computer programming Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as ana ...

, Intentional Programming is a

programming paradigm Programming paradigms are a way to classify programming languages based on their features. Languages can be classified into multiple paradigms. Some paradigms are concerned mainly with implications for the execution model of the language, suc ...

developed by

Charles Simonyi Charles Simonyi (; hu, Simonyi Károly, ; born September 10, 1948) is a Hungarian-American software architect. He started and led Microsoft's applications group, where he built the first versions of Microsoft Office. He co-founded and led In ...

that encodes in software

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

the precise ''intention'' which programmers (or users) have in mind when conceiving their work. By using the appropriate level of

abstraction Abstraction in its main sense is a conceptual process wherein general rules and concepts are derived from the usage and classification of specific examples, literal ("real" or "concrete") signifiers, first principles, or other methods. "An abstr ...

at which the programmer is thinking, creating and maintaining

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program ...

s become easier. By separating the concerns for intentions and how they are being operated upon, the software becomes more modular and allows for more reusable software code. ''Intentional Programming'' was developed by former

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...

chief architect

, who led a team in

Microsoft Research Microsoft Research (MSR) is the research subsidiary of Microsoft. It was created in 1991 by Richard Rashid, Bill Gates and Nathan Myhrvold with the intent to advance state-of-the-art computing and solve difficult world problems through technologi ...

, which developed the paradigm and built an

integrated development environment An integrated development environment (IDE) is a software application that provides comprehensive facilities to computer programmers for software development. An IDE normally consists of at least a source code editor, build automation tools a ...

(IDE) called IP (for Intentional Programming) that demonstrated the paradigm. Microsoft decided not to productize the Intentional Programming paradigm, as in the early 2000s Microsoft was rolling out C# and .NET to counter Java adoption."Simonyi explains, 'It was impractical, when Microsoft was making tremendous strides with .Net in the near term, to somehow send somebody out from the same organization who says, "This is not how you should do things--what if you did things in this other, more disruptive way?'" (Quote fro
"Anything You Can Do, I Can Do Meta"
Tuesday, January 9, 2007, Scott Rosenberg, ''

Technology Review ''MIT Technology Review'' is a bimonthly magazine wholly owned by the Massachusetts Institute of Technology, and editorially independent of the university. It was founded in 1899 as ''The Technology Review'', and was re-launched without "The" in ...

''. ) Charles Simonyi decided, with approval of Microsoft, to take his idea out from Microsoft and commercialize it himself. He founded the company Intentional Software to pursue this. Microsoft licensed the Intentional Programming patents Simonyi had acquired while at Microsoft, but no source code, to Intentional Software. An overview of Intentional Programming as it was developed at Microsoft Research is given in Chapter 11 of the book ''Generative Programming: Methods, Tools, and Applications''.

Development cycle

As envisioned by Simonyi, developing a new application via the Intentional Programming paradigm proceeds as follows. A programmer builds a

WYSIWYG In computing, WYSIWYG ( ), an acronym for What You See Is What You Get, is a system in which editing software allows content to be edited in a form that resembles its appearance when printed or displayed as a finished product, such as a printed d ...

-like environment supporting the schema and notation of business knowledge for a given problem domain (such as productivity applications or life insurance). Users then use this environment to capture their intentions, which are recorded at high level of abstraction. The environment can operate on these intentions and assist the user to create semantically richer documents that can be processed and executed, similar to a

spreadsheet A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cel ...

. The recorded knowledge is executed by an evaluator or is compiled to generate the final program. Successive changes are done at the WYSIWYG level only. As opposed to word processors, spreadsheets or presentation software, an Intentional environment has more support for structure and semantics of the intentions to be expressed, and can create interactive documents that capture more richly what the user is trying to accomplish. A special case is when the content is

program code A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Construction language – all forms of communication by which a human can specify an executable problem solution to a comput ...

, and the environment becomes an intelligent IDE.Scott Rosenberg:
Anything You Can Do, I Can Do Meta
" ''

'', January 8, 2007.

Separating source code storage and presentation

Key to the benefits of Intentional Programming is that domain code which capture the intentions are not stored in source code

text file A text file (sometimes spelled textfile; an old alternative name is flatfile) is a kind of computer file that is structured as a sequence of lines of electronic text. A text file exists stored as data within a computer file system. In operating ...

s, but in a tree-based storage (could be binary or XML). Tight integration of the environment with the storage format brings some of the nicer features of

database normalization Database normalization or database normalisation (see spelling differences) is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. ...

. Redundancy is eliminated by giving each

definition A definition is a statement of the meaning of a term (a word, phrase, or other set of symbols). Definitions can be classified into two large categories: intensional definitions (which try to give the sense of a term), and extensional definitio ...

a unique

identity Identity may refer to: * Identity document * Identity (philosophy) * Identity (social science) * Identity (mathematics) Arts and entertainment Film and television * ''Identity'' (1987 film), an Iranian film * ''Identity'' (2003 film), ...

, and storing the name of variables and operators in exactly one place. This makes it easier to intrinsically distinguish declarations from

reference Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to ''refer to'' the second object. It is called a ''name'' ...

s, and the environment can show them differently. Whitespace in a program is also not stored as part of the

, and each programmer working on a project can choose an

indentation __FORCETOC__ In the written form of many languages, an indentation or indent is an empty space at the beginning of a line to signal the start of a new paragraph. Many computer languages have adopted this technique to designate "paragraphs" or o ...

display of the source. More radical visualizations include showing statement lists as nested boxes, editing

conditional expressions Conditional (if then) may refer to: *Causal conditional, if X then Y, where X is a cause of Y *Conditional probability, the probability of an event A given that another event B has occurred *Conditional proof, in logic: a proof that asserts a co ...

logic gate A logic gate is an idealized or physical device implementing a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, ...

s, or re-rendering names in Chinese. The system uses a normalized language for popular languages like

C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...

and

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

, while letting users of the environment mix and match these with ideas from

Eiffel Eiffel may refer to: Places * Eiffel Peak, a summit in Alberta, Canada * Champ de Mars – Tour Eiffel station, Paris, France; a transit station Structures * Eiffel Tower, in Paris, France, designed by Gustave Eiffel * Eiffel Bridge, Ungheni, M ...

and other languages. Often mentioned in the same context as

language-oriented programming Language-oriented programming (LOP) is a software-development paradigm where "language" is a software building block with the same status as objects, modules and components, and rather than solving problems in general-purpose programming languages, ...

via

domain-specific language A domain-specific language (DSL) is a computer language specialized to a particular application domain. This is in contrast to a general-purpose language (GPL), which is broadly applicable across domains. There are a wide variety of DSLs, ranging f ...

s, and

aspect-oriented programming In computing, aspect-oriented programming (AOP) is a programming paradigm that aims to increase modularity by allowing the separation of cross-cutting concerns. It does so by adding behavior to existing code (an advice) ''without'' modifying t ...

, IP purports to provide some breakthroughs in

generative programming In computer science, the term automatic programming identifies a type of computer programming in which some mechanism generates a computer program to allow human programmers to write the code at a higher abstraction level. There has been little ...

. These techniques allow developers to extend the language environment to capture domain-specific constructs without investing in writing a full

compiler In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...

and editor for any new languages.

Programming Example

program that writes out the numbers from 1 to 10, using a

curly bracket A bracket is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. Typically deployed in symmetric pairs, an individual bracket may be identified as a 'left' or 'r ...

syntax, might look like this: for (int i = 1; i <= 10; i++) The code above contains a common construct of most

programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...

s, the bounded loop, in this case represented by the for construct. The code, when compiled, linked and run, will loop 10 times, incrementing the value of ''i'' each time after printing it out. But this code does not capture the ''intentions'' of the programmer, namely to "print the numbers 1 to 10". In this simple case, a programmer asked to maintain the code could likely figure out what it is intended to do, but it is not always so easy. Loops that extend across many lines, or pages, can become very difficult to understand, notably if the original programmer uses unclear labels. Traditionally the only way to indicate the intention of the code was to add

source code comment In computer programming, a comment is a programmer-readable explanation or ''annotation'' in the source code of a computer program. They are added with the purpose of making the source code easier for humans to understand, and are generally igno ...

s, but often comments are not added, or are unclear, or drift out of sync with the source code they originally described. In intentional programming systems the above loop could be represented, at some level, as something as obvious as "print the numbers 1 to 10". The system would then use the intentions to generate source code, likely something very similar to the code above. The key difference is that the intentional programming systems maintain the semantic level, which the source code lacks, and which can dramatically ease

readability Readability is the ease with which a reader can understand a written text. In natural language, the readability of text depends on its content (the complexity of its vocabulary and syntax) and its presentation (such as typographic aspects that a ...

in larger programs. Although most languages contain mechanisms for capturing certain kinds of

, IP, like the Lisp family of languages, allows for the addition of entirely new mechanisms. Thus, if a developer started with a language like C, they would be able to extend the language with features such as those in C++ without waiting for the compiler developers to add them. By analogy, many more powerful expression mechanisms could be used by programmers than mere classes and

procedures Procedure may refer to: * Medical procedure * Instructions or recipes, a set of commands that show how to achieve some result, such as to prepare or make something * Procedure (business), specifying parts of a business process * Standard opera ...

Identity

IP focuses on the concept of

. Since most programming languages represent the source code as

plain text In computing, plain text is a loose term for data (e.g. file contents) that represent only characters of readable material but not its graphical representation nor other objects (floating-point numbers, images, etc.). It may also include a limit ...

objects Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an ...

are defined by names, and their uniqueness has to be inferred by the

. For example, the same symbolic name may be used to name different variables, procedures, or even types. In code that spans several pages – or, for globally visible names, multiple files – it can become very difficult to tell what

symbol A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...

refers to what actual object. If a name is changed, the code where it is used must carefully be examined. By contrast, in an IP system, all

s not only assign symbolic names, but also unique private

identifier An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, physical countable object (or class thereof), or physical noncountable ...

s to objects. This means that in the IP development environment, every reference to a variable or procedure is not just a name – it is a link to the original entity. The major advantage of this is that if an entity is renamed, all of the references to it in the program remain valid (known as

referential integrity Referential integrity is a property of data stating that all its references are valid. In the context of relational databases, it requires that if a value of one attribute (column) of a relation (table) references a value of another attribute (ei ...

). This also means that if the same name is used for unique definitions in different

namespaces In computing, a namespace is a set of signs (''names'') that are used to identify and refer to objects of various kinds. A namespace ensures that all of a given set of objects have unique names so that they can be easily identified. Namespaces ...

(such as ".to_string()"), references with the same name but different identity will not be renamed, as sometimes happens with search/replace in current editors. This feature also makes it easy to have multi-language versions of the program; it can have a set of English-language names for all the definitions as well as a set of Japanese-language names which can be swapped in at will. Having a unique identity for every defined object in the program also makes it easy to perform automated

refactoring In computer programming and software design, code refactoring is the process of restructuring existing computer code—changing the '' factoring''—without changing its external behavior. Refactoring is intended to improve the design, structu ...

tasks, as well as simplifying code check-ins in versioning systems. For example, in many current code

collaboration system Collaboration (from Latin ''com-'' "with" + ''laborare'' "to labor", "to work") is the process of two or more people, entities or organizations working together to complete a task or achieve a goal. Collaboration is similar to cooperation. Most ...

s (e.g.

Git Git () is a distributed version control system: tracking changes in any set of files, usually used for coordinating work among programmers collaboratively developing source code during software development. Its goals include speed, data in ...

), when two programmers commit changes that conflict (i.e. if one programmer renames a function while another changes one of the lines in that function), the versioning system will think that one programmer created a new function while another modified an old function. In an IP versioning system, it will know that one programmer merely changed a name while another changed the code.

Levels of detail

IP systems also offer several levels of detail, allowing the programmer to "zoom in" or out. In the example above, the programmer could zoom out to get a level that would say something like: <> Thus IP systems are

self-documenting In computer programming, self-documenting (or self-describing) source code and user interfaces follow naming conventions and structured programming conventions that enable use of the system without prior specific knowledge. In web development, se ...

to a large degree, allowing the programmer to keep a good high-level picture of the program as a whole.

Similar works

There are projects that exploit similar ideas to create code with higher level of abstraction. Among them are: *

Concept programming Christophe de Dinechin is a French computer scientist, with contributions in video games, programming languages and operating systems. Programming languages Dinechin contributed to C++, notably a high-performance exception handling implementati ...

Language-oriented programming Language-oriented programming (LOP) is a software-development paradigm where "language" is a software building block with the same status as objects, modules and components, and rather than solving problems in general-purpose programming languages, ...

(LOP) **

Domain-specific language A domain-specific language (DSL) is a computer language specialized to a particular application domain. This is in contrast to a general-purpose language (GPL), which is broadly applicable across domains. There are a wide variety of DSLs, ranging f ...

(DSL) *

Program transformation A program transformation is any operation that takes a computer program and generates another program. In many cases the transformed program is required to be semantically equivalent to the original, relative to a particular formal semantics and ...

* Semantic-oriented programming (SOP) *

Literate programming Literate programming is a programming paradigm introduced in 1984 by Donald Knuth in which a computer program is given as an explanation of its logic in a natural language, such as English, interspersed (embedded) with snippets of macros and t ...

Model-driven architecture Model Driven Architecture (MDA) is a software design approach for the development of software systems. It provides a set of guidelines for the structuring of specifications, which are expressed as models. Model Driven Architecture is a kind of doma ...

(MDA) *

Software factory A software factory is a structured collection of related software assets that aids in producing computer software applications or software components according to specific, externally defined end-user requirements through an assembly process. A s ...

Metaprogramming Metaprogramming is a programming technique in which computer programs have the ability to treat other programs as their data. It means that a program can be designed to read, generate, analyze or transform other programs, and even modify itself ...

Lisp (programming language) Lisp (historically LISP) is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in 1960, Lisp is the second-oldest high-level programming language still in common us ...

References

{{reflist

External links

Intentional Software
- Charles Simonyi's company
''The Death Of Computer Languages, The Birth of Intentional Programming'', a technical report by Charles Simonyi (1995)

* ttp://www.edge.org/digerati/simonyi/simonyi_p2.html Edge.org interview with Charles Simonyi (interviewer: John Brockman)
Language Workbenches: The Killer-App for Domain Specific Languages?
- Martin Fowler's article on the general class of tools that Intentional Programming is an example of.
"Anything You Can Do, I Can Do Meta"
Tuesday, January 9, 2007, Scott Rosenberg, ''

''
Awaiting the Day When Everyone Writes Software
''The New York Times'', 28 January 2007
''Is programming a form of encryption?'', by Charles Simonyi (2005)

''Appropriate Levels of Abstraction'', by Charles Simonyi (2005)

''The information contents of programs'', by Charles Simonyi (2005)

''Feature X Considered Harmful'', by Charles Simonyi (2005)

''Notations and Programming Languages'', by Charles Simonyi (2005)

''Personal Observations from a Developer'', by Mark Edel (2005)

Microsoft Research's educational video introducing their Intentional Programming system
(ASF format, circa 1998, 20 megabytes) Programming paradigms