[kazinator]

Lisp is unambiguous, whereas:

   x = a ? b : c;

Oops; that assigns x = a, and tests it. Not if that = is that of an initializer, though:

   int x = a ? : b : c;

so now we have an expression that changes meaning if we have to split the initialization off into an assignment.

You're often better off if you put it behind a macro:

  #define IF(X, Y, Z) ((X) ? (Y) : (Z))

In C coding, a lot of ternary action happens behind the curtain of preprocessing, where expression is almost fully parenthesized.

[pcvarmint]

C non-sequitor. Assignment is always lower in precedence than conditional expressions.

CPP macros is red herring.