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The expression evaluator

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
- interpcom -> b=-2
- interpcom -> newvar=a+b


 - 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.