This describes how bash users create, destroy, assign, and reference array
variables.  Array variables are variables whose values are arrays of strings,
and whose elements may be referenced individually.

CREATING
	- any variable may be declared as an array using `typeset -a'
	- an ordinary variable may be converted to an array using
	  `typeset -a'; the value becomes array[0]

	- there is a question of notation used to simultaneously declare
	  an array variable and populate it with values sequentially,
	  like ksh does with `set -A'.  `set -A' is a horrible choice;
	  it should be discarded immediately.

		- we can use `typeset -a array [values...]'

DESTROYING
	- `unset name' will destroy the array `name'
	- how to treat `typeset +a array'?
		- I think we should keep the variable, convert it from an
		  array to an `ordinary' variable, and make the value at
		  the smallest index of the array the value of the new
		  variable

ASSIGNING
	- array[index]=value will serve to assign values to individual
	  elements of the array
	- the subscript can be an arbitrary arithmetic expression; it
	  will be run through the expression evaluator
	- this can create arrays, too
		- this is analogous to defining a variable by simply
		  assigning to it

REFERENCING
	- $array will expand to all elements of the array, just like $*
	  expands to all the positional parameters
	- "$array" is like "$@"
	- ${array[index]} is used to reference array element `index', where
	  `index' can be an arbitrary arithmetic expression
		- two special values for `index': * and @ expand to all
		  elements of the array, just like $* and $@.  Quoting
		  behavior is the same, too
	- using a subscript is an error if a variable has not been declared
	  as an array (is this wise?)
	- ${#variable}, if `variable' is an array, expands to the number of
	  elements in the array
		- ${#variable[n]} expands to the length of variable[n].  n
		  may be an arbitrary arithmetic expression
		- ${#variable[*]} and ${#variable[@]} expand to the number of
		  elements in the array

OPEN QUESTIONS
	- should we allow them to be exported?  Ksh does not, but rc does