V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

PLI
       Programming Language One (DEC), "PL/I"


The Free On-line Dictionary of Computing (30 December 2018):

PL/I

    Programming Language One.

   An attempt to combine the best features of Fortran, COBOL
   and ALGOL 60.  Developed by George Radin of IBM in 1964.
   Originally named NPL and Fortran VI.  The result is large but
   elegant.  PL/I was one of the first languages to have a formal
   semantic definition, using the Vienna Definition Language.
   EPL, a dialect of PL/I, was used to write almost all of the
   Multics operating system.  PL/I is still widely used
   internally at IBM.  The PL/I standard is ANS X3.53-1976.

   PL/I has no reserved words.  Types are fixed, float,
   complex, character strings with maximum length, bit strings,
   and label variables.  Arrays have lower bounds and may be
   dynamic.  It also has summation, multi-level structures,
   structure assignment, untyped pointers, side effects and
   aliasing.  Control flow constructs include goto; do-end
   groups; do-to-by-while-end loops; external procedures;
   internal nested procedures and blocks; generic procedures
   and exception handling.  Procedures may be declared
   recursive.  Many implementations support concurrency
   ('call task' and 'wait(event)' are equivalent to fork/join)
   and compile-time statements.

   LPI is a PL/I interpreter.

   ["A Structural View of PL/I", D. Beech, Computing Surveys, 2,1
   33-64 (1970)].

   (1994-10-25)