fix: suppress unused parameter warnings, add doubled single-quote escaping

- Mark unused `first` parameter in 12 Tier 2 extractors as /* first */
- Handle '' (doubled single-quote) escape in scan_single_quoted_string()
- Fix unused variable warning in AllocateAligned test
- Build now produces zero warnings with -Wall -Wextra

Author: renecannao

include/sql_parser/tokenizer.h

@@ -176,7 +176,15 @@ class Tokenizer {
     Token scan_single_quoted_string() {
         ++cursor_;  // skip opening quote
         const char* content_start = cursor_;
-        while (cursor_ < end_ && *cursor_ != '\'') {
+        while (cursor_ < end_) {
+            if (*cursor_ == '\'') {
+                // Check for doubled single-quote escape ('')
+                if (cursor_ + 1 < end_ && *(cursor_ + 1) == '\'') {
+                    cursor_ += 2;  // skip both quotes
+                    continue;
+                }
+                break;  // end of string
+            }
             if (*cursor_ == '\\') {
                 ++cursor_;  // skip escaped char
                 if (cursor_ < end_) ++cursor_;

src/sql_parser/parser.cpp

@@ -127,7 +127,7 @@ void Parser<D>::scan_to_end(ParseResult& result) {
 // ---- Tier 2 Extractors ----
 
 template <Dialect D>
-ParseResult Parser<D>::extract_insert(const Token& first) {
+ParseResult Parser<D>::extract_insert(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::INSERT;
@@ -146,7 +146,7 @@ ParseResult Parser<D>::extract_insert(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_update(const Token& first) {
+ParseResult Parser<D>::extract_update(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::UPDATE;
@@ -165,7 +165,7 @@ ParseResult Parser<D>::extract_update(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_delete(const Token& first) {
+ParseResult Parser<D>::extract_delete(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::DELETE_STMT;
@@ -191,7 +191,7 @@ ParseResult Parser<D>::extract_delete(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_replace(const Token& first) {
+ParseResult Parser<D>::extract_replace(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::REPLACE;
@@ -240,7 +240,7 @@ ParseResult Parser<D>::extract_transaction(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_use(const Token& first) {
+ParseResult Parser<D>::extract_use(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::USE;
@@ -252,7 +252,7 @@ ParseResult Parser<D>::extract_use(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_show(const Token& first) {
+ParseResult Parser<D>::extract_show(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::SHOW;
@@ -261,7 +261,7 @@ ParseResult Parser<D>::extract_show(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_prepare(const Token& first) {
+ParseResult Parser<D>::extract_prepare(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::PREPARE;
@@ -270,7 +270,7 @@ ParseResult Parser<D>::extract_prepare(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_execute(const Token& first) {
+ParseResult Parser<D>::extract_execute(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::EXECUTE;
@@ -279,7 +279,7 @@ ParseResult Parser<D>::extract_execute(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_deallocate(const Token& first) {
+ParseResult Parser<D>::extract_deallocate(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::DEALLOCATE;
@@ -353,7 +353,7 @@ ParseResult Parser<D>::extract_lock(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_load(const Token& first) {
+ParseResult Parser<D>::extract_load(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::LOAD_DATA;
@@ -362,7 +362,7 @@ ParseResult Parser<D>::extract_load(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_reset(const Token& first) {
+ParseResult Parser<D>::extract_reset(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::RESET;
@@ -371,7 +371,7 @@ ParseResult Parser<D>::extract_reset(const Token& first) {
 }
 
 template <Dialect D>
-ParseResult Parser<D>::extract_unknown(const Token& first) {
+ParseResult Parser<D>::extract_unknown(const Token& /* first */) {
     ParseResult r;
     r.status = ParseResult::OK;
     r.stmt_type = StmtType::UNKNOWN;

tests/test_arena.cpp

@@ -19,7 +19,7 @@ TEST(ArenaTest, AllocateAndReset) {
 
 TEST(ArenaTest, AllocateAligned) {
     Arena arena(4096);
-    void* p1 = arena.allocate(1);
+    (void)arena.allocate(1);  // advance cursor by 1 byte
     void* p2 = arena.allocate(8);
     EXPECT_EQ(reinterpret_cast<uintptr_t>(p2) % 8, 0u);
 }