BCPL
<language> (Basic CPL) A British systems language developed by Richards
in 1969 and descended from CPL (Combined Programming Language). BCPL is
low-level, typeless and block-structured, and provides only one-dimensional
arrays. Case is not significant, but conventionally reserved words begin with a
capital. Flow control constructs include: If-Then, Test-Then-Else, Unless-Do,
While-Do, Until-Do, Repeat, Repeatwhile, Repeatuntil, For-to-By-Do, Loop, Break
and Switchon-Into-Case-Default-Endcase. BCPL has conditional expressions,
pointers, and manifest constants. It has both procedures: 'Let foo(bar) Be
command' and functions: 'Let foo(bar) = expression'. 'Valof $(..Resultis..$)'
causes a compound command to produce a value. Parameters are call-by-value.
Program segments communicate via the global vector where system and user
variables are stored in fixed numerical locations in a single array.
The first BCPL compiler was written in AED. BCPL was used to implement the
TRIPOS operating system, which was subsequently reincarnated as AmigaDOS.
["BCPL - The Language and its Compiler", Martin Richards & Colin Whitby-Stevens,
Cambridge U Press 1979].
See OCODE, INTCODE.
Oxford BCPL differed slightly: Test-Ifso-Ifnot, and section brackets in place of
$( $).
The original INTCODE interpreter for BCPL is available for Amiga, Unix, MS-DOS
ftp://wuarchive.wustl.edu/systems/amiga/programming/languages/BCPL/.
A BCPL compiler bootstrap kit with an INTCODE interpreter in C was written by
Ken Yap
<ken@syd.dit.csiro.au>.
(1995-03-26)
Nearby terms:
BCL « BC NELIAC « BCNU « BCPL » BCS » bd »
BDC
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