Added explicit (const_)string_proxy/SEXP comparisons to resolve ambiguity

[dcdillon]

This fixes compile failures in readr, readxl, and rpg

[eddelbuettel]

... and tidyr. Thanks for fixing it and submitting a PR while my rev.dep. check is still running!

[eddelbuettel]

Ok, I checked and this fixed readr, readxl, rpg and tidyr. We still have package icd9 failing with:

** libs
ccache gcc -I/usr/share/R/include -DNDEBUG   -I"/usr/local/lib/R/site-library/Rcpp/include"  -fopenmp -fpic  -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -g  -O3 -Wall -pipe
 -pedantic -std=gnu99 -c cutil.c -o cutil.o
ccache g++ -I/usr/share/R/include -DNDEBUG   -I"/usr/local/lib/R/site-library/Rcpp/include"  -I. -fopenmp -std=c++11 -fpic  -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -g  
-O3 -Wall -pipe -Wno-unused -pedantic -c is.cpp -o is.o
ccache g++ -I/usr/share/R/include -DNDEBUG   -I"/usr/local/lib/R/site-library/Rcpp/include"  -I. -fopenmp -std=c++11 -fpic  -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -g  
-O3 -Wall -pipe -Wno-unused -pedantic -c manip.cpp -o manip.o
manip.cpp: In function ‘Rcpp::String icd9AddLeadingZeroesMajorSingle(Rcpp::String)’:
manip.cpp:25:12: error: ambiguous overload for ‘operator==’ (operand types are ‘Rcpp::String’ and ‘SEXP’)
  if (major == NA_STRING) {
            ^
manip.cpp:25:12: note: candidates are:
In file included from /usr/local/lib/R/site-library/Rcpp/include/Rcpp/Vector.h:67:0,
                 from /usr/local/lib/R/site-library/Rcpp/include/Rcpp.h:38,
                 from ./convert.h:22,
                 from manip.cpp:20:
/usr/local/lib/R/site-library/Rcpp/include/Rcpp/String.h:414:14: note: bool Rcpp::String::operator==(const Rcpp::String&) const
         bool operator==( const Rcpp::String& other) const {
              ^
/usr/local/lib/R/site-library/Rcpp/include/Rcpp/String.h:429:14: note: bool Rcpp::String::operator==(const const_StringProxy&) const
         bool operator==( const const_StringProxy& other) const {
              ^
/usr/lib/R/etc/Makeconf:143: recipe for target 'manip.o' failed
make: *** [manip.o] Error 1
make: *** Waiting for unfinished jobs....

[thirdwing]

I think add those lines below into String.h should fix icd9.

bool operator==( SEXP other) const {                                
    return get_sexp() == other;                                     
}                                                                   

bool operator!=( SEXP other) const {                                
    return get_sexp() != other;                                     
 }

[eddelbuettel]

Nice work, @thirdwing !

When I looked as vector/string_proxy.h I got into trouble with the forward reference. Going to String.h works as you say (and we do indeed need get_sexp() instead of get().

@dcdillon Do you want to add this to the PR or shall I just add it after merging?

edd@max:/tmp/rcpp-tmp/Rcpp$ diff -u ~/git/rcpp/inst/include/Rcpp/String.h inst/include/Rcpp/String.h                                                                                                                 
--- /home/edd/git/rcpp/inst/include/Rcpp/String.h       2015-09-08 09:59:23.570918337 -0500
+++ inst/include/Rcpp/String.h  2015-09-09 05:54:04.478869310 -0500
@@ -438,6 +438,14 @@
             return strcmp( get_cstring(), other.get_cstring() ) > 0;
         }

+        bool operator==( SEXP other ) const {
+            return get_sexp() == other;
+        }
+
+        bool operator!=( SEXP other ) const {
+            return get_sexp() != other;
+        }
+
     private:

         /** the CHARSXP this String encapsulates */
edd@max:/tmp/rcpp-tmp/Rcpp$ 

Ah shucks, I'll just do it and then start a new test run ...