<s>
hoc	B-Application
,	O
an	O
acronym	O
for	O
High	O
Order	O
Calculator	O
,	O
is	O
an	O
interpreted	B-Application
programming	I-Application
language	I-Application
that	O
was	O
used	O
in	O
the	O
1984	O
book	O
The	O
Unix	B-Application
Programming	O
Environment	O
to	O
demonstrate	O
how	O
to	O
build	O
interpreters	B-Application
using	O
Yacc	B-Application
.	O
</s>
<s>
hoc	B-Application
was	O
developed	O
by	O
Brian	O
Kernighan	O
and	O
Rob	O
Pike	O
as	O
a	O
glorified	O
interactive	O
calculator	O
.	O
</s>
<s>
Then	O
,	O
variables	O
were	O
added	O
,	O
conditionals	O
,	O
loops	O
,	O
user-defined	O
functions	O
,	O
simple	O
IO	O
,	O
and	O
more	O
,	O
using	O
a	O
syntax	O
resembling	O
C	B-Language
.	O
</s>
<s>
An	O
improved	O
hoc	B-Application
interpreter	B-Application
was	O
included	O
in	O
Eighth	O
Edition	O
Research	B-Operating_System
Unix	I-Operating_System
in	O
1985	O
,	O
but	O
it	O
has	O
not	O
been	O
generally	O
adopted	O
by	O
commercial	O
Unix	B-Application
systems	I-Application
or	O
by	O
Linux	B-Application
distributions	O
.	O
</s>
<s>
Instead	O
,	O
the	O
earlier	O
calculator	O
languages	O
dc	B-Application
and	O
bc	B-Application
have	O
become	O
widespread	O
on	O
those	O
systems	O
.	O
</s>
<s>
hoc	B-Application
survived	O
and	O
continued	O
to	O
evolve	O
as	O
part	O
of	O
the	O
Plan	B-Operating_System
9	I-Operating_System
operating	O
system	O
.	O
</s>
<s>
Several	O
improved	O
versions	O
of	O
Hoc	B-Application
were	O
released	O
as	O
free	B-Application
software	I-Application
by	O
Bell	O
Labs	O
and	O
other	O
individuals	O
(	O
see	O
list	O
below	O
)	O
.	O
</s>
<s>
hoc	B-Application
is	O
used	O
as	O
the	O
primary	O
scripting	O
language	O
for	O
the	O
Neuron	O
simulator	O
.	O
</s>
<s>
The	O
following	O
is	O
a	O
simple	O
example	O
of	O
an	O
interactive	O
calculator	O
session	O
in	O
hoc	B-Application
;	O
text	O
represents	O
hoc	B-Application
's	O
output	O
:	O
</s>
