unrepl 1.0.6

Translates REPL code fragments to proper Python code

The problem

Many blogs, courses, articles, (e)books present code fragments (and their output) from REPL output. But also doctests in programs are presented that way. Here's an example (from Fluent Python, 2nd edition):

>>> board = []
>>> for i in range(3):
...     row = ['_'] * 3
...     board.append(row)
... 
>>> board
[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]
>>> board[2][0] = 'X'  
>>> board
[['_', '_', '_'], ['_', '_', '_'], ['X', '_', '_']]

Or (from a RealPython course):

>>> prices = {
...    "banana": 1.20,
...    "pineapple": 0.89,
...    "apple": 1.57,
...    "grape": 2.45,
... }


>>> min(prices)
'apple'

>>> max(prices)
'pineapple'

That's all fine for reading (and doctests), but what if you want to run the code, or use it in another program, or just play with it?

In that case, you can copy/paste the code and manually remove the >>> and ... lines as well the generated output line(s).

Wait ... there must be a better way!

The solution

The small unrepl utility is designed to do just that.

You just copy the code to the clipboard, e.g.:

>>> for i in range(3):
...     row = ['_'] * 3
...     board.append(row)
... 
>>> board
[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]
>>> board[2][0] = 'X'  
>>> board
[['_', '_', '_'], ['_', '_', '_'], ['X', '_', '_']]"""))

and then run unrepl, which replaces the clipboard with:

board = []
for i in range(3):
    row = ['_'] * 3
    board.append(row)

board
#  [['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]
board[2][0] = 'X'
board
#  [['_', '_', '_'], ['_', '_', '_'], ['X', '_', '_']]

And for the second example:

prices = {
   "banana": 1.20,
   "pineapple": 0.89,
   "apple": 1.57,
   "grape": 2.45,
}
#  
#  
min(prices)
#  'apple'
#  
max(prices)
#  'pineapple'

You can also choose to use print statements for those lines that generate output, so you can actually run the code and get the proper output, like:

prices = {
   "banana": 1.20,
   "pineapple": 0.89,
   "apple": 1.57,
   "grape": 2.45,
}
#  
#  
_ = min(prices); print(repr(_)) # min(prices)
#  'apple'
#  
_ = max(prices); print(repr(_)) # max(prices)
#  'pineapple'

Note that the _ variable is set as it would be in the REPL.

Furthermore, unrepl can be used as a module (imported) in any Python program.

Installation

As unrepl.py is just a singe file program, you can just download unrepl.py from GitHub https://github.com/salabim/unrepl and put it in your working directory.

Alternatively, get it from PyPI with

pip install unrepl

Supported platforms

The utility should run on any Python implementation that has tkinter installed, thus Windows (tested), MacOS (not tested) and Linux (not tested). On top of that, the utility runs on iPadOS/iOS under Pythonista.

Command line: clipboard translation

When you run unrepl.py from the command line, the program grabs the contents of the clipboard and tries to remove the REPL overhead and handle prefixes a line that does not start with >>> or ... with a # to make it a comment. The line that generated the output is either

• untranslated or
• changed into a line with a proper print statement The program prompts whether to use print statements, if required.

Combination with AutoHotKey (Windows only)

Under Windows, unrepl can be called with a hotkey, that inserts the converted clipboard directly. So, for instance, if you want unrepl to be called with <Shift><Ctrl><Alt>v, add

^!+v::
    RunWait, X:\utilities\unrepl.py,,hide
    Send, ^v
    return

to your AutoHotKeyScript (assuming unrepl.py is in X:\utilities\)

If conversion is not possible, the clipboard will be pasted untranslated.

With the -u command line option, it possible to avoid the question whether or not to use print statements. Use unrepl -u y to use print statements. Use unrepl -u n to not use print statements (i.e. leave lines creating output untouched).

API

unrepl has just one public API function: unrepl:

def unrepl(code, use_print_statements=False):
    """
    Cleans up a code fragment from a REPL, with output lines

    Parameters
    ----------
    code : str
        code to clean up

    use_print_statements : bool
        if True (default) use print statements for lines that generate output
        if False, use lines untranslated for lines that generate output
        
    Returns
    -------
    Converted code, if proper REPL output
    
    Exceptions
    ----------
    Raises a ValueError if code is not proper REPL output, i.e.
    first line starts with `>>> `.
    """

Example usage

import unrepl

repl_output = """\
>>> import math
>>> angle = 90
>>> math.radians(angle)
1.5707963267948966
>>> math.pi / 2
1.5707963267948966
>>> _
1.5707963267948966
"""
unrepled = unrepl.unrepl(repl_output, use_print_statements=True)
print(unrepled)
print("execute ...")
exec(unrepled)

, with output

import math
angle = 90
_ = math.radians(angle); print(repr(_)) # math.radians(angle)
#  1.5707963267948966
_ = math.pi / 2; print(repr(_)) # math.pi / 2
#  1.5707963267948966
_ = _; print(repr(_)) # _
#  1.5707963267948966

execute ...
1.5707963267948966
1.5707963267948966
1.5707963267948966

Disclaimer

The unrepl utility does not provide a 100% reliable conversion. That's because the REPL output is not analyzed in depth and thus will only serve the most basic REPL outputs. Still, it does convert nearly all published REPL outputs in a proper way.