P′′ (P double prime[1]) is a primitive computer programming language created by Corrado Böhm[2][3] in 1964 to describe a family of Turing machines.



P (hereinafter written P′′) is formally defined as a set of words on the four-instruction alphabet.

Relation to other programming languages

  • P′′ was the first “GOTO-less” imperative structured programming language to be proven Turing-complete[2][3]
  • The Brainfuck language (apart from its I/O commands) is a minor informal variation of P′′. Böhm gives explicit P′′ programs for each of a set of basic functions sufficient to compute any computable function, using only {\textstyle (}, {\textstyle )}and the four Example program[edit]

Böhm[2] gives the following program to compute the predecessor (x-1) of an integer x > 0:

which translates directly to the equivalent Brainfuck program:


The program expects an integer to be represented in bijective base-k notation.


  1. ^https://github.com/Pbtflakes/pdbl
  2. ^ Jump up to:ab c Böhm, C.: “On a family of Turing machines and the related programming language”, ICC Bull. 3, 185-194, July 1964.
  3. ^ Jump up to:ab Böhm, C. and Jacopini, G.: “Flow diagrams, Turing machines and languages with only two formation rules”, CACM 9(5), 1966. (Note: This is the most-cited paper on the structured program theorem.)

Ofer Abarbanel – Executive Profile

Ofer Abarbanel online library

Ofer Abarbanel online library

Ofer Abarbanel online library

Ofer Abarbanel online library