documentation.HELP! Python 2.5 Documentation

14.3.4 Option Callbacks

Python 2.5

previous page next page

Previous: 14.3.3.11 Other methods Up: 14.3 optparse Next: 14.3.4.1 Defining a callback

---

14.3.4 Option Callbacks

When optparse's built-in actions and types aren't quite enough for your needs, you have two choices: extend optparse or define a callback option. Extending optparse is more general, but overkill for a lot of simple cases. Quite often a simple callback is all you need.

There are two steps to defining a callback option:

• define the option itself using the callback action

• write the callback; this is a function (or method) that takes at least four arguments, as described below

---

Subsections

• 14.3.4.1 Defining a callback option
• 14.3.4.2 How callbacks are called
• 14.3.4.3 Raising errors in a callback
• 14.3.4.4 Callback example 1: trivial callback
• 14.3.4.5 Callback example 2: check option order
• 14.3.4.6 Callback example 3: check option order (generalized)
• 14.3.4.7 Callback example 4: check arbitrary condition
• 14.3.4.8 Callback example 5: fixed arguments
• 14.3.4.9 Callback example 6: variable arguments

---

Python Library Reference

Previous: 14.3.3.11 Other methods Up: 14.3 optparse Next: 14.3.4.1 Defining a callback

---

Release 2.5, documentation updated on 19th September, 2006.

See About this document... for information on suggesting changes.

previous page start next page

Get in touch

Submit feedback about this site to:

• [email protected]