Fix up how enums work. Now they're always strings

examples/addressbook.capnp

@@ -0,0 +1,32 @@
+@0x934efea7f017fff0;
+
+struct Person {
+  id @0 :UInt32;
+  name @1 :Text;
+  email @2 :Text;
+  phones @3 :List(PhoneNumber);
+
+  struct PhoneNumber {
+    number @0 :Text;
+    type @1 :Type;
+
+    enum Type {
+      mobile @0;
+      home @1;
+      work @2;
+    }
+  }
+
+  employment @4 union {
+    unemployed @5 :Void;
+    employer @6 :Text;
+    school @7 :Text;
+    selfEmployed @8 :Void;
+    # We assume that a person is only one of these.
+  }
+}
+
+struct AddressBook {
+  people @0 :List(Person);
+}
+

examples/example.py

@@ -0,0 +1,57 @@
+import capnp
+addressbook = capnp.load('addressbook.capnp')
+
+def writeAddressBook(fd):
+    message = capnp.MallocMessageBuilder()
+    addressBook = message.initRoot(addressbook.AddressBook)
+    people = addressBook.initPeople(2)
+
+    alice = people[0]
+    alice.id = 123
+    alice.name = 'Alice'
+    alice.email = 'alice@example.com'
+    alicePhones = alice.initPhones(1)
+    alicePhones[0].number = "555-1212"
+    alicePhones[0].type = 'mobile'
+    alice.employment.school = "MIT"
+
+    bob = people[1]
+    bob.id = 456
+    bob.name = 'Bob'
+    bob.email = 'bob@example.com'
+    bobPhones = bob.initPhones(2)
+    bobPhones[0].number = "555-4567"
+    bobPhones[0].type = 'home'
+    bobPhones[1].number = "555-7654" 
+    bobPhones[1].type = addressbook.Person.PhoneNumber.Type.WORK
+    bob.employment.unemployed = None # This is definitely bad, syntax will change at some point
+
+    capnp.writePackedMessageToFd(fd, message)
+
+f = open('example', 'w')
+writeAddressBook(f.fileno())
+
+def printAddressBook(fd):
+    message = capnp.PackedFdMessageReader(f.fileno())
+    addressBook = message.getRoot(addressbook.AddressBook)
+
+    for person in addressBook.people:
+        print person.name, ':', person.email
+        for phone in person.phones:
+            print phone.type, ':', phone.number
+
+        which = person.employment.which()
+        print which
+
+        if which == addressbook.Person.Employment.Which.UNEMPLOYED:
+            print 'unemployed'
+        elif which == addressbook.Person.Employment.Which.EMPLOYER:
+            print 'employer:', person.employment.employer
+        elif which == addressbook.Person.Employment.Which.SCHOOL:
+            print 'student at:', person.employment.school
+        elif which == addressbook.Person.Employment.Which.SELF_EMPLOYED:
+            print 'unemployed'
+        print
+
+f = open('example', 'r')
+printAddressBook(f.fileno())