Sorry, you're completely right. I had digraphs confused with character-constant escape sequences (as defined in "6.4.4.4" in C99). I.e. that the trigraphs need

Sorry, you're completely right. I had digraphs confused with character-constant escape sequences (as defined in "6.4.4.4" in C99). I.e. that the trigraphs need to be parsed like that both because they're replacements for basic syntax like "{" and "}", but also because they need to be considered as if though the parser saw a "\" in a constant, as they next character may be e.g. "n", forming a "\n", not "\\n".