Merge pull request #204 from RcppCore/feature/logical-vector-from-bool

Feature/logical vector from bool

Author: eddelbuettel

ChangeLog

@@ -87,6 +87,19 @@
         * inst/unitTests/testRcppClass/man/Rcpp_class_examples.Rd: Similar
         update to yesterday's update for testRcppModule
 
+2014-09-14  Kevin Ushey  <kevinushey@gmail.com>
+
+        * inst/include/Rcpp/vector/Vector.h: Alternate strategy using SFINAE
+        * inst/include/Rcpp/traits/traits.h: Idem
+        * inst/include/Rcpp/traits/enable_if.h: Idem
+
+2014-09-13  Kevin Ushey  <kevinushey@gmail.com>
+
+        * inst/include/Rcpp/vector/Vector.h: Allow logical vectors to be created
+        from bools
+        * inst/unitTests/runit.Vector.R: Idem
+        * inst/unitTests/cpp/Vector.cpp: Idem
+
 2014-09-13  Dirk Eddelbuettel  <edd@debian.org>
 
         * inst/skeleton/Rcpp_modules_examples.Rd: Added to document modules examples

inst/include/Rcpp/traits/enable_if.h

@@ -0,0 +1,18 @@
+#ifndef RCPP_TRAITS_ENABLE_IF_H
+#define RCPP_TRAITS_ENABLE_IF_H
+
+namespace Rcpp {
+namespace traits {
+
+template <bool B, typename T = void>
+struct enable_if {};
+
+template <typename T>
+struct enable_if<true, T> {
+    typedef T type;
+};
+
+}
+}
+
+#endif

inst/include/Rcpp/traits/is_bool.h

@@ -0,0 +1,24 @@
+#ifndef Rcpp__traits__is_bool__h
+#define Rcpp__traits__is_bool__h
+
+namespace Rcpp{ namespace traits {
+
+template<typename>
+struct is_bool
+    : public false_type { };
+
+template<>
+struct is_bool<bool>
+    : public true_type { };
+
+template<>
+struct is_bool<const bool>
+    : public true_type { };
+
+template<>
+struct is_bool<volatile bool>
+    : public true_type { };
+
+}}
+
+#endif

inst/include/Rcpp/traits/traits.h

@@ -37,6 +37,7 @@ struct int2type { enum { value = I }; };
 
 #include <Rcpp/traits/integral_constant.h>
 #include <Rcpp/traits/same_type.h>
+#include <Rcpp/traits/enable_if.h>
 #include <Rcpp/traits/is_wide_string.h>
 #include <Rcpp/traits/char_type.h>
 #include <Rcpp/traits/named_object.h>
@@ -59,6 +60,7 @@ struct int2type { enum { value = I }; };
 #include <Rcpp/traits/is_finite.h>
 #include <Rcpp/traits/is_infinite.h>
 #include <Rcpp/traits/is_nan.h>
+#include <Rcpp/traits/is_bool.h>
 #include <Rcpp/traits/if_.h>
 #include <Rcpp/traits/get_na.h>
 #include <Rcpp/traits/is_trivial.h>

inst/include/Rcpp/vector/Vector.h

@@ -89,13 +89,13 @@ class Vector :
         fill( u ) ;
     }
 
-    // constructor for CharacterVector() 
+    // constructor for CharacterVector()
     Vector( const std::string& st ){
         RCPP_DEBUG_2( "Vector<%d>( const std::string& = %s )", RTYPE, st.c_str() )
         Storage::set__( internal::vector_from_string<RTYPE>(st) ) ;
     }
 
-    // constructor for CharacterVector() 
+    // constructor for CharacterVector()
     Vector( const char* st ) {
         RCPP_DEBUG_2( "Vector<%d>( const char* = %s )", RTYPE, st )
         Storage::set__(internal::vector_from_string<RTYPE>(st) ) ;
@@ -119,6 +119,16 @@ class Vector :
         }
     }
 
+    // Enable construction from bool for LogicalVectors
+    // SFINAE only work for template. Add template class T and then restict T to
+    // bool.
+    template <typename T>
+    Vector(T value,
+           typename Rcpp::traits::enable_if<traits::is_bool<T>::value && RTYPE == LGLSXP, void>::type* = 0) {
+        Storage::set__(Rf_allocVector(RTYPE, 1));
+        fill(value);
+    }
+
     template <typename U>
     Vector( const Dimension& dims, const U& u) {
         RCPP_DEBUG_2( "Vector<%d>( const Dimension& (%d), const U& )", RTYPE, dims.size() )

inst/unitTests/cpp/Vector.cpp

@@ -750,3 +750,14 @@ List list_sexp_assign(SEXP x) {
     L = x;
     return L;
 }
+
+// [[Rcpp::export]]
+bool logical_vector_from_bool() {
+    return true;
+}
+
+// [[Rcpp::export]]
+LogicalVector logical_vector_from_bool_assign() {
+    LogicalVector result = true;
+    return result;
+}

inst/unitTests/runit.Vector.R

@@ -665,6 +665,14 @@ if (.runThisTest) {
         other <- list_sexp_assign(l)
         checkIdentical(l, other)
     }
+
+    test.logical.vector.from.bool <- function() {
+        checkIdentical(logical_vector_from_bool(), TRUE)
+    }
+
+    test.logical.vector.from.bool.assign <- function() {
+        checkIdentical(logical_vector_from_bool_assign(), TRUE)
+    }
 
 }