https://issues.dlang.org/show_bug.cgi?id=13684

          Issue ID: 13684
           Summary: std.numeric.isRectangular
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: Phobos
          Assignee: nobody@puremagic.com
          Reporter: bearophile_hugs@eml.cc

I suggest to add to Phobos a simple function of common use, "isRectangular". Given a nD (2D, 3D, etc) array it verifies that the matrix is a "rectangular" nD box, with all rows of the same length, etc.

So:

assert(isRectangular([[1, 2], [3, 4]]) == true);
assert(isRectangular([[1, 2], [3]]) == false);
assert(isRectangular([[[1, 2], [3, 4]]]) == true);
assert(isRectangular([[[1, 2], [3, 4]], []]) == false);

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