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61-651: IronPython is written entirely in C# , although some of its code is automatically generated by a code generator written in Python. IronPython is implemented on top of the Dynamic Language Runtime (DLR), a library running on top of the Common Language Infrastructure that provides dynamic typing and dynamic method dispatch, among other things, for dynamic languages. The DLR is part of the .NET Framework 4.0 and

122-584: A JIT compiler, and also because it doesn't have the Global Interpreter Lock . C Sharp (programming language) C# ( / ˌ s iː ˈ ʃ ɑːr p / see SHARP ) is a general-purpose high-level programming language supporting multiple paradigms . C# encompasses static typing, strong typing , lexically scoped , imperative , declarative , functional , generic , object-oriented ( class -based), and component-oriented programming disciplines. The principal inventors of

183-444: A free and open-source project called Mono began, providing a cross-platform compiler and runtime environment for the C# programming language. A decade later, Microsoft released Visual Studio Code (code editor), Roslyn (compiler), and the unified .NET platform (software framework), all of which support C# and are free, open-source, and cross-platform. Mono also joined Microsoft but

244-422: A semitone higher in pitch . This is similar to the language name of C++ , where "++" indicates that a variable should be incremented by 1 after being evaluated. The sharp symbol also resembles a ligature of four "+" symbols (in a two-by-two grid), further implying that the language is an increment of C++. Due to technical limits of display (standard fonts, browsers, etc.), and most keyboard layouts lacking

305-526: A .NET interop. For example, NumPy was wrapped by Microsoft in 2011, allowing code and libraries dependent on it to be run directly from .NET Framework. IronPython is supported on Silverlight (which is deprecated by Microsoft and already has lost support in most web browsers). It can be used as a scripting engine in the browser just like the JavaScript engine. IronPython scripts are passed like simple client-side JavaScript scripts in <script> -tags. It

366-631: A GCC toolchain, macOS for 64-bit Intel and ARM, and Microsoft Windows for 32- and 64-bit Intel. Official tier-2 support exists for Linux for 64-bit ARM, wasm32 ( Web Assembly ) with WASI runtime support, and Linux for 64-bit Intel using a clang toolchain. Official supported tier-3 systems include 64-bit ARM Windows, 64-bit iOS, Raspberry Pi OS (Linux for armv7 with hard float), Linux for 64-bit PowerPC in little-endian mode, and Linux for s390x . More platforms have working implementations, including: PEP 11 lists platforms which are not supported in CPython by

427-420: A backing field, or implement arbitrary getter and setter functions. A property is read-only if there's no setter. Like with fields, there can be class and instance properties. The underlying methods can be virtual or abstract like any other method. Since C# 3.0 the syntactic sugar of auto-implemented properties is available, where the accessor (getter) and mutator (setter) encapsulate operations on

488-419: A class can implement any number of " interfaces " (fully abstract classes). This was a design decision by the language's lead architect to avoid complications and to simplify architectural requirements throughout CLI. When implementing multiple interfaces that contain a method with the same name and taking parameters of the same type in the same order (i.e. the same signature ), similar to Java , C# allows both

549-477: A client to reply, and another may be waiting for a database query to execute, while the third thread is actually processing Python code. However, the GIL does mean that CPython is not suitable for processes that implement CPU-intensive algorithms in Python code that could potentially be distributed across multiple cores. In real-world applications, situations where the GIL is a significant bottleneck are quite rare. This

610-469: A database, parsing an XML file, or searching through a data structure, shifting the emphasis onto the actual program logic to help improve readability and maintainability. C# used to have a mascot called Andy (named after Anders Hejlsberg ). It was retired on January 29, 2004. C# was originally submitted to the ISO/IEC JTC 1 subcommittee SC 22 for review, under ISO/IEC 23270:2003, was withdrawn and

671-484: A factor of five over CPython; this goal was not met. The project was sponsored by Google , and the project owners, Thomas Wouters, Jeffrey Yasskin, and Collin Winter, are full-time Google employees; however, most project contributors were not Google employees. Unladen Swallow was hosted on Google Code . Like many things regarding the Python language, the name Unladen Swallow is a Monty Python reference, specifically to

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732-603: A function (i.e. hiding the former implementation). To do the latter, you have to specify the new keyword. Extension methods in C# allow programmers to use static methods as if they were methods from a class's method table, allowing programmers to virtually add instance methods to a class that they feel should exist on that kind of objects (and instances of the respective derived classes). The type dynamic allows for run-time method binding, allowing for JavaScript-like method calls and run-time object composition . C# has support for strongly-typed function pointers via

793-550: A language other than Python. A particular feature of CPython is that it makes use of a global interpreter lock (GIL) on each CPython interpreter process , which means that within a single process, only one thread may be processing Python bytecode at any one time. This does not mean that there is no point in multithreading ; the most common multithreading scenario is where threads are mostly waiting on external processes to complete. This can happen when multiple threads are servicing separate clients. One thread may be waiting for

854-419: A pointer to the respective object. Due to their special handling of the equality operator, strings will nevertheless behave as if they were values, for all practical purposes. You can even use them as case labels. Where necessary, value types will be boxed automatically. C# supports a strict Boolean data type , bool . Statements that take conditions, such as while and if , require an expression of

915-577: A sharp symbol ( U+266F ♯ MUSIC SHARP SIGN ( &sharp; )), the number sign ( U+0023 # NUMBER SIGN ( &num; )) was chosen to approximate the sharp symbol in the written name of the programming language. This convention is reflected in the ECMA-334 C# Language Specification. The "sharp" suffix has been used by a number of other .NET languages that are variants of existing languages, including J# (a .NET language also designed by Microsoft that

976-434: A single attribute of a class. A C# namespace provides the same level of code isolation as a Java package or a C++ namespace , with very similar rules and features to a package . Namespaces can be imported with the "using" syntax. In C#, memory address pointers can only be used within blocks specifically marked as unsafe , and programs with unsafe code need appropriate permissions to run. Most object access

1037-496: A single method to cover all interfaces and if necessary specific methods for each interface. However, unlike Java, C# supports operator overloading . C# also offers function overloading (a.k.a. ad-hoc-polymorphism). Since version 2.0, C# offers parametric polymorphism , i.e. classes with arbitrary or constrained type parameters, e.g. List<T> , a variable-sized array which only can contain elements of type T . There are certain kinds of constraints you can specify for

1098-508: A special py3k-jit branch of Python's official repository . As of July 2010, this work was ongoing. This merging would have taken some time, since Unladen Swallow was originally based on Python 2.6 with which Python 3 broke compatibility (see Python 3000 for more details). However, the PEP was subsequently withdrawn. In early 2011, it became clear that the project was stopped. Officially supported tier-1 platforms are Linux for 64-bit Intel using

1159-508: A team to build a new language at the time called Cool, which stood for " C-like Object Oriented Language". Microsoft had considered keeping the name "Cool" as the final name of the language, but chose not to do so for trademark reasons. By the time the .NET project was publicly announced at the July 2000 Professional Developers Conference , the language had been renamed C#, and the class libraries and ASP.NET runtime had been ported to C#. Hejlsberg

1220-506: A third-party client-side application developer and passed into the server-side framework through an interface. Note that neither the interface, nor the server-side code is modified to support the analytics required by the client application. In this case, assume that the .NET Framework implements a class, BookDictionary , in a module called BookService , and publishes an interface into which IronPython scripts can be sent and executed. This script, when sent to that interface, will iterate over

1281-611: A type that implements the true operator, such as the Boolean type. While C++ also has a Boolean type, it can be freely converted to and from integers, and expressions such as if (a) require only that a is convertible to bool, allowing a to be an int, or a pointer. C# disallows this "integer meaning true or false" approach, on the grounds that forcing programmers to use expressions that return exactly bool can prevent certain types of programming mistakes such as if (a = b) (use of assignment = instead of equality == ). C#

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1342-685: Is "not a Java clone" and is "much closer to C++" in its design. Since the release of C# 2.0 in November 2005, the C# and Java languages have evolved on increasingly divergent trajectories, becoming two quite different languages. One of the first major departures came with the addition of generics to both languages, with vastly different implementations. C# makes use of reification to provide "first-class" generic objects that can be used like any other class, with code generation performed at class-load time. Furthermore, C# has added several major features to accommodate functional-style programming, culminating in

1403-404: Is C#'s principal designer and lead architect at Microsoft, and was previously involved with the design of Turbo Pascal , Embarcadero Delphi (formerly CodeGear Delphi, Inprise Delphi and Borland Delphi), and Visual J++ . In interviews and technical papers, he has stated that flaws in most major programming languages (e.g. C++ , Java , Delphi , and Smalltalk ) drove the fundamentals of

1464-446: Is a member of a class that can be invoked as a function (a sequence of instructions), rather than the mere value-holding capability of a field (i.e. class or instance variable ). As in other syntactically similar languages, such as C++ and ANSI C , the signature of a method is a declaration comprising in order: any optional accessibility keywords (such as private ), the explicit specification of its return type (such as int , or

1525-532: Is also a part of Mono since version 2.4 from 2009. The DLR can also be used as a library on older CLI implementations. Jim Hugunin created the project and actively contributed to it up until Version 1.0 which was released on September 5, 2006. IronPython 2.0 was released on December 10, 2008. After version 1.0 it was maintained by a small team at Microsoft until the 2.7 Beta 1 release. Microsoft abandoned IronPython (and its sister project IronRuby ) in late 2010, after which Hugunin left to work at Google. The project

1586-440: Is because Python is an inherently slow language and is generally not used for CPU-intensive or time-sensitive operations. Python is typically used at the top level and calls functions in libraries to perform specialized tasks. These libraries are generally not written in Python, and Python code in another thread can be executed while a call to one of these underlying processes takes place. The non-Python library being called to perform

1647-405: Is currently maintained by a group of volunteers at GitHub . There are some differences between the Python reference implementation CPython and IronPython. Some projects built on top of IronPython are known not to work under CPython. Conversely, CPython applications that depend on extensions to the language that are implemented in C are not compatible with IronPython , unless they are implemented in

1708-413: Is derived from Java 1.1), A# (from Ada ), and the functional programming language F# . The original implementation of Eiffel for .NET was called Eiffel#, a name retired since the full Eiffel language is now supported. The suffix has also been used for libraries , such as Gtk# (a .NET wrapper for GTK and other GNOME libraries) and Cocoa# (a wrapper for Cocoa ). The core syntax of

1769-455: Is done through safe object references, which always either point to a "live" object or have the well-defined null value; it is impossible to obtain a reference to a "dead" object (one that has been garbage collected), or to a random block of memory. An unsafe pointer can point to an instance of an unmanaged value type that does not contain any references to objects subject to garbage collections such as class instances, arrays or strings. Code that

1830-740: Is more type safe than C++. The only implicit conversions by default are those that are considered safe, such as widening of integers. This is enforced at compile-time, during JIT , and, in some cases, at runtime. No implicit conversions occur between Booleans and integers, nor between enumeration members and integers (except for literal 0, which can be implicitly converted to any enumerated type). Any user-defined conversion must be explicitly marked as explicit or implicit, unlike C++ copy constructors and conversion operators, which are both implicit by default. C# has explicit support for covariance and contravariance in generic types, unlike C++ which has some degree of support for contravariance simply through

1891-486: Is not marked as unsafe can still store and manipulate pointers through the System.IntPtr type, but it cannot dereference them. Managed memory cannot be explicitly freed; instead, it is automatically garbage collected. Garbage collection addresses the problem of memory leaks by freeing the programmer of responsibility for releasing memory that is no longer needed in most cases. Code that retains references to objects longer than

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1952-550: Is required can still experience higher memory usage than necessary, however once the final reference to an object is released the memory is available for garbage collection. A range of standard exceptions are available to programmers. Methods in standard libraries regularly throw system exceptions in some circumstances and the range of exceptions thrown is normally documented. Custom exception classes can be defined for classes allowing handling to be put in place for particular circumstances as needed. The syntax for handling exceptions

2013-487: Is the reference implementation of the Python programming language . Written in C and Python, CPython is the default and most widely used implementation of the Python language. CPython can be defined as both an interpreter and a compiler as it compiles Python code into bytecode before interpreting it. It has a foreign function interface with several languages, including C, in which one must explicitly write bindings in

2074-482: Is the following: Depending on your plans, the "finally" part can be left out. If error handling is not required, the (Exception ex) parameter can be omitted as well. Also, there can be several "catch" parts handling different kinds of exceptions. Checked exceptions are not present in C# (in contrast to Java). This has been a conscious decision based on the issues of scalability and versionability. Unlike C++ , C# does not support multiple inheritance , although

2135-452: Is then also possible to modify embedded XAML markup. The technology behind this is called Gestalt. The same works for IronRuby . Until version 0.6, IronPython was released under the terms of Common Public License . Following recruitment of the project lead in August 2004, IronPython was made available as part of Microsoft's Shared Source initiative. This license is not OSI -approved but

2196-660: The IEnumerable<;T> interface is implemented on the object. This includes XML documents, an ADO.NET dataset, and SQL databases. + Using LINQ in C# brings advantages like IntelliSense support, strong filtering capabilities, type safety with compile error checking ability, and consistency for querying data over a variety of sources. There are several different language structures that can be utilized with C# and LINQ and they are query expressions, lambda expressions, anonymous types, implicitly typed variables, extension methods, and object initializers. CPython CPython

2257-524: The Common Language Runtime (CLR), which, in turn, drove the design of the C# language. James Gosling , who created the Java programming language in 1994, and Bill Joy , a co-founder of Sun Microsystems , the originator of Java, called C# an "imitation" of Java; Gosling further said that "[C# is] sort of Java with reliability, productivity and security deleted." In July 2000, Hejlsberg said that C#

2318-483: The LINQ extensions released with C# 3.0 and its supporting framework of lambda expressions , extension methods , and anonymous types . These features enable C# programmers to use functional programming techniques, such as closures , when it is advantageous to their application. The LINQ extensions and the functional imports help developers reduce the amount of boilerplate code that is included in common tasks like querying

2379-605: The Python Software Foundation . These platforms can still be supported by external ports. These ports include: External ports not integrated to Python Software Foundation's official version of CPython, with links to its main development site, often include additional modules for platform-specific functionalities, like graphics and sound API for PSP and SMS and camera API for S60. These ports include: These Python versions are distributed with currently-supported enterprise Linux distributions. The support status of Python in

2440-472: The .NET Framework to create a simple Hello World message. The performance characteristics of IronPython compared to CPython , the reference implementation of Python, depends on the exact benchmark used. IronPython performs worse than CPython on most benchmarks taken with the PyStone script but better on other benchmarks. IronPython may perform better in Python programs that use threads or multiple cores, as it has

2501-467: The C# language is similar to that of other C-style languages such as C, C++ and Java, particularly: Some notable features of C# that distinguish it from C, C++, and Java where noted, are: By design, C# is the programming language that most directly reflects the underlying Common Language Infrastructure  (CLI). Most of its intrinsic types correspond to value-types implemented by the CLI framework. However,

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2562-473: The C# programming language were Anders Hejlsberg , Scott Wiltamuth, and Peter Golde from Microsoft . It was first widely distributed in July 2000 and was later approved as an international standard by Ecma (ECMA-334) in 2002 and ISO / IEC (ISO/IEC 23270 and 20619 ) in 2003. Microsoft introduced C# along with .NET Framework and Visual Studio , both of which were closed-source . At the time, Microsoft had no open-source products. Four years later, in 2004,

2623-612: The CPU-intensive task is not subject to the GIL and may concurrently execute many threads on multiple processors without restriction. Concurrency of Python code can only be achieved with separate CPython interpreter processes managed by a multitasking operating system . This complicates communication between concurrent Python processes , though the multiprocessing module mitigates this somewhat; it means that applications that really can benefit from concurrent Python-code execution can be implemented with limited overhead . The presence of

2684-453: The GIL optional from version 3.13 of Python, which is scheduled for release in October 2024. Unladen Swallow was an optimization branch of CPython, intended to be fully compatible and significantly faster. It aimed to achieve its goals by supplementing CPython's custom virtual machine with a just-in-time compiler built using LLVM . The project had stated a goal of a speed improvement by

2745-410: The GIL simplifies the implementation of CPython, and makes it easier to implement multi-threaded applications that do not benefit from concurrent Python code execution. However, without a GIL, multiprocessing apps must make sure all common code is thread safe. Although many proposals have been made to eliminate the GIL, the general consensus has been that in most cases, the advantages of the GIL outweigh

2806-822: The authors claim it meets the open-source definition. With the 2.0 alpha release, the license was changed to the Microsoft Public License , which the OSI has approved. The latest versions are released under the terms of the Apache License 2.0 . One of IronPython's key advantages is in its function as an extensibility layer to application frameworks written in a .NET language. It is relatively simple to integrate an IronPython interpreter into an existing .NET application framework. Once in place, downstream developers can use scripts written in IronPython that interact with .NET objects in

2867-468: The calling site, and you can choose between ref and out , the latter allowing handing over an uninitialized variable which will have a definite value on return. Additionally, you can specify a variable-sized argument list by applying the params keyword to the last parameter. Certain specific kinds of methods, such as those that simply get or set a field's value by returning or assigning it, do not require an explicitly stated full signature, but in

2928-416: The disadvantages; in the few cases where the GIL is a bottleneck, the application should be built around the multiprocessing structure. To help allow more parallelism, an improvement was released in October 2023 to allow a separate GIL per subinterpreter in a single Python process and have been described as "threads with opt-in sharing". After several debates, a project was launched in 2023 to propose making

2989-492: The entire list of books maintained by the framework, and pick out those written by Booker Prize-winning authors. What's interesting is that the responsibility for writing the actual analytics reside with the client-side developer. The demands on the server-side developer are minimal, essentially just providing access to the data maintained by the server. This design pattern greatly simplifies the deployment and maintenance of complex application frameworks. The following script uses

3050-523: The framework, thereby extending the functionality in the framework's interface, without having to change any of the framework's code base. IronPython makes extensive use of reflection . When passed in a reference to a .NET object, it will automatically import the types and methods available to that object. This results in a highly intuitive experience when working with .NET objects from within an IronPython script. The following IronPython script manipulates .NET Framework objects. This script can be supplied by

3111-404: The general case, the definition of a class includes the full signature declaration of its methods. Like C++, and unlike Java, C# programmers must use the scope modifier keyword virtual to allow methods to be overridden by subclasses. Unlike C++, you have to explicitly specify the keyword override when doing so. This is supposed to avoid confusion between overriding and newly overloading

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3172-838: The joke about the airspeed velocity of unladen swallows in Monty Python and the Holy Grail . Although it fell short of all published goals, Unladen Swallow did produce some code that got added to the main Python implementation, such as improvements to the cPickle module. In July 2010, some observers speculated on whether the project was dead or dying since the 2009 Q4 milestone had not yet been released. The traffic on Unladen's mailing list had decreased from 500 messages in January 2010 to fewer than 10 in September 2010. It has also been reported that Unladen lost Google's funding. In November 2010, one of

3233-523: The keyword delegate . Like the Qt framework's pseudo-C++ signal and slot , C# has semantics specifically surrounding publish-subscribe style events, though C# uses delegates to do so. C# offers Java-like synchronized method calls, via the attribute [MethodImpl(MethodImplOptions.Synchronized)] , and has support for mutually-exclusive locks via the keyword lock . C# supports classes with properties . The properties can be simple accessor functions with

3294-402: The keyword var , and implicitly typed arrays with the keyword new[] followed by a collection initializer. Its type system is split into two families: Value types, like the built-in numeric types and user-defined structs, which are automatically handed over as copies when used as parameters, and reference types, including arrays, instances of classes, and strings, which only hand over

3355-403: The keyword void if no value is returned), the name of the method, and finally, a parenthesized sequence of comma-separated parameter specifications, each consisting of a parameter's type, its formal name and optionally, a default value to be used whenever none is provided. Different from most other languages, call-by-reference parameters have to be marked both at the function definition and at

3416-432: The language specification does not state the code generation requirements of the compiler: that is, it does not state that a C# compiler must target a Common Language Runtime, or generate Common Intermediate Language (CIL), or generate any other specific format. Some C# compilers can also generate machine code like traditional compilers of C++ or Fortran . C# supports strongly, implicitly typed variable declarations with

3477-421: The main developers announced that "Jeffrey and I have been pulled on to other projects of higher importance to Google." The 2009 Q4 development branch was created on 26 January 2010, but no advertising was made on the website. Further, regarding the long-term plans, and as the project missed the Python 2.7 release, a Python Enhancement Proposal (PEP) was accepted, which proposed a merge of Unladen Swallow into

3538-473: The semantics of return types on virtual methods. Enumeration members are placed in their own scope . The C# language does not allow for global variables or functions. All methods and members must be declared within classes. Static members of public classes can substitute for global variables and functions. Local variables cannot shadow variables of the enclosing block, unlike C and C++. Metaprogramming can be achieved in several ways: A method in C#

3599-413: The type parameters: Has to be type X ( or one derived from it ), has to implement a certain interface, has to be a reference type, has to be a value type, has to implement a public parameterless constructor . Most of them can be combined, and you can specify any number of interfaces. C# has the ability to utilize LINQ through the .NET Framework. A developer can query a variety of data sources, provided

3660-416: Was not merged into .NET. As of November 2024, the most recent stable version of the language is C# 13.0, which was released in 2024 in .NET 9.0. The Ecma standard lists these design goals for C#: During the development of the .NET Framework , the class libraries were originally written using a managed code compiler system named Simple Managed C (SMC). In January 1999, Anders Hejlsberg formed

3721-429: Was then approved under ISO/IEC 23270:2006. The 23270:2006 is withdrawn under 23270:2018 and approved with this version. Microsoft first used the name C# in 1988 for a variant of the C language designed for incremental compilation. That project was not completed, and the name was later reused. The name "C sharp" was inspired by the musical notation whereby a sharp symbol indicates that the written note should be made

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