users own dictionaries (if any)

userdict
	where user defines variables

systemdict
	operators defined (ie add)

	
ATTRIBUTES

	access attributes:
		unlimited, read-only, execute only, none
		fonts execute only?


	every obj is literal or executable

	/name =>  literal
	[ any1 ... anyn ] => literal array object
	{ any1 ... anyn } => executable array object

	
STACKS

	operand, dictionary, execution


EXECUTION

	Immediate:

		40 60 add 2 div

	Deferred:

		ie /foo {  any1 ... anyn } def
		...
		foo


	Execution of types:  (ie stuff with executable not literal attribute)

		int, real, bool, dict...   =>  still treated as data
		
		name => top down search of dicts then exec assoc val

		operator => built-in operator function called

		array => directly => operand stack
			indirectly => execution stack and exec elts until done


	EX:
			
		/inch {72 mul} def
		4 inch

		/inch =>  inch on operand stack
		{ 72 mul } => onto operand stack
		def => enter it to userdict (or other current dict)

		{ foo } directly => operand stack
			indirectly => execution stack