{{no references, date=March 2013
The "-P Convention" or "P Question" refers to the act of making a statement into a question by appending "P." When spoken aloud, the "P" is literally pronounced as a separate syllable "Pee."
This practice originated among users of the
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 u ...
, in which there is
the convention of appending the letter "P" on elements to denote a
predicate
Predicate or predication may refer to:
* Predicate (grammar), in linguistics
* Predication (philosophy)
* several closely related uses in mathematics and formal logic:
**Predicate (mathematical logic)
**Propositional function
**Finitary relation, o ...
(a yes or no question). It is most commonly used at
MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
and the
University of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
, or among computer scientists working in
Artificial intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech r ...
(which frequently uses Lisp).
This usage was immortalized in the Jargon File and from there the use spread to some younger users seeking to be part of the classical
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
community.
The typical example of use is:
Q: "Foodp?" (Do you want food?)
A: "T!" (Literally, True: yes)
A: "Nil." (Also Null; no, I don't want food).
See also
*
M-expression
In computer programming, M-expressions (or meta-expressions) were an early proposed syntax for the Lisp programming language, inspired by contemporary languages such as Fortran and ALGOL. The notation was never implemented into the language and, ...
and
S-expression
In computer programming, an S-expression (or symbolic expression, abbreviated as sexpr or sexp) is an expression in a like-named notation for nested list (tree-structured) data. S-expressions were invented for and popularized by the programming la ...
were other new information representations introduced in a related context.