TuAssign, TuMerge, TuProject

Purpose: Copies an object to another object. Both parameters must denote objects.

The content of the fields in Source-object is copied into the Target-object. Each field from the Source-object is copied into the field of the Target-object bearing the same name.

The function TuAssign() copies all fields of the Source object. If a field is not already contained in the Target object, it is added.

The function TuMerge() copies all fields of the Source object that are not already contained in the Target object, which means that the Target object is redefined in such a manner that new fields are added, but no existing fields are overwritten.

The function TuProject() copies all fields of the Source object that are also contained in the Target object. No new data fields are appended to the Target object.

Return Values: All functions return the Target-object.

Example:

input:

<let s=emptytuple; t=emptytuple; t.x="A"; t.y="B"; s.y="C"; s.z="D"; ? t><br >< ? s><br ><let tass=copy(t); tmrg=copy(t); tprj=copy(t); TuAssign(tass,s); TuMerge(tmrg,s); TuProject(tprj,s); ? tass><br >< ? tmrg><br >< ? tprj >

resulting output:

(x="A", y="B") (y="C", z="D") (x="A", y="C", z="D") (x="A", y="B", z="D") (x="A", y="C")

See Also: TuAppField(), TuAssField(), TuDelField(), TuFieldSort(), TuInsField(), TuName(), TuSlice().