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https://issues.apache.org/jira/browse/AVRO-18?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12702580#action_12702580
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Matt Massie commented on AVRO-18:
---------------------------------
I'd like to suggest that we use this enum with union in order support
discriminant unions much like xdr.
For example, in XDR, the syntax for a union is..
<code>
enum my_enum {
FOO,
BAR,
BAZ
};
union my_union switch (my_enum id){
case FOO:
string foo<>;
case BAR:
double bar;
case BAZ:
short baz;
default:
void
}
</code>
Those enums are important in order to know the type of object being
(de)serialized in the union.
Looking at the "interop.js" file in the current Avro distro, I see the union
field looks like
<code>
"unionField": ["boolean", "double", {"type":"array","items": "bytes"}],
</code>
which as far as I can tell, means that the union field can be a boolean, double
or array. How can you discriminate one from the other without a discriminant?
Maybe we need something like the following...
<code>
{"name": "Foo", "type": "enum", "values": ["a", "b", "c"]}
{"type": "union", "name": "my_union", "discriminant": "Foo",
"schemas": {
"a": "boolean",
"b": "double",
"c": {"type": "array", "items": "bytes"}
}.
"default": "void"
}
</code>
... or something similar?
> add enum type
> -------------
>
> Key: AVRO-18
> URL: https://issues.apache.org/jira/browse/AVRO-18
> Project: Avro
> Issue Type: New Feature
> Components: spec
> Reporter: Doug Cutting
>
> Avro schemas should support enum types.
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