teletype

teletype is a high-level cross platform tty library compatible with Python 3.7+. It provides a consistent interface between the terminal and cmd.exe by building on top of terminfo and msvcrt and has no dependencies.

Installation

$ pip install teletype

I/O Utilities (teletype.io)

Reading Key Strokes

You can read keystrokes from stdin using get_key. Regular keys get returned as a string with a single character, e.g. "a", "1", "&", etc., while special keys and key combinations are returned as a string description, e.g. "space", "f12", "page-up", "ctrl-c", etc. A listing of the supported key combinations are listed in the codes module.

from teletype.io import get_key

print("Delete C:/ Drive? [y/n]")
selection = ""
while selection.lower() not in ("y", "n"):
    selection = get_key()
    if selection in ("ctrl-c", "ctrl-z", "escape"):
        selection = "n"
if selection == "y":
    print("Deleting C:/ drive...")
    delete_c_drive()
else:
    print("Leaving C:/ drive alone")

Styling Output

You can style strings with COLOURS and effects using style_format. Styles can be passed in either as a space delimited string or in a collection (e.g. a tuple, set, list, etc.). The passed text string is then wrapped in the appropriate ASCII escape sequences and returned. When printed the appropriate styles will be applied.

Alternatively you can you just pass these same parameters to style_print and accomplish this in one fell swoop. style_print takes the same parameters as the regular print function and can be used in place. In python3 you can even import style_print as print and use it in place. In order to pull this compatibility off for python2, the style argument must be specified explitly when calling, however, e.g. style_print("yolo", style="yellow").

Lastly, you can use strip_format to clear a string of any escape sequences that have been previously applied.

from teletype.io import style_format, style_print, strip_format


# All of these will do the same thing, that is print the message in red and bold
print(style_format("I want to stand out!", "bold red"))
print(style_format("I want to stand out!", ("red", "bold")))
style_print("I want to stand out!", style=["red", "bold"])


# Styles are cleared afterwards so everything else gets printed normally
print("I want to be boring")


# If for whatever reason you want to unstyle text, thats a thing too
text = style_format("I don't actually want too be styled", ("red", "bold"))
print(strip_format(text))

Cursor manipulation

The package includes quite a few helper functions to move the CURSOR around the screen. These include erase_lines, erase_screen, hide_cursor, show_cursor, and move_cursor; all of which are fairly self explanitory. The only word of caution is to remember to reset CURSOR visibility as its state will persist after the python interpreter has exited.

Components (teletype.components)

The package also includes components, higher level UI classes that are composed from the I/O functions and can be easily incorporated to any CLI application.

SelectOne

In [1]: from teletype.components import SelectOne
   ...:
   ...: picker = SelectOne(choices=["dog", "bird", "cat", "monkey", "gorilla"])
   ...: print("Your Favourite Animal?")
   ...: choice = picker.prompt()
   ...: print("Your choice: " + choice)

Your Favourite Animal?
 ❱ dog
   bird
   cat
   monkey
   gorilla
Your choice: dog

SelectMany

In [2]: from teletype.components import SelectMany
   ...:
   ...: picker = SelectMany(choices=["dog", "bird", "cat", "monkey", "gorilla"])
   ...: print("Your Favourite Animals?")
   ...: choices = picker.prompt()
   ...: print("Your choices: " + ", ".join(choices))

Your Favourite Animals?
❱● dog
 ○ bird
 ○ cat
 ○ monkey
 ○ gorilla
Your choices: dog

ProgressBar

In [3]: from time import sleep
   ...: from teletype.components import ProgressBar
   ...:
   ...: iterations = 15
   ...:
   ...: def iterable():
   ...:     for _ in range(iterations):
   ...:         sleep(0.2)
   ...:         yield
   ...:
   ...: ProgressBar("Progress Bar").process(iterable(), iterations)

Progress Bar: 15/15▐████████████████████████████████████████████████▌100%

ChoiceHelper

Although not a component in and of itself, ChoiceHelper can help you wrap your objects to make full use of components like SelectOne, SelectMany, or SelectApproval. This is completely optional-- normally these just use the string representations of objects for display, e.g. just printing options which are strings or calling their underlying __str__ methods.

Seperate Values from Labels

Sometimes this isn't an option or you might want to seperate the label of an object from its value. ChoiceHelper lets you specifiy these fields explicitly. You can apply styles, too.

In [4]: from teletype.components import SelectOne, ChoiceHelper
   ...:
   ...: choices = [
   ...:     ChoiceHelper(["corgi", "greyhound", "bulldog"], label="dog", style="blue"),
   ...:     ChoiceHelper(["siamese", "chartreux", "ragdoll"], label="cat", style="red"),
   ...:     ChoiceHelper(["zebra", "beta", "gold"], "fish", style="green")
   ...: ]
   ...:
   ...: print("favourite pet")
   ...: pet = SelectOne(choices).prompt()
   ...:
   ...: print("favourite breed")
   ...: breed = SelectOne(pet).prompt()

favourite pet
 ❱ dog
   cat
   fish

favourite breed
 ❱ corgi
   greyhound
   bulldog

Mnemonics

Another cool thing that ChoiceHelpers let you do is use mneumonics. These can be specified either using a single character, in which case they are underlined, or as a single character wrapped in square brackets, in which case they will be indicated using square brackets (e.g. for compatibility with dumb terminals).

This is used under the hood for SelectApproval to quickly select yes by pressing y and no by pressing n.

Styling Components (teletype.components.config)

You can set component styles using io.style_format.

from teletype.io import style_format, style_print
from teletype.components import ProgressBar, SelectMany

style = "red bold"
arrow = io.style_format(CHARS_DEFAULT["arrow"], style)
choices = ["dogs", "cats", "fish"]

io.style_print("\nSelect One", style=style)
SelectOne(choices, arrow=arrow).prompt()

You can also change character sets using set_char(key, value) where value is the unicode character you want to use and key is one of:

• arrow
• block
• left-edge
• right-edge
• selected
• unselected

License

MIT. See LICENSE.txt for details.