[core] Introduce _R_QUOTEVAL_ macro to quote preprecessor macro values

This introduces a new helper macro that is used in several places in
ROOT.

Author: guitargeek

core/base/src/TROOT.cxx

@@ -1993,9 +1993,7 @@ void TROOT::InitSystem()
       if (gSystem->Init())
          fprintf(stderr, "Fatal in <TROOT::InitSystem>: can't init operating system layer\n");
 
-#define TO_LITERAL(string) _QUOTE_(string)
-
-      TString rootincludedir = TO_LITERAL(CMAKE_INSTALL_INCLUDEDIR);
+      TString rootincludedir = _R_QUOTEVAL_(CMAKE_INSTALL_INCLUDEDIR);
       gSystem->PrependPathName(GetRootSys(), rootincludedir);
       gSystem->SetIncludePath(("-I" + rootincludedir).Data());
 
@@ -3052,7 +3050,7 @@ const TString &TROOT::GetLibDir()
          continue;
 
       fs::path p(path);
-      if (p.filename() == TO_LITERAL(LIB_CORE_NAME)) {
+      if (p.filename() == _R_QUOTEVAL_(LIB_CORE_NAME)) {
          rootlibdir = p.parent_path().c_str();
          break;
       }
@@ -3072,7 +3070,7 @@ const TString &TROOT::GetLibDir()
          return 0;
 
       fs::path p = info->dlpi_name;
-      if (p.filename() == TO_LITERAL(LIB_CORE_NAME)) {
+      if (p.filename() == _R_QUOTEVAL_(LIB_CORE_NAME)) {
          libdir = p.parent_path().c_str();
          return 1; // stop iteration
       }

core/foundation/inc/ROOT/RConfig.hxx

@@ -447,6 +447,8 @@
 
 #endif
 
+#define _R_QUOTEVAL_(string) _QUOTE_(string)
+
 /* produce an identifier that is almost unique inside a file */
 #   define _R__JOIN_(X,Y) _NAME2_(X,Y)
 #   define _R__JOIN3_(F,X,Y) _NAME3_(F,X,Y)

roofit/batchcompute/src/RooBatchCompute.cxx

@@ -92,12 +92,7 @@ class RooBatchComputeClass : public RooBatchComputeInterface {
    std::string architectureName() const override
    {
       // transform to lower case to match the original architecture name passed to the compiler
-#ifdef _QUOTEVAL_ // to quote the value of the preprocessor macro instead of the name
-#error "It's unexpected that _QUOTEVAL_ is defined at this point!"
-#endif
-#define _QUOTEVAL_(x) _QUOTE_(x)
-      std::string out = _QUOTEVAL_(RF_ARCH);
-#undef _QUOTEVAL_
+      std::string out = _R_QUOTEVAL_(RF_ARCH);
       std::transform(out.begin(), out.end(), out.begin(), [](unsigned char c) { return std::tolower(c); });
       return out;
    };

tree/tree/test/TTreeRegressions.cxx

@@ -238,12 +238,11 @@ TEST(TTreeRegressions, EmptyLeafObject)
 #define MYCLASS struct MyClass { std::vector<MySubClass> sub; MySubClass *Get(int id) { for (size_t i = 0; i < sub.size(); ++i) if (sub[i].id == id) return &sub[i]; return nullptr; } };
 MYSUBCLASS
 MYCLASS
-#define TO_LITERAL(string) _QUOTE_(string)
 
 TEST(TTreeRegressions, TTreeFormulaMemberIndex)
 {
-   gInterpreter->Declare(TO_LITERAL(MYSUBCLASS));
-   gInterpreter->Declare(TO_LITERAL(MYCLASS));
+   gInterpreter->Declare(_R_QUOTEVAL_(MYSUBCLASS));
+   gInterpreter->Declare(_R_QUOTEVAL_(MYCLASS));
 
    TTree tree("tree", "tree");
    MyClass mc;

tree/treeplayer/test/regressions.cxx

@@ -216,10 +216,9 @@ TEST(TTreeFormulaRegressions, ConstantAlias)
 // ROOT-8577 (JIRA)
 #define MYSTRUCT struct MyS { int x; };
 MYSTRUCT
-#define TO_LITERAL(string) _QUOTE_(string)
 TEST(TTreeFormulaRegressions, WrongName)
 {
-   gInterpreter->Declare(TO_LITERAL(MYSTRUCT));
+   gInterpreter->Declare(_R_QUOTEVAL_(MYSTRUCT));
    MyS s;
    TLorentzVector v(1, 2, 3, 4);
    TTree t("t", "t");