Data may be stored in variables. A variable can be of type string, real or logical, depending on the type of the expression in its definition. Any sequence of characters which is not recognized as expression or variable is treated as string. In this section, we will discuss only real and logical variables. String variables will be discussed in more detail in section 6.2.
Variables can occur anywhere in the input. For compatibility with MOLPRO92, variables can be defined using the SET command, but it is simpler and more flexible to use simply an equal sign as described below.