What's the first (oldest) language that had the 'Unless' conditional/loop built into itself?
Where an example could be
unless (myVar) == if (!myVar) until (myVar) == while (!myVar)
Software Engineering Stack Exchange is a question and answer site for professionals, academics, and students working within the systems development life cycle. It only takes a minute to sign up.Sign up to join this community
actually I've found a copy of the 1967 BCPL language manual with the UNLESS statement in it on section 6.7
this was also the first language to demonstrate the "Hello World" program
BCPL became "B" at Bell Labs and then later "C"
the joke was that the real question was what would the next language be "P" from the BCPL or "D" from the Alphabetic order
The first language I ever saw with an UNLESS statement was Intercal, whose primary control structure was the
COME FROM ... UNLESS ... statement. Intercal wasn't designed as a serious language, but it does date from 1972, and you can program in it (why you'd want to is another matter).
I think it originated with BASIC-PLUS on Digital systems in the '70s.
The Perl documentation mentions this heritage (run
perldoc perl and look in the DESCRIPTION)