Usage¶

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:

# my_program.py

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)}")

Actually, with ideas, you can run this program in a terminal as follows:

> ideas -a function_keyword my_program
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.included directory included with ideas. Thus, for the example above, the name used by ideas is ideas.included.function_keyword.

In ideas -a function_keyword my_program, you may have noticed that my_program does not include a .py extension. This is a reminder that my_program is imported: Python import hooks, by definition, only work on modules that are imported. (However, you can include the .py extension and ideas will remove it before importing your program.) Yet, even though the program is imported, you may have also noticed from what is printed that it is imported with the name '__main__', so that it is nonetheless run as though it is the main script as one would expect. If you do not want the name to be __main__ but rather my_program, just add the flag --import_.

Using the ideas-enabled interactive console¶

Ideas comes with its own interactive console. Starting it on its own is as easy as this:

> ideas
Ideas Console version 0.2.1. [Python version: 3.11.9]
ideas>

You can also start it from within a standard Python interpreter:

>>> from ideas import console
>>> console.start()
Ideas Console version 0.2.1. [Python version: 3.11.9]
ideas>

Just like with the normal CPython console, using the -i flag when executing a module from the command line, you get to continue with the interactive console:

> ideas -a function_keyword my_program -i
16 is the square of 4.
And the square of 5 is 25
Ideas Console version 0.2.1. [Python version: 3.11.9]
ideas>

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.included.function_keyword import add_hook

In [2]: add_hook()
Out[2]: <Ideas import hook: ideas.included.function_keyword>

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

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

Using with Pypy¶

According to a few quick tests we did a while ago, ideas works with Pypy just as well as it does with CPython. If you dind that it doesn’t, please let us know by filing an issue.

Advanced usage¶

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

ideas -h

Multiple import hooks¶

You can have multiple import hooks added; for example:

(venv-ideas3.11) C:\Users\Andre\github\ideas
> ideas -a function_keyword -a nobreak
Ideas Console version 0.2.0. [Python version: 3.11.9]
ideas> import sys
ideas> for finder in sys.meta_path:
...    print(finder)
...
<IdeasMetaPathFinder for ideas.included.nobreak>
<IdeasMetaPathFinder for ideas.included.function_keyword>
<class '_frozen_importlib.BuiltinImporter'>
<class '_frozen_importlib.FrozenImporter'>
<class '_frozen_importlib_external.PathFinder'>

Note that once a meta_path finder finds the desired file to import, no other finder will be invoked. However, internally ideas will do its best to combine all the required transformations from all the IdeasHooks that will have been activated.

Always running by default¶

If you really like to have your custom hook or custom encoding enabled by default, it is possible to do so, provided you are not using a virtual environment. [2]

In what follows, I will use the decimal_math example which can be used either as an import hook or as a custom encoding. Source code

Import hook¶

To have decimal math working default, you can do the following.

1. Create a file named usercustomize.py containing the following:

from ideas.included import decimal_math
decimal_math.add_hook()

2. Assuming you are not in virtual environment, set the PYTHONPATH environment variable to the path where usercustomize.py is found. On Windows, this is most done by navigating where this file is found and typing: set PYTHONPATH=%cd%

You can now invoke your module doing the following:

python -c "import my_script"

I do not recommend that you do this.

Custom codec¶

# coding: decimal-math

# coding: decimal_math

To have it useable by default as a custom codec, you can do the following.

1. Create a file named usercustomize.py containing the following:

from ideas.included import decimal_math
decimal_math.register()

2. Assuming you are not in virtual environment, set the PYTHONPATH environment variable to the path where usercustomize.py is found. On Windows, this is most done by navigating where this file is found and typing: set PYTHONPATH=%cd%

3. At the top of the module you wish to be run with the special codec, add the following two lines:

   # coding: decimal_math
   from decimal import Decimal
   

You can now invoke your module doing the following:

python my_script.py

Again, I do not recommend that you do this.