", (self.get_value(),))
         self.emit("limitsChanged", (self.get_limits(),))