HQ9+

HQ9+ is a joke language with four instructions:

• H: Print "hello, world"
• Q: Print the program's source code
• 9: Print the lyrics to "99 Bottles of Beer"
• +: Increment the accumulator

Although the language is not of serious interest by itself, it can be useful to implement HQ9+ in a new esoteric programming language, since doing so proves that all the tasks above, except the quine, are possible. HQ9+ was created by Cliff L. Biffle.

See also

• HQ9++, an object-oriented extension of HQ9+.
• CHIQRSX9+, another HQ9+ extension.
• HQ9+B, an ℒ-complete extension of HQ9+.
• HQ9+2D, a 2-D extension of HQ9+.
• H9+, with one fewer instruction but still capable of all of the tasks.

External resources

• HQ9+ home page (from the Wayback Machine; retrieved on 2 June 2009)
• HQ9+ as an embedded language in Haskell
• Online HQ9+ interpreter in JavaScript
• Online HQ9+ interpreter realized with PHP
• HQ9+ interpreter in C
• HQ9+ interpreter in Pascal by User:GrandKeyboard
• hq9plus - HQ9P implementation for Parrot