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The LifeLines programming language provides a long list of built-in functions. Most built-ins return values and require parameters. The values of the parameters and the values returned by built-ins belong to a variety of value types that are supported by the programming language. The table below describes the types of values that are used in LifeLines programs; these are the types of variables, parameters (to procedures, functions and built-ins) and return values (from functions and built-ins). In the remaining sections the built-in functions are separated into logical categories and described.
|Any||union of all types|
|Int||integer (on most systems a 32-bit signed value)|
|Bool||boolean (0 represents false; anything else represents true)|
|List||arbitrary length list of any values|
|Table||keyed look-up table|
|Indi||person; reference to a GEDCOM person record|
|Fam||family; reference to a GEDCOM family record|
|Set||arbitrary length set of persons|
|Node||GEDCOM node; reference to a line in a GEDCOM tree/record|
|Event||event; reference to substructure of nodes in a GEDCOM record|
|Void||type with no values|
In the summaries of built-in functions, 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) value.
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