OntoDL Statement: set

Syntax

SetStatement	:=	set InternalReference SetOperator CopyMode? AssignedValue
AssignedValue	:=	InternalReference
	|	= QualifiedConcept
	|	= Text
SetOperator	:=	$= | -= | += | :=		controls the behavior of the set-statement, e. g. if a collection shall be extended by the AssignedValue or if the AssignedValue shall replace the existing contents of the collection (see section below for details)
CopyMode	:=	=		signals that a full copy of the Assigned Value shall be created before assigning it to an object (see section below for details)

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Semantics of the set-operator

Operator	Sematics	a=string b=string	a=object b=object	a=empty collection	a=collection b=string	a=collection b=object
$=	String Concatenation: If a and b are strings, the result is a concatenation of both string. If a is a collection of strings, b will be appended to each element of the collection. Collection elements may be filtered by qualifiers (e.g. set me.Designation[Language=de] $= ($ (German) append the text "(German)" to all German designations in the collection.	ab	error	{ b }	{a1b, .. , anb}	error
-=	No Replacement: the set operation is only performed if a is empty. If a already carries a value or is a non-empty collection, the value of a will not be altered.	a	a	{ b }	{ a }	{ a }
:=	Overwrite: The value of a is overwritten by b. In case a is a collection, b will be set as the only element of the collection. Collection elements may be filtered by qualifiers (e.g. set me.Designation[Language=de] := NULL removes all German language designation from the list).	b	b	{ b }	{ b }	{ b }
+=	Append to List: If a is a collection, b will be added to that collection. If a is a single object, a will be replaced by b.	b	b	{ b }	{ a1, .., an, b }	{ a1, .., an, b }
=	The default behavior is Append to List	b	b	{ b }	{ a1, .., an, b }	{ a1, .., an, b }