Header cleanup with C++11 as a baseline (#1364)

* First step of simplifying compiler checks

There is more that can be done but each removal of a #DEFINE needs to check
exactly where it is used.  The bottom part of compiler.h still spans a grid
over C++0x/TR1 to see if unordered map and set are a given (as in C++11 or
later) which together with other calls of 'C++11 it is now' can simplify but
we need to carefully walk this through the rest of the code and not just
delete here as we'd keep unnecessary #define 'orphans' around.

* Do not rely on __has_feature() for g++

Given that we test for C++11 we can assume variadic templates and just
use the #define. Can likely be generalized to icc and clang too.

* Expand macos matrix to macos-13, simplify via r-ci with bootstrap

* No longer provide fallback for unordered_{set,map} which are given

Removes one if/else use in table.h for map, none for set

* Further cleanup

* Reduced compiler.h to about a page of mostly defines and includes

* Additional simplification, and typo fix

* Remove HAS_STATIC_ASSERT define and simplify at its sole use

* Reflect code review comments

* Following rebase roll micro release and date, update ChangeLog

* Remove remaining stray HAS_CXX0X_INITIALIZER_LIST

Author: eddelbuettel

.github/workflows/macos.yaml

@@ -14,7 +14,8 @@ jobs:
     strategy:
       matrix:
         include:
-          - {os: macOS-latest}
+          - {os: macos-latest}
+          - {os: macos-13}
           #- {os: ubuntu-latest}
 
     runs-on: ${{ matrix.os }}
@@ -24,10 +25,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup
-        uses: eddelbuettel/github-actions/r-ci-setup@master
-
-      - name: Bootstrap
-        run: ./run.sh bootstrap
+        uses: eddelbuettel/github-actions/r-ci@master
 
       - name: Dependencies
         run: ./run.sh install_deps

ChangeLog

@@ -1,3 +1,19 @@
+2025-03-15  Dirk Eddelbuettel  <edd@debian.org>
+
+	* DESCRIPTION (Version, Date): Roll micro version and date
+	* inst/include/Rcpp/config.h: Idem
+
+	* inst/include/Rcpp/platform/compiler.h: Simplified and shortened
+	establishing C++11 as baseline; further PRs to complete this
+	* inst/include/Rcpp/String.h: Unconditionally use std::hash with C++11
+	* inst/include/Rcpp/wrap.h: Unconditionally use static_assert
+	* inst/include/Rcpp/sugar/functions/sapply.h: Use std::result_of
+	(with C++11 or C++14) or std::invoke_result (C++17 or later)
+	* inst/include/Rcpp/sugar/functions/table.h: Use std::map
+	* inst/include/Rcpp/sugar/sets.h: Use std::unordered_{set,map}
+	* man/evalCpp.Rd: Update example
+	* src/api.cpp: Simplify rcpp_capabilities assignment
+
 2025-03-13  Dirk Eddelbuettel  <edd@debian.org>
 
 	* DESCRIPTION (Version, Date): Roll micro version and date

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: Rcpp
 Title: Seamless R and C++ Integration
-Version: 1.0.14.6
-Date: 2025-03-13
+Version: 1.0.14.7
+Date: 2025-03-15
 Authors@R: c(person("Dirk", "Eddelbuettel", role = c("aut", "cre"), email = "edd@debian.org",
                     comment = c(ORCID = "0000-0001-6419-907X")),
              person("Romain", "Francois", role = "aut",

inst/include/Rcpp/String.h

@@ -734,24 +734,14 @@ namespace Rcpp {
 
 } // Rcpp
 
-/** hash can be in std or std::tr1 */
-#if defined(RCPP_USING_CXX11) || defined(HAS_TR1)
-namespace std
-{
-#ifndef RCPP_USING_CXX11
-namespace tr1 {
-#endif
+/** hash via std */
+namespace std {
     template <>
-    struct hash<Rcpp::String>
-    {
+    struct hash<Rcpp::String>  {
         size_t operator()(const Rcpp::String & s) const{
             return hash<string>()(s.get_cstring());
         }
     };
-#ifndef RCPP_USING_CXX11
-}
-#endif
 }
-#endif
 
 #endif

inst/include/Rcpp/config.h

@@ -30,7 +30,7 @@
 #define RCPP_VERSION_STRING     "1.0.14"
 
 // the current source snapshot (using four components, if a fifth is used in DESCRIPTION we ignore it)
-#define RCPP_DEV_VERSION        RcppDevVersion(1,0,14,6)
-#define RCPP_DEV_VERSION_STRING "1.0.14.6"
+#define RCPP_DEV_VERSION        RcppDevVersion(1,0,14,7)
+#define RCPP_DEV_VERSION_STRING "1.0.14.7"
 
 #endif

inst/include/Rcpp/internal/wrap.h

@@ -522,18 +522,12 @@ namespace Rcpp {
          * quite a cryptic message
          */
 	template <typename T>
-        inline SEXP wrap_dispatch_unknown_iterable(const T& object, ::Rcpp::traits::false_type) {
-            RCPP_DEBUG_1("wrap_dispatch_unknown_iterable<%s>(., false )", DEMANGLE(T))
-	    // here we know that T is not convertible to SEXP
-	    #ifdef HAS_STATIC_ASSERT
-                static_assert(!sizeof(T), "cannot convert type to SEXP");
-            #else
-                // leave the cryptic message
-                SEXP x = object;
-                return x;
-            #endif
-            return R_NilValue; // -Wall
-        }
+    inline SEXP wrap_dispatch_unknown_iterable(const T& object, ::Rcpp::traits::false_type) {
+        RCPP_DEBUG_1("wrap_dispatch_unknown_iterable<%s>(., false )", DEMANGLE(T))
+        // here we know that T is not convertible to SEXP
+        static_assert(!sizeof(T), "cannot convert type to SEXP");
+        return R_NilValue; // -Wall
+    }
 
 	template <typename T>
         inline SEXP wrap_dispatch_unknown_iterable__logical(const T& object, ::Rcpp::traits::true_type) {
@@ -936,7 +930,7 @@ namespace Rcpp {
          if (v != NULL)
              return Rf_mkString(v);
          else
-             return R_NilValue; 			// #nocov 
+             return R_NilValue; 			// #nocov
      }
 
      /**

inst/include/Rcpp/platform/compiler.h

@@ -1,8 +1,6 @@
-// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-
-//
 // compiler.h: Rcpp R/C++ interface class library -- check compiler
 //
-// Copyright (C) 2012 - 2013  Dirk Eddelbuettel, Romain Francois, and Kevin Ushey
+// Copyright (C) 2012 - 2025  Dirk Eddelbuettel, Romain Francois, and Kevin Ushey
 //
 // This file is part of Rcpp.
 //
@@ -24,173 +22,30 @@
 
 // NB: A vast list valid identifiers is at these wiki pages:
 //     http://sourceforge.net/p/predef/wiki/Home/
-
-#undef GOOD_COMPILER_FOR_RCPP
-#ifdef __GNUC__
-#define GOOD_COMPILER_FOR_RCPP
-#endif
-#ifdef __SUNPRO_CC
-#define GOOD_COMPILER_FOR_RCPP
-#endif
-#ifdef __clang__
-#define GOOD_COMPILER_FOR_RCPP
-#endif
-#ifdef __INTEL_COMPILER
-#define GOOD_COMPILER_FOR_RCPP
-#endif
-
-#ifndef GOOD_COMPILER_FOR_RCPP
-# error "This compiler is not supported"
-#endif
-
-#ifdef __GNUC__
-    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-    // g++ 4.5 does not seem to like some of the fast indexing
-    #if GCC_VERSION >= 40500
-        #define IS_GCC_450_OR_LATER
-    #endif
-    // g++ 4.6 switches from exception_defines.h to bits/exception_defines.h
-    #if GCC_VERSION < 40600
-        #define IS_EARLIER_THAN_GCC_460
-    #endif
-    #if GCC_VERSION >= 40600
-        #define IS_GCC_460_OR_LATER
-    #endif
-#endif
-
-// Check for the presence of C++0x (or later) support
-#if defined(__GXX_EXPERIMENTAL_CXX0X__) || (__cplusplus >= 201103L)
-  #define RCPP_USING_CXX0X_OR_LATER
+#if !defined(__GNUC__) && !defined(__SUNPRO_CC) && !defined(__clang__) && !defined(__INTEL_COMPILER)
+#error "This compiler is not supported"
 #endif
 
-// Check C++0x/11 features
-#if defined(__INTEL_COMPILER)
-    #if __cplusplus >= 201103L
-        #define RCPP_USING_CXX11
-        #if __INTEL_COMPILER >= 1210
-            #define HAS_VARIADIC_TEMPLATES
-        #endif
-        #if __INTEL_COMPILER >= 1100
-            #define HAS_STATIC_ASSERT
-        #endif
-    #endif
-#elif defined(__clang__)
-    #if __cplusplus >= 201103L
-        #define RCPP_USING_CXX11
-        #if __has_feature(cxx_variadic_templates)
-            #define HAS_VARIADIC_TEMPLATES
-        #endif
-        #if __has_feature(cxx_static_assert)
-            #define HAS_STATIC_ASSERT
-        #endif
-    #endif
-#elif defined(__GNUC__)
-    #ifdef __GXX_EXPERIMENTAL_CXX0X__
-        #if GCC_VERSION >= 40300
-            #define HAS_VARIADIC_TEMPLATES
-            #define HAS_STATIC_ASSERT
-        #endif
-    #endif
-	#if GCC_VERSION >= 40800 && __cplusplus >= 201103L
-		#define RCPP_USING_CXX11
-	#endif
+// Simpler test and minimal standard: C++11 or else we die
+#if __cplusplus < 201103L
+#error "The C++ compilation standard is too old: use C++11 or newer."
 #endif
 
-// Check C++0x headers
+// C++11 features -- that used to be carefully tested for or worked around via CXX0X / TR1
+// These defines are all planned to get removed just how a number have already been removed. One at a time...
+#define RCPP_USING_CXX11
+#define HAS_VARIADIC_TEMPLATES
 #include <cmath>
-#if defined(__INTEL_COMPILER) || (defined(__GNUC__) && !defined(__clang__))
-    #if defined(__GLIBCXX__) && defined(__GXX_EXPERIMENTAL_CXX0X__)
-        #if GCC_VERSION >= 40400
-            #define HAS_CXX0X_UNORDERED_MAP
-            #define HAS_CXX0X_UNORDERED_SET
-            #define HAS_CXX0X_INITIALIZER_LIST
-        #endif
-    #endif
-#elif defined(__clang__)
-    #if __cplusplus >= 201103L
-        #if __has_include(<unordered_map>)
-            #define HAS_CXX0X_UNORDERED_MAP
-        #endif
-        #if __has_include(<unordered_set>)
-            #define HAS_CXX0X_UNORDERED_SET
-        #endif
-        #if __has_include(<initializer_list>)
-            #define HAS_CXX0X_INITIALIZER_LIST
-        #endif
-    #endif
-#endif
-
-// Check TR1 Headers
-#if defined(__INTEL_COMPILER) || (defined(__GNUC__) && !defined(__clang__))
-    #if defined(__GLIBCXX__)
-        #if GCC_VERSION >= 40400 || ( GCC_VERSION >= 40201 && defined(__APPLE__) )
-            #define HAS_TR1_UNORDERED_MAP
-            #define HAS_TR1_UNORDERED_SET
-        #endif
-    #endif
-#elif defined(__clang__)
-    #if __cplusplus >= 201103L
-        #if __has_include(<tr1/unordered_map>)
-            #define HAS_TR1_UNORDERED_MAP
-        #endif
-        #if __has_include(<tr1/unordered_set>)
-            #define HAS_TR1_UNORDERED_SET
-        #endif
-    #endif
-#endif
-
-#if defined(HAS_TR1_UNORDERED_MAP) && defined(HAS_TR1_UNORDERED_SET)
-#define HAS_TR1
-#endif
-
-// Conditionally include headers
-#ifdef HAS_CXX0X_INITIALIZER_LIST
 #include <initializer_list>
-#endif
-
-#ifdef RCPP_USING_CXX11
-    #if defined(HAS_CXX0X_UNORDERED_MAP)
-        #include <unordered_map>
-        #define RCPP_USING_UNORDERED_MAP
-        #define RCPP_UNORDERED_MAP std::unordered_map
-    #else
-        #include <map>
-        #define RCPP_USING_MAP
-        #define RCPP_UNORDERED_MAP std::map
-    #endif
-    #if defined(HAS_CXX0X_UNORDERED_SET)
-        #include <unordered_set>
-        #define RCPP_USING_UNORDERED_SET
-        #define RCPP_UNORDERED_SET std::unordered_set
-    #else
-        #include <set>
-        #define RCPP_USING_SET
-        #define RCPP_UNORDERED_SET std::set
-    #endif
-#else
-    #if defined(HAS_TR1_UNORDERED_MAP)
-        #include <tr1/unordered_map>
-        #define RCPP_USING_TR1_UNORDERED_MAP
-        #define RCPP_UNORDERED_MAP std::tr1::unordered_map
-    #else
-        #include <map>
-        #define RCPP_USING_MAP
-        #define RCPP_UNORDERED_MAP std::map
-    #endif
-    #if defined(HAS_TR1_UNORDERED_SET)
-        #include <tr1/unordered_set>
-        #define RCPP_USING_TR1_UNORDERED_SET
-        #define RCPP_UNORDERED_SET std::tr1::unordered_set
-    #else
-        #include <set>
-        #define RCPP_USING_SET
-        #define RCPP_UNORDERED_SET std::set
-    #endif
-#endif
-
-#ifdef __GNUC__
+#include <unordered_map>
+#define RCPP_USING_UNORDERED_MAP
+#define RCPP_UNORDERED_MAP std::unordered_map
+#include <unordered_set>
+#define RCPP_USING_UNORDERED_SET
+#define RCPP_UNORDERED_SET std::unordered_set
+
+#if defined(__GNUC__)
   #define RCPP_HAS_DEMANGLING
 #endif
 
-
 #endif

inst/include/Rcpp/sugar/functions/sapply.h

@@ -21,17 +21,16 @@
 #ifndef Rcpp__sugar__sapply_h
 #define Rcpp__sugar__sapply_h
 
-#if defined(RCPP_USING_CXX0X_OR_LATER)
-	#include <type_traits> // ::std::result_of
-#endif
+// This used to be conditional on a define and test in compiler.h
+#include <type_traits> // ::std::result_of
 
 namespace Rcpp{
 namespace sugar{
 
 template <typename Function, typename SugarExpression>
 struct sapply_application_result_of
 {
-#if defined(RCPP_USING_CXX0X_OR_LATER)
+#if __cplusplus >= 201103L
     #if __cplusplus < 201703L
         // deprecated by C++17, removed by C++2020, see https://en.cppreference.com/w/cpp/types/result_of
  	    typedef typename ::std::result_of<Function(typename SugarExpression::stored_type)>::type type;
@@ -40,9 +39,10 @@ struct sapply_application_result_of
         typedef typename ::std::invoke_result<Function, typename SugarExpression::stored_type>::type type;
     #endif
 #else
+    // TODO this else branch can likely go
 	typedef typename ::Rcpp::traits::result_of<Function>::type type;
 #endif
-} ;
+};
 
 // template <typename Function, typename SugarExpression>
 // using sapply_application_result_of_t = typename sapply_application_result_of<Function, SugarExpression>::type;