# @ -- a binary operator

## Description

This operator is right associative.

## Ways to use symbol @ :

• "Expression @ Expression" -- see Expression -- the class of all expressions
• "Expression @ Holder" -- see Expression -- the class of all expressions
• "Expression @ Thing" -- see Expression -- the class of all expressions
• "Holder @ Expression" -- see Expression -- the class of all expressions
• "Holder @ Holder" -- see Expression -- the class of all expressions
• "Thing @ Expression" -- see Expression -- the class of all expressions

## For the programmer

The object @ is .

This operator may be used as a binary operator in an expression like x@y. The user may install binary methodsfor handling such expressions with code such as

         X @ Y := (x,y) -> ...

where X is the class of x and Y is the class of y.