Structures

Accessing members of structures

Indirect members of structures

dynamic lookup by name

dynamic lookup by position

Arrays of structures and structures as elements of arrays

Multiple references to the same structure

Assigning runtime space for structures (creating a structure)

Adding members to a structure

Adding a structure as a member

Adding an array as a member

Creating a copy of a structure

Accessing members of structures

	a.b
	a.b.c

indirect members of structures
(dynamic lookup by name)

	foo = "b"
	a[foo]

indirect members of structures
(dynamic lookup by position)

	foo = 5
	a[foo]

arrays of structures and structures as elements of arrays

Multiple references to the same structure

This is equivalent to a 'C' pointer to structure.

	t1 = ref(s)
	t2 = ref(t1)

There is no  '->'  operator in XPE. To access a member of a shared structure (structure with multiple references) use the  '.'   operator in exactly the same way as for a non-shared structure.

To obtain a uniqe copy of a shared structure use the 'value' function. However beware that a structure that has an embedded reference to itself cannot be completely copied as it will still have references to the original structure embedded in it.

e.g.

	t3 = value(t2)

Assigning runtime space for structures (creating a structure)

	s = struct()

adding members to a structure

	s.x = 0
	s.y = 0
	s.z = 0

adding a structure as a member

	s.x = struct()

adding an array as a member

	s.x = array(N)

creating a copy of a structure

	r = s

to use a member of this new structure simply use it as you would in 'C'. Beware however that you cannot read a value from a member if it has not first been initialised

see also

external interface to