docs/library/enum: Add Enum class.

Signed-off-by: Ihor Nehrutsa <[email protected]>

docs/library/enum.rst

@@ -0,0 +1,74 @@
+:mod:`enum` -- MicroPython Enum class like in Python.
+========================================================
+
+.. module:: enum
+   :synopsis: MicroPython Enum class like in Python.
+
+This module implements enumeration Enum class for MicroPython.
+Class Enum is based in dictonary `dict` class and provides a way to create enumeration
+objects with key-value pairs.
+
+Usage examples::
+
+    from enum import Enum
+
+    class State(Enum):
+        Stop = 10
+        Run = 20
+        Ready = 30
+
+
+    state = State()
+    print("state:", State())
+
+    current_state = state.Stop
+    print("current_state:", current_state, state.key_from_value(current_state))
+    if current_state == state.Stop:
+        print(" Stop state")
+    if current_state != state.Ready:
+        print(" Not a Ready state")
+        print(" Run!")
+        current_state = state.Run
+    print("current_state:", current_state, state.key_from_value(current_state))
+    # some process
+    i = -1
+    while current_state != state.Ready:
+        i += 1
+        if state.is_value(i):
+            if int(str(State(i))) == state.Ready:
+                current_state = state.Ready
+        print(".", end="")
+    print()
+    print("current_state:", current_state, state.key_from_value(current_state))
+    print("Done!")
+
+Output::
+
+    state: State({'Run':20, 'Stop':10, 'Ready':30})
+    current_state: 10 State.Stop
+     Stop state
+     Not a Ready state
+     Run!
+    current_state: 20 State.Run
+    ...............................
+    current_state: 30 State.Ready
+    Done!
+
+.. warning::
+
+    ``enum`` module allows XXX.
+
+    >>> isinstance(State.Run, State)
+    False
+    >>> State(state.Ready) == state.Ready
+    False
+    >>> int(str(State(state.Ready))) == state.Ready
+    True
+
+.. note::
+
+    ``enum`` module ZZZ.
+
+.. seealso::
+
+    YYY.

docs/library/index.rst

@@ -107,6 +107,7 @@ the following libraries.
    openamp.rst
    uctypes.rst
    vfs.rst
+   enum.rst
 
 The following libraries provide drivers for hardware components.