VARIABLES:

	Variable names must start with a letter, but can contain
	numbers, and underscores ( `_' ) after the 1st character. The
	binary and unary arithmetic operators are not allowed in
	variable names. RLaB is case sensitive. The variables `A' and
	`a' are different.  There is no restriction on the length of
	variables names.

	A variable can hold any kind of data. Variables hold scalar
	and matrix numerics as well as scalar and matrix strings,
	lists, built-in functions, and user-functions.

	A variable must be initialized, or used on the left-hand-side
	of an assignment before it can be otherwise used. Trying to
	use an uninitialized variable will result in an `UNDEFINED'
	message.

	Typing `who()' produces a list of the active variables in the
	workspace.  This list includes everything except builtin and
	user functions. Typing `what()' will produce a list of all the
	active builtin and user functions.

	Assignment to a variable destroys the current contents, and
	replaces them with the contents of the right hand side
	expression.  At present builtin functions cannot be
	re-assigned, but user-functions (and any other variable) can
	be re-assigned at any time.

	The storage space that a variable's data occupies can be
	freed for other usage with the clear command (see `help
	clear').
