Basic Language for Implementation of System Software

Basic Language for Implementation of System Software

(language)(BLISS, or allegedly, "System SoftwareImplementation Language, Backwards") A language designed byW.A. Wulf at CMU around 1969.

BLISS is an expression language. It is block-structured,and typeless, with exception handling facilities,coroutines, a macro system, and a highly optimising compiler. It was one of the first non-assembly languagesfor operating system implementation. It gained fame for itslack of a goto and also lacks implicit dereferencing: allsymbols stand for addresses, not values.

Another characteristic (and possible explanation for thebackward acronym) was that BLISS fairly uniformly usedbackward keywords for closing blocks, a famous example beingELUDOM to close a MODULE. An exception was BEGIN...END thoughyou could use (...) instead.

DEC introduced the NOVALUE keyword in their dialects to allowstatements to not return a value.

Versions: CMU BLISS-10 for the PDP-10; CMU BLISS-11,BLISS-16, DEC BLISS-16C, DEC BLISS-32, BLISS-36 forVAX/VMS, BLISS-36C.

["BLISS: A Language for Systems Programming", CACM14(12):780-790, Dec 1971].