q

Quick and dirty debugging output for tired programmers.

Install q with pip install -U q.

All output goes to /tmp/q, which you can watch with this shell command:

tail -f /tmp/q

If TMPDIR is set, the output goes to $TMPDIR/q. On Windows, output goes to $HOME/tmp/q.

To print the value of foo, insert this into your program:

import q; q(foo)

To print the value of something in the middle of an expression, insert "q()", "q/", or "q|". For example, given this statement:

file.write(prefix + (sep or '').join(items))

... you can print out various values without using any temporary variables:

file.write(prefix + q(sep or '').join(items))  # prints (sep or '')
file.write(q/prefix + (sep or '').join(items))  # prints prefix
file.write(q|prefix + (sep or '').join(items))  # prints the arg to write

To trace a function's arguments and return value, insert this above the def:

import q
@q

To start an interactive console at any point in your code, call q.d():

import q; q.d()

The following Lightning Talk shows how powerful using q can be.

Other projects inspired by this one

• q for golang
• qq for elixir
• ic for Python - Similar library for Python, inspired by q.