, "Plan Calculus") is a computer language
developed for engineering purposes by Konrad Zuse
. It was the first high-level non-von Neumann programming language
to be designed for a computer and was designed between 1943 and 1945. Also, notes survive with scribblings about such a plan calculation dating back to 1941. Plankalkül was not published at that time owing to a combination of factors such as conditions in wartime
and postwar Germany and his efforts to commercialise the Z3
computer and its successors. By 1946 Zuse had written a book on the subject but this remained unpublished. In 1948 Zuse published a paper about the Plankalkül in the "Archiv der Mathematik" but still did not attract much feedback - for a long time to come programming a computer would only be thought of as programming with machine code. The Plankalkül was eventually more comprehensively published in 1972 and the first compiler for it was implemented in 1998. Another independent implementation followed in the year 2000 by the Free University of Berlin
The German term "Kalkül
" means formal system
– the Hilbert-style deduction system
is for example originally called "Hilbert-Kalkül
", so Plankalkül means "formal system for planning".
Plankalkül drew comparisons to APL
and relational algebra
. It includes assignment statements, subroutines
, conditional statements, iteration, floating point
arithmetic, arrays, hierarchical record structures, assertions, exception handling, and other advanced features such as goal-directed execution
The example below shows a program which computes the maximum of three variables by calling the function max :
P1 max3 (V0[:8.0],V1[:8.0],V2[:8.0]) => R0[:8.0]
max(V0[:8.0],V1[:8.0]) => Z1[:8.0]
max(Z1[:8.0],V2[:8.0]) => R0[:8.0]
P2 max (V0[:8.0],V1[:8.0]) => R0[:8.0]
V0[:8.0] => Z1[:8.0]
(Z1[:8.0] < V1[:8.0]) -> V1[:8.0] => Z1[:8.0]
Z1[:8.0] => R0[:8.0]
Plankalkül shared an idiosyncratic notation using multiple lines with Frege's Begriffsschrift of 1879 (dealing with mathematical logic).
In a lecture in 1957 Zuse mentioned his hope that the Plankalkül "after some time as a Sleeping Beauty
, will yet come to life."
Heinz Rutishauser, one of the founders of ALGOL:
- "The very first attempt to devise an algorithmic language was undertaken in 1948 by K. Zuse. His notation was quite general, but the proposal never attained the consideration it deserved."
- Zuse, Konrad (1943), "Ansätze einer Theorie des allgemeinen Rechnens unter besonderer Berücksichtigung des Aussagenkalküls und dessen Anwendung auf Relaisschaltungen", unpublished manuscript, Zuse Papers 045/018.
- Zuse, Konrad (1948/49). "Über den allgemeinen Plankalkül als Mittel zur Formulierung schematisch-kombinativer Aufgaben". Arch. Math. 1, pp. 441-449, 1948/49.
- Zuse, Konrad (1972). "Der Plankalkül". Gesellschaft für Mathematik und Datenverarbeitung. Nr. 63, BMBW - GMD - 63, 1972.
- Giloi, Wolfgang, K. (1997). "Konrad Zuse's Plankalkül: The First High-Level "non von Neumann" Programming Language". IEEE Annals of the History of Computing, vol. 19, no. 2, pp. 17-24, April-June, 1997. (abstract)