union of all types
integer (on most systems a 32-bit signed value)
boolean (0 represents false; anything else represents true)
text string
arbitrary length list of any values
keyed look-up table
person; reference to a GEDCOM INDI record
family; reference to a GEDCOM FAM record
arbitrary length set of persons
GEDCOM node; reference to a line in a GEDCOM tree/record
event; reference to substructure of nodes in a GEDCOM record
type with no values
In the summaries of built-in functions below, each function is shown with its argument types and its return type. The types are from the preceding list. Sometimes an argument to a built-in function must be a variable; when this is so its type is given as XXX_V, where XXX is one of the types above. The built-ins do not check the types of their arguments. Variables can hold values of any type, though at any one time they will hold values of only one type. Note that EVENT is a subtype of NODE, and BOOL is a subtype of INT. Built-ins with type VOID actually return null (zero) values.