IDL_VALIDNAME: Determine whether a string may be used as a valid variable name or structure tag name.

N_TAGS: Return the number of tags in a structure.

REPLICATE: Create an array of given dimensions, filled with specified value.

STRUCT_ASSIGN: Copy structures using relaxed structure assignment.

STRUCT_HIDE: Prevent HELP from displaying information about structures or objects.

TAG_NAMES: Return the names of tags in a structure.