PPL allows the following operators to be used in expressions (lvalue and rvalue are simply the values to the left and right, respectively, of binary operators):

    (  - Start sub-expression (also allows [ to be used)
    )  - End sub-expression (also allows ] to be used)
    ^  - Raise lvalue to the power of rvalue (also allows ** to be used)
    *  - Multiply lvalue by rvalue
    /  - Divide lvalue by rvalue
    %  - Remainder of lvalue divided by rvalue
    +  - Add rvalue to lvalue
    -  - Subtract rvalue from lvalue
    =  - Is lvalue equal to rvalue (also allows ==)
    <> - Is lvalue not equal to rvalue (also allows != and ><)
    <  - Is lvalue less than rvalue
    <= - Is lvalue less than or equal to rvalue (also allows =<)
    >  - Is lvalue greater than rvalue
    >= - Is lvalue greater than or equal to rvalue (also allows =>)
    !  - Logical not of rvalue
    &  - Logical and of lvalue with rvalue (also allows &&)
    |  - Logical or of lvalue with rvalue (also allows ||)