The Free On-line Dictionary of Computing (19 January 2023):

loop-and-a-half

    A loop structure with its termination test in
   the middle.  This contrasts with the more common while loop
   which has the test at the beginning or a repeat loop which
   has it at the end.

   A generic example gets a value, tests it then processes it:

    while (true) 
      value = get();
      if (isTerminal(value)) break;
      process(value);
    

   Alternatives require either an extra get() before the loop:

    value = get();
    while (! isTerminal(value))
      process(value);
      value = get();
    }

   or an extra test for termination:

    do 
      value = get();
      done = isTerminal(value);
      if (! done) process(value);
     while (! done);

   The structure is discussed, though not named as such, in

   [Donald Knuth, "Structured programming with goto statements",
   Computing Surveys, December 1974].

   A good summary is presented in

   [Eric S. Roberts, "Loop Exits and Structured Programming:
   Reopening the Debate", ACM SIGCSE, March 1995].

   (2019-09-03)