from
The Free On-line Dictionary of Computing (8 July 2008)
NPL
1. New Programming Language. IBM's original (temporary) name
for PL/I, changed due to conflict with England's "National
Physical Laboratory." MPL and MPPL were considered before
settling on PL/I. Sammet 1969, p.542.
2. A {functional language} with {pattern matching} designed by
Rod Burstall and John Darlington in 1977. The language
allowed certain sets and logic constructs to appear on the
right hand side of definitions, E.g.
setofeven(X) <= <:x: x in X & even(x) :>
The NPL {interpreter} evaluates the list of {generators} from
left to right so conditions can mention any bound variables
that occur to their left. These were known as {set
comprehensions}. NPL eventually evolved into {Hope} but lost
set comprehensions which were called {list comprehensions} in
later functional languages.
[John Darlington, "Program Transformation and Synthesis:
Present Capabilities", Research Report No. 77/43, Dept. of
Computing and Control, Imperial College of Science and
Technology, London September 1977.]
3. NonProcedural Language. A {relational database} language
developed by T.D. Truitt et al in 1980 for {Apple II} and
{MS-DOS}.
["An Introduction to Nonprocedural Languages Using NPL",
T.D. Truitt et al, McGraw-Hill 1983].