Sometimes when I am programming, I find that some particular control structure would be very useful to me, but is not directly available in my programming language. I think my most common desire is something like a "split while" (I have no idea what to actually call this):

{ foo(); } split_while( condition ) { bar(); }

The semantics of this code would be that foo() is always run, and then the condition is checked. If true, then bar() is run and we go back to the first block (thus running foo() again, etc). Thanks to a comment by reddit user zxqdms, I have learned that Donald E. Knuth writes about this structure in his paper "Structured programming with go to statements" (see page 279).

What alternative control structures do you think are a useful way of organizing computation?

My goal here is to give myself and others new ways of thinking about structuring code, in order to improve chunking and reasoning.