Relationship to the Common Type System and the Common Language Specification
The Common Type System is the model that defines the rules the common language runtime follows when declaring, using, and managing types. The common type system establishes a framework that enables cross-language integration, type safety, and high-performance code execution. It is the raw material from which you can build class libraries.
The Common Language Specification (CLS) defines a set of programmatically verifiable rules that governs the interoperation of types authored in different programming languages. Targeting the CLS is an excellent way to ensure cross-language interoperation. Managed class library designers can use the CLS to guarantee that their APIs are callable from a wide range of programming languages. Note that although the CLS encourages good library design, it does not enforce it. For more information on this topic, see Writing CLS-Compliant Code.
You should follow two guiding principles with respect to the CLS when determining which features to include in your class library:
- Determine whether the feature facilitates the type of API development appropriate to the managed space.
The CLS should be rich enough to provide the ability to write any managed library. However, if you provide multiple ways to perform the same task, you can confuse users of your class library about correct design and usage. For example, providing both safe and unsafe constructs forces users to decide which to use. Therefore, the CLS encourages the correct usage by offering only type-safe constructs.
- Determine whether it is difficult for a compiler to expose the feature.
All programming languages will require some modification in order to target the runtime and the common type system. However, in order for developers to make a language CLS-compliant, they should not have to create a large amount of additional work. The goal of the CLS is to be as small as possible while offering a rich set of data types and features.