<s>
Plankalkül	B-Language
(	O
)	O
is	O
a	B-Language
programming	I-Language
language	I-Language
designed	O
for	O
engineering	O
purposes	O
by	O
Konrad	O
Zuse	O
between	O
1942	O
and	O
1945	O
.	O
</s>
<s>
It	O
was	O
the	O
first	O
high-level	B-Language
programming	I-Language
language	I-Language
to	O
be	O
designed	O
for	O
a	O
computer	O
.	O
</s>
<s>
Kalkül	O
is	O
the	O
German	O
term	O
for	O
a	O
formal	O
system	O
—	O
as	O
in	O
Hilbert-Kalkül	O
,	O
the	O
original	O
name	O
for	O
the	O
Hilbert-style	O
deduction	O
system	O
—	O
so	O
Plankalkül	B-Language
refers	O
to	O
a	O
formal	O
system	O
for	O
planning	O
.	O
</s>
<s>
In	O
the	O
domain	O
of	O
creating	O
computing	O
machines	O
,	O
Zuse	O
was	O
self-taught	O
,	O
and	O
developed	O
them	O
without	O
knowledge	O
about	O
other	O
mechanical	O
computing	O
machines	O
that	O
existed	O
already	O
–	O
although	O
later	O
on	O
(	O
building	O
the	O
Z3	B-Device
)	O
being	O
inspired	O
by	O
Hilbert	O
's	O
and	O
Ackermann	O
's	O
book	O
on	O
elementary	O
mathematical	O
logic	O
(	O
see	O
Principles	O
of	O
Mathematical	O
Logic	O
)	O
.	O
</s>
<s>
After	O
finishing	O
the	O
Z1	B-Device
in	O
1938	O
,	O
Zuse	O
discovered	O
that	O
the	O
calculus	O
he	O
had	O
independently	O
devised	O
already	O
existed	O
and	O
was	O
known	O
as	O
propositional	O
calculus	O
.	O
</s>
<s>
In	O
May	O
1939	O
he	O
described	O
his	O
plans	O
for	O
the	O
development	O
of	O
what	O
would	O
become	O
Plankalkül	B-Language
.	O
</s>
<s>
In	O
1942	O
he	O
began	O
writing	O
a	O
chess	B-Application
program	O
in	O
Plankalkül	B-Language
.	O
</s>
<s>
In	O
1945	O
,	O
Zuse	O
described	O
Plankalkül	B-Language
in	O
an	O
unpublished	O
book	O
.	O
</s>
<s>
At	O
that	O
time	O
the	O
only	O
two	O
working	O
computers	O
in	O
the	O
world	O
were	O
ENIAC	B-Device
and	O
Harvard	B-Device
Mark	I-Device
I	I-Device
,	O
neither	O
of	O
which	O
used	O
a	O
compiler	O
,	O
and	O
ENIAC	B-Device
needed	O
to	O
be	O
reprogrammed	O
for	O
each	O
task	O
by	O
changing	O
how	O
the	O
wires	O
were	O
connected	O
.	O
</s>
<s>
Although	O
most	O
of	O
his	O
computers	O
were	O
destroyed	O
by	O
Allied	O
bombs	O
,	O
Zuse	O
was	O
able	O
to	O
rescue	O
one	O
machine	O
,	O
the	O
Z4	B-Device
,	O
and	O
move	O
it	O
to	O
the	O
Alpine	O
village	O
of	O
Hinterstein	O
(	O
part	O
of	O
Bad	O
Hindelang	O
)	O
.	O
</s>
<s>
In	O
a	O
1957	O
lecture	O
,	O
Zuse	O
expressed	O
his	O
hope	O
that	O
Plankalkül	B-Language
,	O
"	O
after	O
some	O
time	O
as	O
a	O
Sleeping	O
Beauty	O
,	O
will	O
yet	O
come	O
to	O
life.	O
"	O
</s>
<s>
He	O
expressed	O
disappointment	O
that	O
the	O
designers	O
of	O
ALGOL	B-Language
58	I-Language
never	O
acknowledged	O
the	O
influence	O
of	O
Plankalkül	B-Language
on	O
their	O
own	O
work	O
.	O
</s>
<s>
Plankalkül	B-Language
was	O
more	O
comprehensively	O
published	O
in	O
1972	O
.	O
</s>
<s>
Plankalkül	B-Language
has	O
drawn	O
comparisons	O
to	O
the	O
language	O
APL	B-Language
,	O
and	O
to	O
relational	B-Algorithm
algebra	I-Algorithm
.	O
</s>
<s>
It	O
includes	O
assignment	O
statements	O
,	O
subroutines	O
,	O
conditional	O
statements	O
,	O
iteration	O
,	O
floating-point	B-Algorithm
arithmetic	I-Algorithm
,	O
arrays	O
,	O
hierarchical	O
record	O
structures	O
,	O
assertions	O
,	O
exception	O
handling	O
,	O
and	O
other	O
advanced	O
features	O
such	O
as	O
goal-directed	O
execution	O
.	O
</s>
<s>
The	O
Plankalkül	B-Language
provides	O
a	O
data	O
structure	O
called	O
generalized	O
graph	B-Application
(	O
verallgemeinerter	O
Graph	B-Application
)	O
,	O
which	O
can	O
be	O
used	O
to	O
represent	O
geometrical	O
structures	O
.	O
</s>
<s>
Many	O
features	O
of	O
the	O
Plankalkül	B-Language
reappear	O
in	O
later	O
programming	O
languages	O
;	O
an	O
exception	O
is	O
its	O
idiosyncratic	O
two-dimensional	O
notation	O
using	O
multiple	O
lines	O
.	O
</s>
<s>
Some	O
features	O
of	O
the	O
Plankalkül	B-Language
:	O
</s>
<s>
The	O
only	O
primitive	O
data	O
type	O
in	O
the	O
Plankalkül	B-Language
is	O
a	O
single	O
bit	O
or	O
boolean	O
(	O
–	O
yes-no	O
value	O
in	O
Zuse	O
's	O
terminology	O
)	O
.	O
</s>
<s>
So	O
,	O
a	O
sequence	O
of	O
eight	O
bits	O
(	O
which	O
in	O
modern	O
computing	O
could	O
be	O
regarded	O
as	O
byte	B-Application
)	O
is	O
denoted	O
by	O
,	O
and	O
boolean	O
matrix	O
of	O
size	O
by	O
is	O
described	O
by	O
.	O
</s>
<s>
Type	O
(	O
)	O
in	O
Plankalkül	B-Language
consists	O
of	O
3	O
elements	O
:	O
structured	O
value	O
(	O
)	O
,	O
pragmatic	O
meaning	O
(	O
)	O
and	O
possible	O
restriction	O
on	O
possible	O
values	O
(	O
)	O
.	O
</s>
<s>
Zuse	O
used	O
a	O
lot	O
of	O
examples	O
from	O
chess	B-Application
theory	O
:	O
</s>
<s>
Plankalkül	B-Language
allows	O
access	O
for	O
separate	O
elements	O
of	O
variable	O
by	O
using	O
"	O
component	O
index	O
"	O
(	O
)	O
.	O
</s>
<s>
Because	O
indexes	O
of	O
variables	O
are	O
written	O
vertically	O
,	O
each	O
Plankalkül	B-Language
instruction	O
requires	O
multiple	O
rows	O
to	O
write	O
down	O
.	O
</s>
<s>
Knuth	O
and	O
Pardo	O
believe	O
that	O
Zuse	O
always	O
wrote	O
,	O
and	O
that	O
was	O
introduced	O
by	O
publishers	O
of	O
«Über	O
den	O
allgemeinen	O
Plankalkül	B-Language
als	O
Mittel	O
zur	O
Formulierung	O
schematisch-kombinativer	O
Aufgaben»	O
in	O
1948	O
.	O
</s>
<s>
In	O
the	O
ALGOL	B-Language
58	I-Language
conference	O
in	O
Zurich	O
,	O
European	O
participants	O
proposed	O
to	O
use	O
for	O
assignment	O
character	O
introduced	O
by	O
Zuse	O
,	O
but	O
the	O
American	O
delegation	O
insisted	O
on	O
:=	O
.	O
</s>
<s>
He	O
envisioned	O
what	O
he	O
called	O
a	O
Planfertigungsgerät	O
(	O
"	O
plan	O
assembly	O
device	O
"	O
)	O
,	O
which	O
would	O
automatically	O
translate	O
the	O
mathematical	O
formulation	O
of	O
a	O
program	O
into	O
machine-readable	O
punched	B-Architecture
film	I-Architecture
stock	I-Architecture
.	O
</s>
