Dynamic Language Runtime Announced
Microsoft has announced that they are building an extension to the Common Language Runtime called the Dynamic Language Runtime (DLR). This extension is being designed to enable interoperability between dynamic languages in the same manner that the CLR enabled interoperability between statically typed languages.
Currently the biggest problem with dynamic language interoperability is the lack of a unified object model. Even when running on the same underlying platform like the CLR or JVM, each dynamic language had to independently extend the type system to support modifying classes at runtime. These implementations are inherently incompatible, making it difficult or impossible for languages like IronPython and RubyCLR to share objects.
The Dynamic Language Runtime offers a shared dynamic type system that should eliminate the barriers between Ruby and Python on the CLR platform. In theory, objects can be freely shared between programs written in each language.
In addition to the dynamic type system, the DLR project intends to offer other functionality for making it easier to develop new languages and port existing ones to the CLR. Jim Hugunin's write
The DLR is about giving you the best experience for your language - true to the language, excellent tools, performance and seamless integration with a wealth of libraries and platforms. The essential benefits of the DLR are about sharing. It lets language implementers share standard features rather than rebuilding them from scratch. This lets them focus on the features that make a given language unique rather than on reinventing yet another GC system.
Jim also lists the four dynamic languages that will initially be built on the DLR. Once these are complete and the platform stabilized, Microsoft intends to work with other language developers that wish to target the DLR.
Microsoft has mentioned that VB was going to adopt more dynamic features, but it never before hinted that it would approach the level of Python or Ruby. What this means for the language is still unknown.
It is important to note that the DLR is being released as open source. This is very good news for the Mono team, as Miguel de Icaza explains.
The release for the DLR is done under the terms of the Microsoft Permissive License (MsPL) which is by all means an open source license. This means that we can use and distribute the DLR as part of Mono without having to build it from scratch. A brilliant move by Microsoft.
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