Demos

More demos, particularly related to building C++, will be added when possible.

custom_log_stage

Simple demo for how to modify the ci_exec defaults to suit user preferences. Go to demo ↱

Demos Program Execution

Wrapper module for executing each respective location from the repository root.

Each individual demo is executable on its own. However, users may also run a demo from repository root doing python demos/ <demo_name>.

By default the programs are not run in “animated” mode. The --animated flag is what is used to record the videos hosted on each individual demo page, which utilizes clear, PAUSE and a delay in calls to type_message(). See mock_shell() for more information.

clear()	Clear the console screen.
pause([amount])	Pause by amount using time.sleep().
type_message(message, *, delay)	Flush message to sys.stdout, sleep by delay after character.
mock_shell(program, *, cwd, delay, animated)	Run a “shell” program from the specified working directory.
run_demo(program, cwd, animated)	Run the specified demo program.

CI_EXEC_DEMOS_COVERAGE = False

Whether or not this is a coverage run of the demo files.

Warning

This should not be set unless invoking from tox. See notes in [testenv:docs] section of tox.ini at repository root.

windows_cmd_builtin(builtin)

Return a function that runs the specified builtin.

Note

There is a reason this is not in the main library. To deal with shell builtins requires a significant amount of extra work for little to no benefit. The demos just need "cls" to clear and "type" to cat.

The return is a function that can support:

*args

Any command line arguments to provide to the builtin.

**kwargs

Any keyword arguments to provide to subprocess.run(). This function will add check=True and shell=True unless these keys are already explicitly specified.

Parameters

builtin (str) – Any of the CMD builtins, such as "type" or "cls". No checking is performed!

clear()

Clear the console screen. Uses cls on Windows, and clear otherwise.

pause(amount=3.0)

Pause by amount using time.sleep().

This function exists so that it can be used for PAUSE statements in mock_shell().

Parameters

amount (float) – The amount of time to time.sleep() for. Default: 3.0 seconds.

type_message(message, *, delay)

Flush message to sys.stdout, sleep by delay after character.

Parameters

• message (str) – What to type. A trailing newline "\n" will be written at the end.

• delay (float) – The positive amount to time.sleep() after each character in message is written. Suggested value for simulating typing to the console: 0.05. Use 0.0 to avoid delays.

mock_shell(program, *, cwd, delay, animated)

Run a “shell” program from the specified working directory.

• Lines starting with # are “comment” lines, they will be printed to the screen using type_message().

• Lines starting with "$ " are a command to execute.

  • Commands executed will be printed to the screen using type_message().

There is also a notion of “animated” mode. When animated=True, the following special behavior is enabled:

• $ clear: calls clear(). In non-animated mode, clear is skipped.

• PAUSE or PAUSE=X.Y: call pause(), X.Y should be parseable as a float e.g., PAUSE=7.0 would pause for 7 seconds. In non-animated mode this is skipped.

• Calls to type_message() will have a delay=0.05. In non-animated mode the delay=0.0.

These scripts are not intended to be robust. Features are implemented as needed… this is not intended to be a real shell programming language! See demos/__main__.py for example program’s that can execute.

Parameters

• program (str) – The “shell” program to execute.

• cwd (str) – The directory to execute program from.

• delay (float) – Pass-through parameter for type_message().

• animated (bool) – Whether or not this is an “animated” shell, meaning commands such as clear or PAUSE should be executed.

run_demo(program, cwd, animated)

Run the specified demo program.

When animated=True, clear() the screen and sleep for 2 seconds to allow recording to begin. The delay parameter passed-through to type_message() will be set to 0.05. In non-animated mode the screen will not be cleared, and the delay will be 0.0.

Parameters

• program (str) – The “shell” program to execute with mock_shell().

• cwd (str) – Pass-through parameter to mock_shell().

• animated (bool) – Pass-through parameter to mock_shell().

main()

Create the argument parser and run the specified demo.