Dynamic Language Runtime
Encyclopedia
The Dynamic Language Runtime (DLR) from Microsoft
is an ongoing effort to bring a set of services that run on top of the Common Language Runtime
(CLR) and provides language services for several different dynamic languages. These services include:
The DLR is used to implement dynamic languages like Python
and Ruby
on the .NET Framework
.
By having several dynamic language implementations share a common underlying system, it should be easier to let these implementations interact with one another. For example, it should be possible to use libraries from any dynamic language in any other dynamic language. In addition, the hosting API allows interoperability with statically typed CLI languages like C#.
2007. Microsoft planned to ship a first usable 1.0 version of the DLR at the same time as IronPython 2.0, by the end of 2008.
Microsoft shipped .NET DLR 0.9 beta on the 26 November 2008, and final 0.9 on 10 December 2008. Version 1.0 shipped on April 16, 2010. On 16 July 2010, Microsoft changed the license of the DLR from the Microsoft Public License to the Apache License, v2.0.
, a .NET implementation of the Ruby language, and for IronPython
.
In 2007, Microsoft planned to use the DLR for the upcoming Visual Basic 2010 (VB 10.0) and Managed JScript
(ECMAScript
3.0). However, as of August 2009, Microsoft has no more plans to implement Managed JScript
(ECMAScript
3.0) on the DLR, and no further mention of Visual Basic .NET
working on the DLR has been made by Microsoft on Visual Basic development updates. Similar to C#, Visual Basic would have been able to access objects from dynamic languages built on the DLR such as IronPython
and IronRuby
.
IronScheme
, an upcoming Scheme implementation, was planning to build upon the DLR. This idea was abandoned because the DLR branch
the project used became out of sync with the trunk
, and also because (according to the project coordinator) the current version of the DLR at that time could not support the majority of Scheme's requirements.
, whose nodes correspond to a specific functionality that is common to many dynamic languages. This architecture is backed by the idea that the number of elementary language constructs that would have to be implemented on the generic stack should be inherently limited. The DLR dynamically generates code corresponding to the functionality expressed by these nodes. The compiler for any dynamic language implemented on top of the DLR has to generate DLR abstract trees, and hand it over to the DLR libraries.
The DLR provides dynamically-updated
of the method with the actual implementation.
In contrast to other efforts like the Parrot virtual machine
(with no dependencies) or Da Vinci Machine
(built on Java's JVM by adding new bytecodes in the JVM instruction set
), the DLR is built on top of the existing Common Language Runtime
, the .NET Framework
virtual machine.
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
is an ongoing effort to bring a set of services that run on top of the Common Language Runtime
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
(CLR) and provides language services for several different dynamic languages. These services include:
- A dynamic type systemType systemA type system associates a type with each computed value. By examining the flow of these values, a type system attempts to ensure or prove that no type errors can occur...
, to be shared by all languages utilizing the DLR services - Dynamic method dispatchDynamic dispatchIn computer science, dynamic dispatch is the process of mapping a message to a specific sequence of code at runtime. This is done to support the cases where the appropriate method can't be determined at compile-time...
- Dynamic code generation
- Hosting API
The DLR is used to implement dynamic languages like Python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
and Ruby
Ruby (programming language)
Ruby is a dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was first developed and designed by Yukihiro "Matz" Matsumoto...
on the .NET Framework
.NET Framework
The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...
.
By having several dynamic language implementations share a common underlying system, it should be easier to let these implementations interact with one another. For example, it should be possible to use libraries from any dynamic language in any other dynamic language. In addition, the hosting API allows interoperability with statically typed CLI languages like C#.
History
Microsoft's Dynamic Language Runtime project was announced by Microsoft at MIXMIX (Microsoft)
MIX is a Microsoft conference held annually for web developers and designers at which Microsoft showcases upcoming web technologies. The conference is held each spring at the Venetian Hotel in Las Vegas...
2007. Microsoft planned to ship a first usable 1.0 version of the DLR at the same time as IronPython 2.0, by the end of 2008.
Microsoft shipped .NET DLR 0.9 beta on the 26 November 2008, and final 0.9 on 10 December 2008. Version 1.0 shipped on April 16, 2010. On 16 July 2010, Microsoft changed the license of the DLR from the Microsoft Public License to the Apache License, v2.0.
Supported languages
The DLR services are currently used in the development version of IronRubyIronRuby
IronRuby is an implementation of the Ruby programming language targeting Microsoft .NET framework. It is implemented on top of the Dynamic Language Runtime , a library running on top of the Common Language Infrastructure that provides dynamic typing and dynamic method dispatch, among other things,...
, a .NET implementation of the Ruby language, and for IronPython
IronPython
IronPython is an implementation of the Python programming language targeting the .NET Framework and Mono. Jim Hugunin created the project and actively contributed to it up until Version 1.0 which was released on September 5, 2006. Thereafter, it was maintained by a small team at Microsoft until...
.
In 2007, Microsoft planned to use the DLR for the upcoming Visual Basic 2010 (VB 10.0) and Managed JScript
JScript
JScript is a scripting language based on the ECMAScript standard that is used in Microsoft's Internet Explorer.JScript is implemented as a Windows Script engine. This means that it can be "plugged in" to any application that supports Windows Script, such as Internet Explorer, Active Server Pages,...
(ECMAScript
ECMAScript
ECMAScript is the scripting language standardized by Ecma International in the ECMA-262 specification and ISO/IEC 16262. The language is widely used for client-side scripting on the web, in the form of several well-known dialects such as JavaScript, JScript, and ActionScript.- History :JavaScript...
3.0). However, as of August 2009, Microsoft has no more plans to implement Managed JScript
JScript
JScript is a scripting language based on the ECMAScript standard that is used in Microsoft's Internet Explorer.JScript is implemented as a Windows Script engine. This means that it can be "plugged in" to any application that supports Windows Script, such as Internet Explorer, Active Server Pages,...
(ECMAScript
ECMAScript
ECMAScript is the scripting language standardized by Ecma International in the ECMA-262 specification and ISO/IEC 16262. The language is widely used for client-side scripting on the web, in the form of several well-known dialects such as JavaScript, JScript, and ActionScript.- History :JavaScript...
3.0) on the DLR, and no further mention of Visual Basic .NET
Visual Basic .NET
Visual Basic .NET , is an object-oriented computer programming language that can be viewed as an evolution of the classic Visual Basic , which is implemented on the .NET Framework...
working on the DLR has been made by Microsoft on Visual Basic development updates. Similar to C#, Visual Basic would have been able to access objects from dynamic languages built on the DLR such as IronPython
IronPython
IronPython is an implementation of the Python programming language targeting the .NET Framework and Mono. Jim Hugunin created the project and actively contributed to it up until Version 1.0 which was released on September 5, 2006. Thereafter, it was maintained by a small team at Microsoft until...
and IronRuby
IronRuby
IronRuby is an implementation of the Ruby programming language targeting Microsoft .NET framework. It is implemented on top of the Dynamic Language Runtime , a library running on top of the Common Language Infrastructure that provides dynamic typing and dynamic method dispatch, among other things,...
.
IronScheme
IronScheme
IronScheme is an implementation of the Scheme programming language targeting the Microsoft .NET framework. IronScheme is a complete rewrite of IronLisp, incorporating lessons learnt while developing IronLisp....
, an upcoming Scheme implementation, was planning to build upon the DLR. This idea was abandoned because the DLR branch
Branching (software)
Branching, in revision control and software configuration management, is the duplication of an object under revision control so that modifications can happen in parallel along both branches....
the project used became out of sync with the trunk
Trunk (software)
In the field of software development, trunk refers to the unnamed branch of a file tree under revision control. The trunk is usually meant to be the base of a project on which development progresses. If developers are working exclusively on the trunk, it always contains the latest cutting-edge...
, and also because (according to the project coordinator) the current version of the DLR at that time could not support the majority of Scheme's requirements.
Architecture
The Dynamic Language Runtime is built on the idea that it is possible to implement language specificities on top of a generic language-agnostic abstract syntax treeAbstract syntax tree
In computer science, an abstract syntax tree , or just syntax tree, is a tree representation of the abstract syntactic structure of source code written in a programming language. Each node of the tree denotes a construct occurring in the source code. The syntax is 'abstract' in the sense that it...
, whose nodes correspond to a specific functionality that is common to many dynamic languages. This architecture is backed by the idea that the number of elementary language constructs that would have to be implemented on the generic stack should be inherently limited. The DLR dynamically generates code corresponding to the functionality expressed by these nodes. The compiler for any dynamic language implemented on top of the DLR has to generate DLR abstract trees, and hand it over to the DLR libraries.
The DLR provides dynamically-updated
DynamicSite objects that cache the task of binding methods to objects. Since the type of an object—as well as the members it contains—in dynamic languages can change during a program lifetime, a method invocation must check the method list to see if the invocation is a valid one. DynamicSite objects represent and cache the state of the object and its methods; any update to the object is reflected in the DynamicSite objects as well. DLR routes all method invocations via the DynamicSite objects, which then performs a fast lookup and bindingName binding
In programming languages, name binding is the association of objects with identifiers. An identifier bound to an object is said to reference that object. Machine languages have no built-in notion of identifiers, but name-object bindings as a service and notation for the programmer is implemented...
of the method with the actual implementation.
In contrast to other efforts like the Parrot virtual machine
Parrot virtual machine
Parrot is a register-based process virtual machine designed to run dynamic languages efficiently. It uses just-in-time compilation for speed to reduce the interpretation overhead. It is currently possible to compile Parrot assembly language and PIR to Parrot bytecode and execute it...
(with no dependencies) or Da Vinci Machine
Da Vinci Machine
The Da Vinci Machine, also called the Multi Language Virtual Machine is a Sun Microsystems project aiming to prototype the extension of the Java Virtual Machine to add support for dynamic languages....
(built on Java's JVM by adding new bytecodes in the JVM instruction set
Java bytecode
Java bytecode is the form of instructions that the Java virtual machine executes. Each bytecode opcode is one byte in length, although some require parameters, resulting in some multi-byte instructions. Not all of the possible 256 opcodes are used. 51 are reserved for future use...
), the DLR is built on top of the existing Common Language Runtime
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
, the .NET Framework
.NET Framework
The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...
virtual machine.
See also
- Da Vinci MachineDa Vinci MachineThe Da Vinci Machine, also called the Multi Language Virtual Machine is a Sun Microsystems project aiming to prototype the extension of the Java Virtual Machine to add support for dynamic languages....
, an ongoing effort to bring support for dynamic languages on the Java Platform at the Java Virtual MachineJava Virtual MachineA Java virtual machine is a virtual machine capable of executing Java bytecode. It is the code execution component of the Java software platform. Sun Microsystems stated that there are over 4.5 billion JVM-enabled devices.-Overview:...
level.