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Fix #688: Support #elifdef and #elifndef #691

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Fix #688: Support #elifdef and #elifndef #691

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47ead4b
add tests
ludviggunne Jul 23, 2026
65c5ed6
fix
ludviggunne Jul 23, 2026
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18 changes: 12 additions & 6 deletions simplecpp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -96,6 +96,8 @@ static const simplecpp::TokenString IFNDEF("ifndef");
static const simplecpp::TokenString DEFINED("defined");
static const simplecpp::TokenString ELSE("else");
static const simplecpp::TokenString ELIF("elif");
static const simplecpp::TokenString ELIFDEF("elifdef");
static const simplecpp::TokenString ELIFNDEF("elifndef");
static const simplecpp::TokenString ENDIF("endif");

static const simplecpp::TokenString PRAGMA("pragma");
Expand Down Expand Up @@ -3580,7 +3582,9 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
continue;
}

if (ifstates.size() <= 1U && (rawtok->str() == ELIF || rawtok->str() == ELSE || rawtok->str() == ENDIF)) {
if (ifstates.size() <= 1U && (rawtok->str() == ELIF || rawtok->str() == ELIFDEF ||
rawtok->str() == ELIFNDEF || rawtok->str() == ELSE ||
rawtok->str() == ENDIF)) {
if (outputList) {
simplecpp::Output err{
Output::SYNTAX_ERROR,
Expand Down Expand Up @@ -3721,7 +3725,8 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
rawtok = filedata->tokens.cfront();
continue;
}
} else if (rawtok->str() == IF || rawtok->str() == IFDEF || rawtok->str() == IFNDEF || rawtok->str() == ELIF) {
} else if (rawtok->str() == IF || rawtok->str() == IFDEF || rawtok->str() == IFNDEF || rawtok->str() == ELIF ||
((getCStd(dui.std) >= C23 || getCppStd(dui.std) >= CPP23) && (rawtok->str() == ELIFDEF || rawtok->str() == ELIFNDEF))) {

@danmar danmar Jul 23, 2026

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I feel that we don't need to check the standard. If we see #elifdef we can use the same handling used in C23/C++23.. Let's check the standard if some different behaviors are wanted.

if (!sameline(rawtok,rawtok->next)) {
if (outputList) {
simplecpp::Output out{
Expand All @@ -3736,10 +3741,11 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
}

bool conditionIsTrue;
if (ifstates.top() == AlwaysFalse || (ifstates.top() == ElseIsTrue && rawtok->str() != ELIF)) {
if (ifstates.top() == AlwaysFalse || (ifstates.top() == ElseIsTrue && rawtok->str() != ELIF &&
rawtok->str() != ELIFDEF && rawtok->str() != ELIFNDEF)) {
conditionIsTrue = false;
}
else if (rawtok->str() == IFDEF) {
else if (rawtok->str() == IFDEF || rawtok->str() == ELIFDEF) {
const std::string &name = rawtok->next->str();
conditionIsTrue = (macros.find(name) != macros.end() || (hasInclude && name == HAS_INCLUDE));
maybeUsedMacros[name].emplace_back(rawtok->next->location);
Expand All @@ -3748,7 +3754,7 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
const long long result = conditionIsTrue ? 1 : 0;
ifCond->emplace_back(rawtok->location, E, result);
}
} else if (rawtok->str() == IFNDEF) {
} else if (rawtok->str() == IFNDEF || rawtok->str() == ELIFNDEF) {
const std::string &name = rawtok->next->str();
conditionIsTrue = (macros.find(name) == macros.end() && !(hasInclude && name == HAS_INCLUDE));
maybeUsedMacros[name].emplace_back(rawtok->next->location);
Expand Down Expand Up @@ -3879,7 +3885,7 @@ void simplecpp::preprocess(simplecpp::TokenList &output, const simplecpp::TokenL
}
}

if (rawtok->str() != ELIF) {
if (rawtok->str() != ELIF && rawtok->str() != ELIFDEF && rawtok->str() != ELIFNDEF) {
// push a new ifstate..
if (ifstates.top() != True)
ifstates.push(AlwaysFalse);
Expand Down
78 changes: 78 additions & 0 deletions test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2370,6 +2370,82 @@ static void elif()
ASSERT_EQUALS("\n\n\n\n\n3", preprocess(code3));
}

static void elifdef()
{
simplecpp::DUI dui;
dui.std = "c++23";

{
const char code[] = "#if 1\n"
"1\n"
"#elifdef X\n"
"2\n"
"#else\n"
"3\n"
"#endif";
ASSERT_EQUALS("\n1", preprocess(code, dui));
}
{
const char code[] = "#define X\n"
"#if 0\n"
"1\n"
"#elifdef X\n"
"2\n"
"#else\n"
"3\n"
"#endif";
ASSERT_EQUALS("\n\n\n\n2", preprocess(code, dui));
}
{
const char code[] = "#if 0\n"
"1\n"
"#elifdef X\n"
"2\n"
"#else\n"
"3\n"
"#endif";
ASSERT_EQUALS("\n\n\n\n\n3", preprocess(code, dui));
}
}

static void elifndef()
{
simplecpp::DUI dui;
dui.std = "c++23";

{
const char code[] = "#if 1\n"
"1\n"
"#elifndef X\n"
"2\n"
"#else\n"
"3\n"
"#endif";
ASSERT_EQUALS("\n1", preprocess(code, dui));
}
{
const char code[] = "#if 0\n"
"1\n"
"#elifndef X\n"
"2\n"
"#else\n"
"3\n"
"#endif";
ASSERT_EQUALS("\n\n\n2", preprocess(code, dui));
}
{
const char code[] = "#define X\n"
"#if 0\n"
"1\n"
"#elifndef X\n"
"2\n"
"#else\n"
"3\n"
"#endif";
ASSERT_EQUALS("\n\n\n\n\n\n3", preprocess(code, dui));
}
}

static void ifif()
{
// source code from LLVM
Expand Down Expand Up @@ -4329,6 +4405,8 @@ static void runTests(int argc, char **argv, Input input)
TEST_CASE(ifLogical);
TEST_CASE(ifSizeof);
TEST_CASE(elif);
TEST_CASE(elifdef);
TEST_CASE(elifndef);
TEST_CASE(ifif);
TEST_CASE(ifoverflow);
TEST_CASE(ifdiv0);
Expand Down
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