Obliq is an interpreted,

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of pro ...

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 ...

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+. While it has been influential in research circles (influencing the designs of languages such as Java, C#, and Python) it has not be ...

, 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 ...

abilities. A

type inference Type inference 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 branches of computer science and linguistics ...

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, a problem is NP-complete when: # it is a problem for which the correctness of each solution can be verified quickly (namely, in polynomial time) and a brute-force search algorithm can find a solution by tryi ...

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 (i.e., a variable can hold any

data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allowed operations on it. A data type tells the compiler or interpreter how the programmer intends to use the data. Most progra ...

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 (), a positive natural number (, , , etc.) or a negative integer with a minus sign (−1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language o ...

, 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 The ...

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 ''imper ...

(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 made available across implementations of a programming language. These libraries are conventionally described in programming language specifications; however, contents of a language's as ...

provides strong support for mathematical operations,

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

(I/O), persistence, 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 se ...

. 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 The self is an individual as the object of that individual’s own reflective consciousness. Since the ''self'' is a reference by a subject to the same subject, this reference is necessarily subjective. The sense of having a self—or ''selfhood ...

and

Smalltalk Smalltalk is an object-oriented, dynamically typed reflective programming language. It was designed and created in part for educational use, specifically for constructionist learning, at the Learning Research Group (LRG) of Xerox PARC by Alan Ka ...

), and support

inheritance Inheritance is the practice of receiving private property, Title (property), titles, debts, entitlements, Privilege (law), privileges, rights, and Law of obligations, obligations upon the death of an individual. The rules of inheritance differ ...

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, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger ...

(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 unt ...

(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, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

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

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

) Obliq web page embedded applications.http://www.ibiblio.org/openvideo/video/chi/chi97_02_m1.mpg

References

External links

* * *

Luca Cardelli Luca Andrea Cardelli, Fellow of the Royal Society (FRS), is an Italian computer scientist who is a research professor at the University of Oxford in Oxford, UK. Cardelli is well known for his research in type theory and operational semantics. A ...

'
Obliq Quick Start
page (archived on 2008-10-17) {{Modula, Oberon Modula programming language family Oberon programming language family Prototype-based programming languages Procedural programming languages Systems programming languages Programming languages created in 1993 Dynamically typed programming languages