IDL_VALIDNAME - Determines whether a string may be used as a valid IDL variable name or structure tag name.
N_TAGS - Returns the number of tags in a structure.
REPLICATE - Creates an array of given dimensions, filled with specified value.
STRUCT_ASSIGN - Uses “Relaxed Structure Assignment” to copy structures.
STRUCT_HIDE - Prevents the IDL HELP procedure from displaying information about structures or objects.
TAG_NAMES - Returns the names of tags in a structure.