[ruby.parslet] Give the arithmetic operators different precedences?

[Chris Corbyn]

Hi,

For expressions like:  2 * 2 + 1

How do I ensure 2 * 2 is reduced before the " + 1" part is reduced?

Maybe an infix calculator in the examples/ directory would be a nice example, 
as tends to be the "hello world" of parsers :)

Cheers,

Chris