Science Fair Project Encyclopedia
Esoteric programming language
Among some hackers and hobbyists, an esoteric programming language is a programming language designed as a test of the boundaries of computer programming language design, as a proof of concept, or as joke, and not with the intention of being adopted for real-world programming. 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.
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. Utilizing a counterintuitive set of operations and a character set full of awkward constructions, INTERCAL is a classic example of what are now known as write-only imperative, or despotic, programming languages.
More than twenty years later, Urban Müller created the now famous Brainfuck, which with only eight recognized characters, is considered the canonical example of a Turing tarpit. 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 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 ).
- Turning tarpit (sic)
- A highly minimalist despotic language in which the only way to select an operation is by moving along a list of stateful encodings. This was coined as the result of a Freudian slip while discussing the despotic language Whirl.
- Category:Esoteric programming languages provides an automated exhaustive list.
- List of esoteric programming languages is a manually-made list.
There is a small but thriving community on the Internet of hobbyists who program in and design esoteric programming languages. Their main form of correspondence is through the esoteric languages mailing list, email@example.com. One can subscribe to the list by sending a mail with subscribe lang as the message body to firstname.lastname@example.org.
There is also a secondary and more directed list, email@example.com, which is specifically geared to Brainfuck related pursuits.
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.
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.
- The Esoteric Programming Languages Webring
- DM's Esoteric Programming Languages
- ESOTERIC programming languages
- alt.lang.intercal (Usenet group for Intercal, discussing all esoteric programming languages)
- #esoteric on freenode IRC network
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