It’s not a token separator in the "#define foo(x)" example. You never get a "foo(" token, regardless of whitespace, but whitespace decides whether it’s a functi

It’s not a token separator in the "#define foo(x)" example. You never get a "foo(" token, regardless of whitespace, but whitespace decides whether it’s a function macro definition or a constant definition. The standard needed to invent a new token called lparen, which is a left round bracket that is not preceded by whitespace, to make it make any sense.