The command interpreter contains an expression evaluator, written by
Mark Morley. With it it is possible to make directly computations or to
parse arguments of commands (see 7 for more details). With this
expression evaluator it is possible to define *variables* and to
use *numerical functions*. If the command
interpreter receives a command that it not in its list of known commands,
this command is sent to the expression evaluator, evaluated as a numerical
expression, and the result is printed to screen. The evaluation gives 0 if
the expression is incorrect (it is an unknown variable for instance).

**Example : **

- interpcom -> a=1 1.000000 - interpcom -> b=-2 -2.000000 - interpcom -> newvar=a+b -1.000000

(here

- interpcom ->is the prompt of the interpreter). It is possible also to insert spaces :

- interpcom -> newvar = a + b

This will give the same result, except of course if you have a
command called `newvar`. So in general it is better to put no spaces
inside a numerical expression.

2009-11-12