Using Caché Objects - InterSystems Documentation

Packages
Letting the compiler resolve names requires the #IMPORT directive in .MAC code or within
a class definition. If no import is specified, “short” class names are assumed to be in the
“User” or “%Library” packages:
// create an instance of Person
Set person = ##class(Person).%New()
// this is the same as:
Set person = ##class(User.Person).%New()
5.4.1 The IMPORT Directive
The #IMPORT directive lets you specify a package to search in for a particular class; for
example:
#import Lab
// Look for "Patient" within Lab package.
Set patient = ##class(Patient).%New()
You may have any number of #IMPORT statements within a MAC routine:
#import Lab
#import Accounting
// Look for "Patient" within Lab & Accounting packages.
Set pat = ##class(Patient).%New()
// Look for "Invoice" within Lab & Accounting packages.
Set inv = ##class(Invoice).%New()
The order of #IMPORT statements does not matter; It is an error to use a short class that is
ambiguous. That is, if you have the same class name in two or more packages and import all
of them, you will get an error when the compiler attempts to resolve the package name. To
avoid this error, use full names.
The class keyword, IMPORT, works in the same way: it specifies which packages to use for
resolving class references within the class definition and also that an #IMPORT statement
should be placed in the generated code. Note that if you do not have any #IMPORT statements,
it is as if you had specified:
#import User
Once you have any #IMPORT statement, User is NOT automatically imported. Therefore,
you may have to specify:
#import MyPackage
#import User
34 Using Caché Objects