import
fitnesse.slim.test

You can store an object instance in a Slim symbol and then use the instance in parameters for methods or constructors.
Here createTestSlimWithString(string) is a factory method that creates a new TestSlim instance, sets the given string and returns the object.

The boolean isSame(Object other) method returns whether the other object is the same as the current TestSlim table actor.
The getStringFromOther(TestSlim other) method returns other.getStringArg().

script test slim
$TEST_SLIM_INSTANCE= create test slim with string Uncle
check get string arg null
reject is same $TEST_SLIM_INSTANCE
check get string from other $TEST_SLIM_INSTANCE Uncle
check return constructor arg 0

TestSlim has a constructor TestSlim(int, TestSlim)

script
start test slim 1 $TEST_SLIM_INSTANCE
check get string arg Uncle
check return constructor arg 1
reject is same $TEST_SLIM_INSTANCE

An instance stored in a Slim symbol can also be used for instance chaining (ChainWithInstanceTest).

script $TEST_SLIM_INSTANCE
ensure is same $TEST_SLIM_INSTANCE