hoc, an acronym for High Order Calculator, is an interpreted

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

that was used in the 1984 book The Unix Programming Environment to demonstrate how to build interpreters using

Yacc Yacc (Yet Another Compiler-Compiler) is a computer program for the Unix operating system developed by Stephen C. Johnson. It is a lookahead left-to-right rightmost derivation (LALR) parser generator, generating a LALR parser (the part of a co ...

. hoc was developed by

Brian Kernighan Brian Wilson Kernighan (; born January 30, 1942) is a Canadian computer scientist. He worked at Bell Labs and contributed to the development of Unix alongside Unix creators Ken Thompson and Dennis Ritchie. Kernighan's name became widely known ...

and

Rob Pike Robert Pike (born 1956) is a Canadian programmer and author. He is best known for his work on the Go programming language while working at Google and the Plan 9 operating system while working at Bell Labs, where he was a member of the Unix t ...

as a glorified interactive calculator. Its basic functionality is to evaluate floating-point numerical expressions, e.g., . Then, variables were added, conditionals, loops, user-defined functions, simple IO, and more, using a syntax resembling C. An improved hoc interpreter was included in Eighth Edition

Research Unix Research Unix refers to the early versions of the Unix operating system for DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC). The term ''Research Unix'' first app ...

in 1985, but it has not been generally adopted by commercial

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

systems or by

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

distributions. Instead, the earlier calculator languages dc and bc have become widespread on those systems. hoc survived and continued to evolve as part of the Plan 9 operating system. Several improved versions of hoc were released as

free software Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed open-source license, under terms that allow users to run the software for any purpose as well as to study, change, distribut ...

by Bell Labs and other individuals (see list below). hoc is used, alongside python, as a scripting language for the Neuron simulator.

Examples

The following is a simple example of an interactive calculator session in hoc; text represents hoc's output: 1+2*3 7 angle=PI/3 r=sin(angle) r 0.866025 r*2 1.73205 And a simple example of functions and flow control: func atan2() atan2(2,3) 0.982794 atan2(0,0) atan2 domain error 0.0

References

External links

hoc implementations and versions

* AT&T versions: *
The original code from the Unix Programming Environment book
including hoc. *
Source code of hoc
from Bell Labs, released as

. This is the Research Unix version, slightly improved over the one in the book. *
Plan9 version of hoc
released under the

MIT License The MIT License is a permissive software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts very few restrictions on reuse and therefore has high license compatibility. Unl ...

. This version is slightly different from the Research Unix version, with the most notable difference being that numbered function arguments ($1, $2, etc., as in the Unix shell) were replaced by named arguments (as in C). See also Plan 9'
hoc manual
* Other versions: *
an extended version of hoc
by Nelson H. F. Beebe. *
an extended version of hoc
by Nadav Y. Har'El. *
an extended version of hoc
by Jack Dennon. *

by Michael Hines, John W. Moore, and Ted Carnevale. {{Plan 9 commands Software calculators Free mathematics software Numerical programming languages Unix programming tools Plan 9 commands