1.3.1 Qwt5.iqt

The programming style imposed by PyQt (and other GUI toolkit wrappers) is to create an application instance with some widgets and to enter into an event loop that locks you from the Python command line interpreter.

Module iqt works by hooking qApp->processEvents() on the event hook of the readline module. The GNU readline library closes the event loop by calling qApp->processEvent() at a maximum rate of 10 times per second while reading your keyboard input.

python -i ICompass.py

My .pythonrc.py file loads the modules readline, rlcompleter and iqt. Then, it configures readline for tab-completion and history saving and cleans up the global namespace. Finally, it loads the modules scipy, qwt, and qt, while setting up the help system for scipy:

# Set your PYTHONSTARTUP environment variable to $HOME/.pythonrc.py
#
# inspired by:
# http://opag.ca/wiki/OpagCode/OpagSnippets

from atexit import register
from os import path
import readline
import rlcompleter

# Sets up a tab for completion (use a single space to indent Python code).
readline.parse_and_bind('tab: complete')

historyPath = path.expanduser(' /.python_history')
readline.set_history_length(1000)

# Reads the history of the previous session, if it exists.
if path.exists(historyPath):
    readline.read_history_file(historyPath)

# Sets up history saving on exit.
def save_history(historyPath=historyPath, readline=readline):
    readline.write_history_file(historyPath)

register(save_history)

# Cleans up the global name space.
del register, path, readline, rlcompleter, historyPath, save_history

# Tries to make the PyQt and PyQwt widgets usable from the command line.
try:
    import PyQt4.Qwt5.iqt
    del PyQt4.Qwt5.iqt
except ImportError:
    pass

# Tries to import PyQt and Qwt.
try:
    import PyQt4.Qwt5 as Qwt
    import PyQt4.Qt as Qt
except ImportError:
    pass

# Sets up the SciPy help for tab completion: help(sp.optimize.leastsq).
try:
    import numpy as np
    import scipy as sp
    sp.pkgload()
except ImportError:
    pass

# Local Variables: ***
# mode: python ***
# End: ***