Polymorphic copy: Difference between revisions

=={{header|E}}==

In E, a generic copy for all objects can be built out of the serialization facility, by connecting an object recognizer to an object builder without even using any intermediate serialized form:

<lang e>def deSubgraphKit := <elib:serial.deSubgraphKit>

def copy(object) {

return deSubgraphKit.recognize(object, deSubgraphKit.makeBuilder())

}</lang>

Since E does not have any static dispatch, this cannot be non-polymorphic without also being non-generic. An example showing that it does indeed make copies.

<lang e>? def a := [1].diverge()

# value: [1].diverge()

? def b := copy(a)

# value: [1].diverge()

? b.push(2)

? a

# value: [1].diverge()

? b

# value: [1, 2].diverge()</lang>

(When I have time I will design a usage example which better conforms to the task description. --[[User:Kevin Reid|Kevin Reid]] 04:12, 1 March 2009 (UTC)) [[Category:E examples needing attention]]