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Fix: simplecpp ## fails to expand function-like macro when '(' is not adjacent #655

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Fix: simplecpp ## fails to expand function-like macro when '(' is not adjacent #655

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59 changes: 53 additions & 6 deletions simplecpp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2381,16 +2381,63 @@ namespace simplecpp {
output.deleteToken(A);
TokenList tokens(files);
tokens.push_back(new Token(strAB, tok->location));
// for function like macros, push the (...)
if (tokensB.empty() && sameline(B,B->next) && B->next->op=='(') {
const MacroMap::const_iterator it = macros.find(strAB);
if (it != macros.end() && expandedmacros.find(strAB) == expandedmacros.end() && it->second.functionLike()) {
const Token * const tok2 = appendTokens(tokens, loc, B->next, macros, expandedmacros, parametertokens);
// If strAB names a function-like macro, locate and append its argument list '(...)'
// from the remaining replacement tokens, then expand the whole call.
// 'forwardScan' is true when the argument list was consumed via the forward scan
// path below (not adjacent), so that expandToken() is called instead of
// the normal takeTokens() path even when expandResult is false.
bool forwardScan = false;
const MacroMap::const_iterator it = macros.find(strAB);
const bool isFunctionLikeMacro = (it != macros.end() && expandedmacros.find(strAB) == expandedmacros.end() && it->second.functionLike());
if (tokensB.empty() && isFunctionLikeMacro) {
// Fast path: '(' is the very next token after B on the same line.
const Token *lpar = (sameline(B, B->next) && B->next->op == '(') ? B->next : nullptr;
if (!lpar && !expandResult) {
// Forward-scan path: '(' is not immediately adjacent to B.
// This handles PAR-style indirection patterns such as:
// #define PAR(a, ...) a __VA_ARGS__
// #define DISPATCH(kind, ...) PAR(PREFIX_ ## kind, (__VA_ARGS__))
// where the '(' for PREFIX_kind belongs to the __VA_ARGS__ parameter
// and is separated from B by a comma in the replacement text.
// Only active in the appendTokens context (expandResult==false) to
// avoid unintended side-effects inside the main expansion loop.
const Token *scan = nextTok;
while (scan && sameline(B, scan)) {
if (scan->op == '(') {
// Found a literal '(' after skipping separators.
lpar = scan;
forwardScan = true;
break;
}
if (scan->op == ',') {
// Argument separator — skip and keep scanning.
scan = scan->next;
continue;
}
if (scan->name) {
// Named token: expand it and check whether it starts with '(...)'
// (covers the case where __VA_ARGS__ expands to a parenthesised list).
TokenList expanded(files);
if (expandArg(expanded, scan, loc, macros, expandedmacros, parametertokens) &&
expanded.cfront() && expanded.cfront()->op == '(') {
for (Token *t = expanded.front(); t; t = t->next)
t->location = loc;
tokens.takeTokens(expanded);
nextTok = scan->next;
forwardScan = true;
}
break; // stop at any name token, whether consumed or not
}
break; // any other operator — stop scan
}
}
if (lpar) {
const Token * const tok2 = appendTokens(tokens, loc, lpar, macros, expandedmacros, parametertokens);
if (tok2)
nextTok = tok2->next;
}
}
if (expandResult)
if (expandResult || forwardScan)
expandToken(output, loc, tokens.cfront(), macros, expandedmacros, parametertokens);
else
output.takeTokens(tokens);
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