Obliq is an interpreted,

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of '' objects''. Objects can contain data (called fields, attributes or properties) and have actions they can perform (called procedures or methods and impleme ...

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

designed to make

distributed Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

, and locally multithreaded, computing simpler and easier to program, while providing program safety and an implicit type system. The interpreter is written in

Modula-3 Modula-3 is a programming language conceived as a successor to an upgraded version of Modula-2 known as Modula-2+. It has been influential in research circles (influencing the designs of languages such as Java, C#, Python and Nim), but it ha ...

, and provides Obliq with full access to Modula-3's

network Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematics ...

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 ai ...

abilities. A

type inference Type inference, sometimes called type reconstruction, refers to the automatic detection of the type of an expression in a formal language. These include programming languages and mathematical type systems, but also natural languages in some bran ...

algorithm for record concatenation, subtyping, and recursive types has been developed for Obliq. Further, it has been proved to be

NP-complete In computational complexity theory, NP-complete problems are the hardest of the problems to which ''solutions'' can be verified ''quickly''. Somewhat more precisely, a problem is NP-complete when: # It is a decision problem, meaning that for any ...

and its lowest complexity to be or if under other modeling up to certain conditions down to and its best known implementation runs in . Obliq's syntax is very similar to Modula-3, the biggest difference being that Obliq has no need of explicit typed

variables Variable may refer to: Computer science * Variable (computer science), a symbolic name associated with a value and whose associated value may be changed Mathematics * Variable (mathematics), a symbol that represents a quantity in a mathemat ...

(i.e., a variable can hold any

data type In computer science and computer programming, a data type (or simply type) is a collection or grouping of data values, usually specified by a set of possible values, a set of allowed operations on these values, and/or a representation of these ...

allowed by the type checker and if does not accepts one, i.e., a given expression execution error will display) although explicit type declarations are allowed and ignored by the interpreter. The basic data types in the language include booleans,

integers An integer is the number zero (0), a positive natural number (1, 2, 3, ...), or the negation of a positive natural number (−1, −2, −3, ...). The negations or additive inverses of the positive natural numbers are referred to as negative in ...

, reals,

characters Character or Characters may refer to: Arts, entertainment, and media Literature * ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk * ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to Theoph ...

strings String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other objects Arts, entertainment, and media Films * ''Strings'' (1991 film), a Canadian anim ...

, and

arrays An array is a systematic arrangement of similar objects, usually in rows and columns. Things called an array include: {{TOC right Music * In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the ...

. Obliq supports the usual set of sequential

control structures In computer science, control flow (or flow of control) is the order in which individual statements, instructions or function calls of an imperative program are executed or evaluated. The emphasis on explicit control flow distinguishes an '' ...

(conditional, iteration, and exception handling forms), and special control forms for concurrency (mutexes and guarded statements). Further, Obliq's objects can be cloned and safely copied remotely by any machine in a distributed network object and it can be done safely and transparently. Obliq's large

standard library In computer programming, a standard library is the library (computing), library made available across Programming language implementation, implementations of a programming language. Often, a standard library is specified by its associated program ...

provides strong support for mathematical operations,

input/output In computing, input/output (I/O, i/o, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, such as another computer system, peripherals, or a human operator. Inputs a ...

(I/O),

persistence Persistence or Persist may refer to: Math and computers * Image persistence, in LCD monitors * Persistence (computer science), the characteristic of data that outlives the execution of the program that created it * Persistence of a number, a ma ...

, thread control, graphics, and animation. Distributed computing is object-based: objects hold a state, which is local to one

process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management * Business process, activities that produce a specific s ...

. Scope of objects and other variables is purely

lexical Lexical may refer to: Linguistics * Lexical corpus or lexis, a complete set of all words in a language * Lexical item, a basic unit of lexicographical classification * Lexicon, the vocabulary of a person, language, or branch of knowledge * Lexical ...

. Objects can call methods of other objects, even if those objects are on another machine on the network. Obliq objects are simply collections of named fields (similar to slots in

Self In philosophy, the self is an individual's own being, knowledge, and values, and the relationship between these attributes. The first-person perspective distinguishes selfhood from personal identity. Whereas "identity" is (literally) same ...

and

Smalltalk Smalltalk is a purely object oriented programming language (OOP) that was originally created in the 1970s for educational use, specifically for constructionist learning, but later found use in business. It was created at Xerox PARC by Learni ...

), and support

inheritance Inheritance is the practice of receiving private property, titles, debts, entitlements, privileges, rights, and obligations upon the death of an individual. The rules of inheritance differ among societies and have changed over time. Offi ...

by delegation (like Self). The common uses of Obliq involve programming over networks, 3D animation, and distributed computing, as occurs over a

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...

(LAN) such as

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

. Obliq is included free with the

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

(DEC) Modula-3 distribution, but other free versions exist elsewhere including precompiled binaries for several

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

Projects using Obliq

*The ''Collaborative Active Textbooks'' (CAT) developed using Obliq applets and the ZeusZeus: A System for Algorithm Animation and Multi-view Editing
Marc H. Brown.

(DEC)

Systems Research Center The Systems Research Center (SRC) was a research laboratory created by Digital Equipment Corporation (DEC) in 1984, in Palo Alto, California. DEC SRC was founded by a group of computer scientists, led by Robert Taylor, who left the Computer ...

(SRC) Research Report 075 (February 1992) algorithm animation System (written in

). *Obliq applets (Oblets) special web browser (written in

) Obliq web page embedded applications.

References

External links

* *

Luca Cardelli Luca Andrea Cardelli is an Italian computer scientist who is a research professor at the University of Oxford, UK. Cardelli is well known for his research in type theory and operational semantics. Among other contributions, in programming lang ...

'
Obliq Quick Start
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