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Allow unknown described class members with a parse option #991
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So, you are suggesting a runtime option, not another type trait? |
I think this makes more sense as a runtime option, it's not that the type is special but rather that I don't care when parsing it. Like |
Do I understand it correctly, that you want to both allow missing fields, and allow extra fields? Or just the latter? |
To allow missing fields our standard solution is to use optional. Would this work for you? |
Allowing extra fields is more important to me, because its much more complicated to do beforehand and doesn't raise any questions on boost::json side. Allowing missing fields could be nice, but then you have to decide how to set them (letting them default-constructed seems an obvious solution). I already use optionals for null values, I didn't know it worked with missing values too! |
Hi, I'd like to make the parsing of my JSON config file more or less compatible across versions.
If a new field gets added I can easily add it if not present in the
json::value
before parsing it to make surevalue_to
has anything it needs. But a parse option to default construct in this case instead of erroring would not hurt.In a more complex case, if the config gets updated before the application parsing it
value_to
will complain because of size mismatch (see here). I'd like to disable this check with a parse option, because it's much harder to iterate all the described classes to make sure there are no extra properties in the JSON.The text was updated successfully, but these errors were encountered: