Fix an issue with unescaped values + Add tests

compiler/lexer.cpp

@@ -33,6 +33,8 @@
 #include <string>
 #include <unordered_set>
 #include <utility>
+#include <iomanip>
+#include <sstream>
 
 #if defined __linux__ || defined __FreeBSD__ || defined __OpenBSD__ || defined DARWIN
 #    include <unistd.h>
@@ -2572,15 +2574,11 @@ std::string Lexer::PerformMacroSubstitution(MacroEntry* macro,
             continue;
         }
         if (stringize) {
-            out += '"';
-
             auto arg_macro = FindMacro(cc_.atom(iter->second));
             if (arg_macro != nullptr && !arg_macro->args)
-                out += arg_macro->substitute->str();
+                out += QuoteString(arg_macro->substitute->str());
             else
-                out += iter->second;
-
-            out += '"';
+                out += QuoteString(iter->second);
         }
         else
             out += iter->second;
@@ -2663,4 +2661,10 @@ void Lexer::DiscardCachedTokens() {
     injected_token_stream_.clear();
 }
 
+std::string QuoteString(const std::string& string) {
+	std::stringstream ss;
+	ss << std::quoted(string);
+	return ss.str();
+}
+
 } // namespace sp

compiler/lexer.h

@@ -533,5 +533,6 @@ class Lexer
 };
 
 std::string StringizePath(const std::filesystem::path& in_path);
+std::string QuoteString(const std::string& string);
 
 } // namespace sp

tests/macros/stringification.out

@@ -0,0 +1,6 @@
+ab
+"ab"
+C3
+C3()
+C4(15)
+UNDEFINED

tests/macros/stringification.sp

@@ -0,0 +1,27 @@
+#include <shell>
+
+#define TO_STR(%0)  #%0
+
+#define C1          ab
+#define C2          "ab"
+#define C3()        cd
+#define C4(%0)      %0
+
+public main() {
+    print(TO_STR(C1));
+    print("\n");
+
+    print(TO_STR(C2));
+    print("\n");
+
+    print(TO_STR(C3));
+    print("\n");
+
+    print(TO_STR(C3()));
+    print("\n");
+
+    print(TO_STR(C4(15)));
+    print("\n");
+
+    print(TO_STR(UNDEFINED));
+}