Variable Names

The n mark prints each argument next to its source expression. Neoprint reads the source line you called it from, so you never have to type 'name =' yourself.

import neoprint as np

name = 'Alice'
age = 30
city = 'New York'
np.show(name, age, city, ':n')

main.py:6   | name = "Alice"; age = 30; city = "New York"

Expressions work too

Plain names are only the beginning. Function calls and attribute accesses are also reconstructed:

names = ['Alice', 'Bob']
np.show(len(names), ':n')

class Box:
    def __init__(self):
        self.value = 42

box = Box()
np.show(box.value, ':n')

Enable it globally

If you want variable names on every call without repeating the mark, turn on the configuration switch:

import neoprint as np

np.config(show_varnames=True)

name = 'Alice'
np.show(name)       # name = "Alice"

Restore the default with np.config(show_varnames=False) or np.config.reset().

Limitations

• The function has to keep a recognizable name. Neoprint only inspects calls to print, show, debug, info, success, warning, error, format, and format_list. If you alias the import, for example from neoprint import show as s, the call no longer looks like one of those names and the mark cannot resolve the arguments. Use from neoprint import print (the name is print) instead of renaming.
• Literals have no name. np.show(42, ':n') prints 42, because there is nothing to reflect.
• Truthiness of the mark. :n0 hides names, :n1 (bare :n) shows them.

How it works, briefly

The source file of the calling frame is parsed with ast and cached per modification time. The analyzer finds the Call node on the reported line and reads the source segment of each argument. That is why the names are exactly what you wrote — including spacing inside longer expressions — and why the feature costs one file parse per source change, not per call.

See also Source Layers for how the head of a message is resolved.