Hello World!

All the examples below, as well as a few other mentioned later, are based on an import hook which makes it possible to use the word function as being equivalent to the Python keyword lambda.

Think of this simple example as the "Hello World!" for this project.

Basic usage

Suppose that you want to use function as a keyword in Python, to mean the same thing as lambda, enabling you to write:


square = function x: x**2
print(f"{square(4)} is the square of 4.")

if __name__ == '__main__':
    print(f"And the square of 5 is {square(5)}")

You can run this program in a terminal as follows:

> python -m ideas my_program -a function_keyword
16 is the square of 4.
And the square of 5 is 25

The argument following -a is the name of a module that contains a function named add_hook. A search for such a module is first done in the current directory. If the module is not found in the current directory, it is assumed to exists in the ideas.examples directory included with ideas.

You may have noticed in the above that my_program does not include a .py extension. This is because my_program is imported: Python import hooks, by definition, only work on modules that are imported. Yet, you may have also noticed that it is imported with the name '__main__', so that it is run as though it is the main script.

Using the ideas-enabled interactive console

Ideas comes with its own interactive console. Here’s a sample session:

> python -m ideas -a function_keyword
Ideas Console version 0.0.31. [Python version: 3.10.2]

>>> cube = function x: x**3
>>> cube(3)

Just like with the normal CPython console, using the -i flag, you can run a main script and continue with the interactive console:

> python -im ideas -a function_keyword
16 is the square of 4.
And the square of 5 is 25
Ideas Console version 0.0.31. [Python version: 3.10.2]

>>> square(6)
>>> cube = function x: x**3
>>> cube(6)

Using with IPython or Jupyter notebook/lab

You can also use it with IPython, either in a terminal or in a Jupyter environment. Here is an example using IPython in a terminal.

In [1]: from ideas.examples import function_keyword

In [2]: function_keyword.add_hook()
Out[2]: <IdeasMetaFinder object for ideas.examples.function_keyword>

In [3]: cube = function x: x** 3

In [4]: cube(3)
Out[4]: 27

Starting from a standard CPython interpreter

Unlike the IPython interactive interpreter (aka ‘shell’), the CPython interpreter does not support directly transformations done by ideas. It is however possible to start the ideas console from the CPython interactive interpreter.

>>> from ideas.examples import function_keyword
>>> function_keyword.add_hook()
<IdeasMetaFinder object for ideas.examples.function_keyword>
>>> from ideas import console
>>> console.start()
Ideas Console version 0.0.34. [Python version: 3.10.2]

~>> sq = function x: x**2
~>> sq(3)

In this case, the ideas prompt ~>> is different from the CPython one.

Using with Pypy

According to a few quick tests we did, ideas works with Pypy just as well as it does with CPython.

Advanced usage

Information about more advanced usage can be found in this documentation. You can also do the following in a terminal:

python -m ideas -h