return tok
			}
		}
	}
	in.Error("recursive macro invocation")
	return 0
}

func (in *Input) Text() string {
	return in.text
}

// hash processes a # preprocessor directive. It reports whether it completes.
func (in *Input) hash() bool {
	// We have a '#'; it must be followed by a known word (define, include, etc.).
	tok := in.Stack.Next()
	if tok != scanner.Ident {