Thread

1. quietbritishjim · 1789654619 · focus · HN ↗

   This will probably seem to obvious to mention to many, but it took me a few years to realise that you could replicate the "BREAK XYZ" from languages of yesteryear:

      FOR I = 1 TO 10
          FOR J = 1 TO 10
              FOR K = 1 TO 10
                  DOSOMETHING I, J, K
                  REM Breaks out of the middle loop, continues next I iteration
                  IF SOMECONDITION(I, J, K) THEN BREAK J
              NEXT K
          NEXT J
      NEXT I
   

   in modern languages by refactoring the loop you want to break out of into a function and using return instead:

      def inner_loops(i):
          for j in range(10):
              for k in range(10):
                  do_something(i, j, k)
                  if some_condition(i, j, k):
                      return
      
      def fn():
          for i in range(10):
              inner_loops(i)

   1. dhosek · 1789655435 · focus · HN ↗

      Ugh, TIL that Python doesn’t have labeled breaks. Now I’m wondering what other languages in current use don’t have this functionality.

      1. elboru · 1789656733 · focus · HN ↗

         I was about to mention C#, but I just checked and it’s coming to C# 15 in a couple of months.
      2. jcranmer · 1789659221 · focus · HN ↗

         C added it to the C2y draft about a year ago (so not in any actual released version of C). C++ is still working on adding it to the C++ draft.

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