replace earlier binding infrastructure #408
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jonsequitur
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| return GetValues(context, ConstructorDescriptor.ParameterDescriptors); | ||
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| public object CreateInstance(BindingContext context) |
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Nit, consider GetInstance
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Can you explain how you think about the distinction here?
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On second look, Create is fine
| new SpecificSymbolValueSource(option)); | ||
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| public void BindMemberFromCommand<TValue>( |
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Does this mean BindMemberFromArgument? How will a tight coupling between commands and arguments here work with multiple arguments? I do not believe people think about commands having values as much as having arguments.
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Ignore the above because this isn't the place for it, but to clarify the confusion.
Our implementation is at odds with the ways I believe people think about the problem, and reflects an implementation detail. I do not believe people say "What's the value of that command?" Nor "What's the value of the argument on that option?" I think they would say "What's the value of the argument?" or "What's the value of the option?" and that is how Help seems laid out to me. I think this is going to be a rough cognitive load and reflects an implementation detail, and I know I will keep making this mistake whenever I am thinking about the real problem (the CLI).
But this has nothing to do with the problem we are trying to solve today.
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It does mean bind from the argument. The concern is a good one. I think conceptually "What is the value for this option" is more intuitive but less precise than "What is the value for this option's argument"? And yes, the value for a command will become more ambiguous with #310.
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| namespace System.CommandLine.Binding | ||
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| public class ModelDescriptor |
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AppModels will need to set just some properties. I think this will be a need for some other cases as well. How would you pass the list of PropertyDescriptors to this class?
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Do you mean set some properties that were not discovered via reflection?
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| public bool HasDefaultValue => false; | ||
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| public object GetDefaultValue() => null; |
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People may be confused by this - properties now appear to have default values. Not sure if we can work with them.
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This isn't intended to being limited the capabilities of reflection. The intention is to be able to annotate the model descriptor so that, for example, if you know that a given type behaviorally has a default, you can define that in the model.
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| public bool HasDefaultValue => false; | ||
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| public object GetDefaultValue() => null; |
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Consider returning the type default instead of null.
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@dotnet-bot test Ubuntu16.04 Release |
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…cts to DragonFruit
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jonsequitur
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@dotnet-bot test Ubuntu16.04 Release |
This is attempt #3 at a generalized model binding infrastructure with lessons learned from the previous two iterations. If we think this is a good approach, this is intended to replace the following types and their related code:
TypeBinderMethodBinderReflectionBinderThis is intended to address the following scenarios in a way that is flexible enough to be leveraged within app models, e.g. DragonFruit:
ParseResult, service provider, arbitrary inputs such as environment variables, etc.) to arbitrary types (including constructor parameters, property setters, and handler parameters)It also shifts the code for building options based on a method signature, which DragonFruit uses, into
System.CommandLine.DragonFruit. Some of this may later move under the app model work but as it's highly convention-based, we decided that it does not belong in the core library.