Module KeyboardThread

Module intended to asynchronously capture user inputs without blocking the execution of other code. It was designed for the purpose of sending serial commands in real time to an Arduino.

Classes

class KeyboardThread (function: Callable = None, name: str = 'keyboard-input-thread')

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class KeyboardThread(threading.Thread):
        
        def __init__(self, function:Callable = None, name:str = 'keyboard-input-thread'):
                '''Initialize thread to receive keyboard inputs
                
                Parameters
                ----------
                function: func
                        Callback function that is execution whenever the user provides a keyboard input.
                        Must have the form `def function(string)` that takes a string 
                        (which is the user input) and performs some process. 
                
                name: str
                        label for the thread. If none is given it defaults to a generic name. 
                '''
                super(KeyboardThread, self).__init__(name=name, daemon=True)
                # variables
                self._function = function
                self._stop = threading.Event()
                self._input_data = ""                                   # initialize to empty string
                self._flag = False
                # initialize thread
                self.start()
        
        def run(self) -> None:
                '''Loop that is executed by the thread that listens to keyboard inputs.
                This loop will continue indefinately until `stop()` is called. 
                '''
                while self.is_active():
                        # get input
                        self._input_data = input()
                        if self._input_data != "":
                                self._flag = True       # data is unread
                        # callback
                        if self._function != None:
                                self._function( self._input_data ) #waits to get input + Return
        
        
        def setCallback(self, function:Callable) -> None:
                ''' Set the callback function that is called whenever the user submits an input
                
                Parameters
                ----------
                function: func
                        Callback function. See description of the class initializer. 
                '''
                self._function = function
        
        
        def input(self) -> str:
                '''Returns the keyboard input provided by the user. Updates whenever the user presses enter
                
                Returns
                -------
                input: str
                '''
                self._flag = False                      # data was read
                return self._input_data
        
        
        def flag(self) -> bool:
                '''Flag that indicates whether a new keyboard input has been provided and is unread.
                
                Returns
                -------
                flag: bool
                        `True` if a new input was provided and input() has been called. 
                        `False` if no new input is available and input() has beed called.
                '''
                return self._flag
        
        
        def stop(self) -> None:
                '''Kills the thread focus on receiving keyboard inputs. Must be called whenever the
                program has finished to prevent the thread from blocking the program from closing. 
                '''
                self._stop.set()
        
        
        def is_active(self) -> bool:
                '''Indicates whether the thread is active. 
                
                Returns
                -------
                flag: bool
                        True when the thread is active and listening to inputs
                        False when `stop()` is called and the thread is closed. 
                '''
                return not self._stop.isSet()
        
        
        #def start(self): # begin thread
                '''Function that starts the thread. 
                This function is called automatically when the class is initialized. It allows
                `input()` to update.
                '''

A class that represents a thread of control.

This class can be safely subclassed in a limited fashion. There are two ways to specify the activity: by passing a callable object to the constructor, or by overriding the run() method in a subclass.

Initialize thread to receive keyboard inputs

Parameters

function : func

Callback function that is execution whenever the user provides a keyboard input. Must have the form def function(string) that takes a string (which is the user input) and performs some process.

name : str

label for the thread. If none is given it defaults to a generic name.

Ancestors

• threading.Thread

Methods

def flag(self) ‑> bool

Expand source code

def flag(self) -> bool:
        '''Flag that indicates whether a new keyboard input has been provided and is unread.
        
        Returns
        -------
        flag: bool
                `True` if a new input was provided and input() has been called. 
                `False` if no new input is available and input() has beed called.
        '''
        return self._flag

Flag that indicates whether a new keyboard input has been provided and is unread.

Returns

flag : bool

True if a new input was provided and input() has been called. False if no new input is available and input() has beed called.

def input(self) ‑> str

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def input(self) -> str:
        '''Returns the keyboard input provided by the user. Updates whenever the user presses enter
        
        Returns
        -------
        input: str
        '''
        self._flag = False                      # data was read
        return self._input_data

Returns the keyboard input provided by the user. Updates whenever the user presses enter

Returns

input : str

 

def is_active(self) ‑> bool

Expand source code

def is_active(self) -> bool:
        '''Indicates whether the thread is active. 
        
        Returns
        -------
        flag: bool
                True when the thread is active and listening to inputs
                False when `stop()` is called and the thread is closed. 
        '''
        return not self._stop.isSet()


#def start(self): # begin thread
        '''Function that starts the thread. 
        This function is called automatically when the class is initialized. It allows
        `input()` to update.
        '''

Indicates whether the thread is active.

Returns

flag : bool

True when the thread is active and listening to inputs False when stop() is called and the thread is closed.

def run(self) ‑> None

Expand source code

def run(self) -> None:
        '''Loop that is executed by the thread that listens to keyboard inputs.
        This loop will continue indefinately until `stop()` is called. 
        '''
        while self.is_active():
                # get input
                self._input_data = input()
                if self._input_data != "":
                        self._flag = True       # data is unread
                # callback
                if self._function != None:
                        self._function( self._input_data ) #waits to get input + Return

Loop that is executed by the thread that listens to keyboard inputs. This loop will continue indefinately until stop() is called.

def setCallback(self, function: Callable) ‑> None

Expand source code

def setCallback(self, function:Callable) -> None:
        ''' Set the callback function that is called whenever the user submits an input
        
        Parameters
        ----------
        function: func
                Callback function. See description of the class initializer. 
        '''
        self._function = function

Set the callback function that is called whenever the user submits an input

Parameters

function : func

Callback function. See description of the class initializer.

def stop(self) ‑> None

Expand source code

def stop(self) -> None:
        '''Kills the thread focus on receiving keyboard inputs. Must be called whenever the
        program has finished to prevent the thread from blocking the program from closing. 
        '''
        self._stop.set()

Kills the thread focus on receiving keyboard inputs. Must be called whenever the program has finished to prevent the thread from blocking the program from closing.