# Using the Expression Editor
This guide explains what the Experience Editor is and how to use it.
# What is the Expression Editor?
The Expression Editor allows you to write a math or logic expression to alter the default behavior of the Module's prop.
# How to use Expressions
modV's Expression Editor is opened on most Module Controls by right-clicking a Control and selecting Edit Expression.
# Math Example
A Module with a prop spanning 0-1 may be too linear. You could adjust this by writing:
0.5 + sin((value * 360) * (PI / 180)) / 2
This expression creates a smooth sinusoidal curve between 0 and 1.
# Logic Example
You may need to constrain a value between a certain range based on a calculation. The Expression Editor supports logcal expressions also:
((0.5 - value) < 0) ? 0 : (0.5 - value)
This expression constrains the value between 0 and 0.5 by using a ternary operator (opens new window).
# Scope items
Scope items are presently broken. Documentation to follow when fixed.