> The nesting is irrelevant to understanding the semantics

The nesting is absolutely relevant to producing the semantics.

The following uses deceptive whitespace to suggest a nesting that is contrary to the actual nesting, interfering with understanding:

  if (foo)
    if (bar)
      xyzzy();
  else
    flop();

The ternary operator A ? B : C is the goofy invention of demented mind. In nested situations, it is mind-bendingly unreadable. It behooves us to style it in a way that reveals the abstract syntax tree structure.

In C, I would in fact recommend:

  #define if3(a, b, c) ((a) ? (c) : (c))

  return if3(a < b, -1, if3(a > b, 1, 0));

Now we can have it in one line, yet it's clear.