Bcpl

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 [email protected].
(1995-03-26)
basic combined programming language