Proposal: Support other assignment operators as part of the object initializer

[iam3yal]

Summary

Support other assignment operators as part of the object initializer.

Motivation

We can use object initializes to reduce some repetitions in the code when it comes to assignment of fields or properties but currently doing something like combining flags isn't supported.

Detailed design

Today if we want to combine flags we have to do that outside to the object initializer like so:

XmlReaderSettings settings = new XmlReaderSettings {
    ValidationType = ValidationType.Schema
};

settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessInlineSchema;
settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessSchemaLocation;
settings.ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings;

I'm proposing to support additional assignment operators so with this change we could do the following:

var settings = new XmlReaderSettings {
    ValidationType = ValidationType.Schema,
    ValidationFlags |= (XmlSchemaValidationFlags.ProcessInlineSchema 
                       | XmlSchemaValidationFlags.ProcessSchemaLocation 
                       | XmlSchemaValidationFlags.ReportValidationWarnings)
};

Drawbacks

Not aware of any.

Alternatives

Assign the property/field outside to the object initializer.

[vladd]

Does this proposal include relaxing the restriction on uniqueness? Which would allow something like

var settings = new XmlReaderSettings {
    ValidationType = ValidationType.Schema,
    ValidationFlags = XmlSchemaValidationFlags.ProcessInlineSchema,
    ValidationFlags |= XmlSchemaValidationFlags.ProcessSchemaLocation,
    ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings
};

Another question: is event subscription (which looks like assignment) included here too?

[iam3yal]

@vladd Nope, can you create a new issue about it? :)

[alrz]

Relates to #307

[Thaina]

@vladd I disagree on relaxing. Everything should only exist once

Your case is easier written as

var settings = new XmlReaderSettings {
    ValidationType = ValidationType.Schema,
    ValidationFlags = XmlSchemaValidationFlags.ProcessInlineSchema
                    | XmlSchemaValidationFlags.ProcessSchemaLocation
                    | XmlSchemaValidationFlags.ReportValidationWarnings,
};