Path: utzoo!utgpu!water!watmath!clyde!rutgers!lll-lcc!ames!ucbcad!zodiac!sri-spam!sri-unix!quintus!ok
From: ok@quintus.UUCP (Richard A. O'Keefe)
Newsgroups: comp.lang.c
Subject: Re: Correction
Summary: What BCPL really means
Message-ID: <511@cresswell.quintus.UUCP>
Date: 8 Jan 88 01:46:59 GMT
References: <11075@brl-adm.ARPA> <145@snark.UUCP> <146@snark.UUCP>
Organization: Quintus Computer Systems, Mountain View, CA
Lines: 63

In article <146@snark.UUCP>, eric@snark.UUCP (Eric S. Raymond) writes:
> In <145@snark.UUCP> I wrote:
> Also, I expanded 'BCPL' to 'British Common Programming Language'. Mr. Robbins
> thinks the correct name is '*Basic* Common Programming Language' and may well
> be right -- I once knew the exact name, when I was doing the research for
> the history section in _Portable_C_And_Unix_Systems_Programming_, but may
> have misremembered it.

Let's get this right once and for all.  According to the book
	BCPL - the language and its compiler
	Martin Richards & Colin Whitby-Strevens
	Cambridge University Press 1980
	ISBN 0 521 28681 6
	Price: five pounds sterling

    "BCPL was designed by .. Richards .. in 1967.
     It underwent substantial development over the next five years,
     but since then has remained relatively stable.
     ...
     The language BCPL (Basic CPL) was originally developed as a
     compiler-writing tool and, as its name suggests, is closely
     related to CPL (Combined Programming Language) which was
     jointly developed at Cambridge and London Universities."

Much of the flavour of BCPL has been retained in C.  For example,
the first program in the book is (with one change)
	GET "LIBHDR"
	LET START() BE WRITES("Hello, World*N")
which is the exact analogue of
	#include <stdio.h>
	main()
	    {
		printf("Hello, World\n");
	    }
BCPL has end-of-line comments introduced by "//".  I wonder whether the
reintroduction of this into C++ is a coincidence?

Even the idea of having a separate "lint" program was first reported for
BCPL.

The book includes source code for the first pass of a BCPL compiler.
It used to be quite easy to get a tape with a BCPL->OCODE compiler in
source form, an OCODE->INTCODE translator, and an INTCODE interpreter.
There was also a "ed"-like editor called CHEF.

The biggest difference between BCPL and C was that BCPL was designed
before byte-addressing became popular, so Array!Subscript adds a word
offset to the array address, which meant lots of multiplication by 4.
(Array%ByteOffset was added for the /370.)

If you are interested in operating systems, there was a small operating
system called OS6 written in BCPL.  The source code and commentary are
available as
	The Text of OSPub
	Christopher Strachey & Joseph Stoy
	Technical Monographs PRG-9 (t) and PRG-9 (c)
	July 1972
	Oxford University Computing Laboratory
	Programming Research Group
	45 Banbury Road,
	Oxford, Englang.
I wonder whether there has ever been another operating system without any
'goto's?