JSON doesn't support lazy deserialization about bond HOT 8 OPEN

Text protocols like JSON and Xml don't support bonded<T>. This is because the implementation uses streaming parsers (for better performance) which can't be cloned. bonded<T> has lazy deserialization semantics which means that during deserialization of the containing structure it needs to make a clone of the protocol in order to deserialize from it later. It will work if you change your schema to:

struct Record
{
    0: string Name;
    1: vector<double> Constants;
    2: InnerStruct data;
}

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What I want to achieve is to parse InnerStruct's baseType field and than apply proper deserializer to it. Is it possible with Json parser?

Schema like this:

namespace Examples
struct InnerStruct
{
    10: optional string baseType;
};
struct InnerStruct1: InnerStruct
{
    10: optional string baseType;
    20: string newField1;
};
struct InnerStruct2 : InnerStruct
{
    10: optional string baseType;
    20: string newField2;
};
struct Record
{
    0: string Name;
    1: vector<double> Constants;
    2: optional InnerStruct data;
};

from bond.

No, today polymorphism is not supported with JSON or Xml.

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Do you have it in plans? Is there a way to implement it using any sort of extensibility bond provides?

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We intend to support it but we are still investigating what the best approach is.

One option, which could be implemented using Bond extensibility mechanisms, is to implement JSON protocol using a DOM parser. This would require a new parser functionally equivalent to SimpleJsonParser (although probably simpler because stream parsing it more difficult). This is how polymorphism works with JSON in the C++ implementation.

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@abaranch for information.

@sapek we need a tool to parse Application Insights events which are bond-schema JSON in our tests. We are using custom tool to generate those parsers, but would really like to use something official, at least for functional tests. Can you please keep us posted on this work

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That be very nice to have this addressed.

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👍 Agreed. It would be nice to see this implemented.

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