Esoteric programming language
Categories: Esoteric programming languages
An esoteric programming language (sometimes shortened to esolang) is a programming language designed as a test of the boundaries of computer programming language design, as a proof of concept, or as a joke, and not with the intention of being adopted for real-world programming. Such languages are often popular among hackers and hobbyists. This use of esoteric is meant to distinguish these languages from more popular programming languages, such as the APL programming language, that may appear esoteric (in the usual sense of the word) to some, although these are arguably "esoteric programming languages" too.
Usability is rarely a high priority for such languages. The usual aim is to remove or replace conventional language features while still maintaining a language that is Turing-complete. Thus, by adhering to some principles while deliberately making no sense as a whole, these languages are perhaps the programming equivalent of nonsense verse.
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History
The earliest, and still the canonical, esoteric language was INTERCAL, designed in 1972 by James Lyons and Don Woods, with the stated intention of being unlike any other programming language the authors were familiar with.
More than twenty years later, Urban Müller created the now famous Brainfuck, which consist of only eight recognized characters. Along with Befunge, Brainfuck is now one of the most well-supported esoteric programming languages, and it is no surprise that both are highly valued as they were both the first of their respective kinds and still the most elegant.
Esoteric programming terms
Turing tarpit
A Turing-complete programming language with arbitrarily few commands. These include Brainfuck (8 commands, all with 0 operands), OISC (1 command, 3 operands), and Thue (1 command, 2 operands).
Language paradigm
The paradigm of a language can fall into a number of categories, and these categories are used to get a general understanding of the way that a specific language operates. These include imperative/despotic languages such as Brainfuck, in which instructions describe how to change data; functional languages such as Unlambda, in which data and code are more or less interchangeable and execution is the repeated application of functions to the results of other functions; and rewriting languages such as Thue, in which transformation functions are applied to an initial state.
Deterministic language
A deterministic language is one in which it can always be predicted based on the state of a program what the next state will be. Most languages are deterministic, as nondeterministic languages such as Java2K often give unreliable results, and getting even trivial programs to have a reliable output is often a monumental task.
Despotic language
A despotic language is a Turing tarpit with a stateful encoding, namely a language in which commands are used to select from a finite range of operations and apply these operations to the current state of the program. Examples include ReMorse and Whirl, and arguably Intercal.
Stateful encoding
A system of encoding programs such that each substring of the encoding is an instruction to locate the next instruction in a list. An example based on ReMorse or THRAT would be:
- Select Next Operation in list
- Perform Operation
With the list of operations either standard (as in ReMorse or THRAT) or dynamic (as in ReMorse4ever).
Example languages
The canonical esoteric languages are probably Intercal, Brainfuck, and Befunge.
- Category:Esoteric programming languages provides an automated exhaustive list.
- List of esoteric programming languages is a manually-made list.
- More esolangs can be found on the esolang wiki's language list.
Internet community
There is a small but thriving community on the Internet of hobbyists who program in and design esoteric programming languages.
The esolang community is active sporadically, and topics of discussion range from debate as to whether or not a language is Turing-complete to how one would go about representing abstract and hard to visualise mathematical concepts in a programming environment. There is a mailing list, but as of 2005 the mailing list is nearly abandoned and most discussion happens on the wiki (see below).
Turing completeness is a favorite topic of discussion, since it is not immediately obvious whether or not a language is Turing complete, and it often takes rather large intuitive leaps to come to a solution. New languages with new features are always being created, so proof of Turing completeness is always a challenge.
A related pursuit among programming language enthusiasts is the writing of obfuscated code.
External links
es:Lenguaje de programación esotérico fr:Langage de programmation exotique ko:난해한 프로그래밍 언어 ru:Эзотерические языки программирования