Import Expression Parser (for lack of a better name)

Import Expression Parser converts code like this:

x = collections.deque!(maxsize=2)

Into this equivalent code:

x = importlib.import_module('collections').deque(maxsize=2)

Usage

>>> import import_expression
>>> import_expression.eval('collections!.Counter("bccdddeeee")')
Counter({'e': 4, 'd': 3, 'c': 2, 'b': 1})

By default, the filename for SyntaxErrors is <string>. To change this, pass in a filename via the filename kwarg.

AST usage

Monkey Patching the REPL

>>> urllib.parse!.quote
  File "<stdin>", line 1
    urllib.parse!.quote
                ^
SyntaxError: invalid syntax
>>> import import_expression.patch
>>> import_expression.patch.patch(globals())
>>> urllib.parse!.quote
<function quote at 0xdeadbeef>

For convenience, you can also add the following two lines to your sitecustomize.py:

import import_expression.patch
import_expression.patch.patch()

And all REPL sessions will use the import expression syntax.

Limitations / Known Issues

• Some invalid syntax, such as urllib!.parse! is not yet detected, though that still works as though it was urllib.parse!.
• Due to the hell that is f-string parsing, and because ! is already an operator inside f-strings, import expressions inside f-strings will likely never be supported.
• Due to python limitations, results of import_expression.exec will have no effect on the caller's globals without an explicit globals argument.

FAQ

Actually asked questions for a new project! Golly gee!

• Why not just use __import__('x')?
  From the discord.py server:

  devon#4089: if i want to type _("thing")
  devon#4089: i have to move my fingers between three different locations
  devon#4089: both at the end and start of the string
  lambda#0987: yeah and [it's] also a pain to type on mobile so ok
  devon#4089: <<x>> is slightly less grating \

  For context, the originally proposed syntax was <<x>>.

License

Copyright © 2018 Benjamin Mintz <[email protected]>. All Rights Reserved.
Licensed under the MIT License. See the LICENSE.md file for details.