[Rcpp-commits] r2055 - papers/rjournal

[noreply at r-forge.r-project.org]

Author: edd
Date: 2010-08-29 01:40:52 +0200 (Sun, 29 Aug 2010)
New Revision: 2055

Modified:
   papers/rjournal/EddelbuettelFrancois.tex
Log:
added (simplified) Rcpp::as<> signature
standardized code examples w.r.t. semicolons


Modified: papers/rjournal/EddelbuettelFrancois.tex
===================================================================
--- papers/rjournal/EddelbuettelFrancois.tex	2010-08-28 22:11:27 UTC (rev 2054)
+++ papers/rjournal/EddelbuettelFrancois.tex	2010-08-28 23:40:52 UTC (rev 2055)
@@ -331,9 +331,9 @@
 code more concisely:
 
 \begin{example}
-CharacterVector ab(2) ;
-ab[0] = "foo" ;
-ab[1] = "bar" ;
+CharacterVector ab(2);
+ab[0] = "foo";
+ab[1] = "bar";
 \end{example}
 
 \section{R and C++ data interchange}
@@ -353,7 +353,7 @@
 
 \begin{example}
 template <typename T> 
-SEXP wrap(const T& object) ;
+SEXP wrap(const T& object);
 \end{example}
 
 The templated function takes a reference to a `wrappable` 
@@ -392,9 +392,9 @@
 m1["foo"] = 1; m1["bar"] = 2;
 m2["foo"] = 1; m2["bar"] = 2; m2["baz"] = 3;
 
-v.push_back( m1) ;
-v.push_back( m2) ;
-Rcpp::wrap( v ) ;
+v.push_back( m1);
+v.push_back( m2);
+Rcpp::wrap( v );
 \end{example}
 
 The code creates a list of two named vectors, equal to the 
@@ -408,7 +408,13 @@
 \subsection{R to C++ : as}
 
 The reversed conversion is implemented by variations of the 
-\code{Rcpp::as} template. It offers less flexibility and currently
+\code{Rcpp::as} template whose signature is:
+\begin{example}
+template <typename T> 
+T as(SEXP x);
+\end{example}
+
+It offers less flexibility and currently
 handles conversion of R objects into primitive types (bool, int, std::string, ...), 
 STL vectors of primitive types  (\code{std::vector<bool>}, 
 \code{std::vector<double>}, etc ...) and arbitrary types that offer 
@@ -416,6 +422,8 @@
 be fully or partially specialized to manage conversion of R data 
 structures to third-party types.
 
+
+
 \subsection{Implicit use of converters}
 
 The converters offered by \code{wrap} and \code{as} provide a very 
@@ -431,19 +439,19 @@
 // assuming the global environment contains 
 // a variable 'x' that is a numeric vector
 Rcpp::Environment global = 
-\ \ \ \ Rcpp::Environment::global_env()
+\ \ \ \ Rcpp::Environment::global_env();
 
 // extract a std::vector<double> from 
 // the global environment
-std::vector<double> vx = global["x"] ;
+std::vector<double> vx = global["x"];
 
 // create a map<string,string>
-std::map<std::string,std::string> map ;
-map["foo"] = "oof" ;
-map["bar"] = "rab" ;
+std::map<std::string,std::string> map;
+map["foo"] = "oof";
+map["bar"] = "rab";
 
 // push the STL map to R
-global["y"] = map ;
+global["y"] = map;
 \end{example}
 
 In the first part of the example, the code extracts a 
@@ -512,10 +520,10 @@
 \ \ LCONS( install("rnorm"), 
 \ \ \ \ CONS(ScalarInteger(10), 
 \ \ \ \ \ \ CONS(ScalarReal(100.0),R_NilValue))));
-SET_TAG( CDDR(call), install("sd") ) ;
+SET_TAG( CDDR(call), install("sd") );
 SEXP res = PROTECT(eval(call, R_GlobalEnv));
-UNPROTECT(2) ;
-return res ;
+UNPROTECT(2);
+return res;
     \end{example}
   \end{minipage}
   \caption{\pkg{Rcpp} versus the R API: Four ways of calling \code{rnorm(10L, sd=100)} in C / C++. 
@@ -631,14 +639,14 @@
 \begin{example}
 > src <- '
 +   Rcpp::List input(data); 
-+   Rcpp::Function f(fun) ;
++   Rcpp::Function f(fun);
 +   Rcpp::List output(input.size());
 +   std::transform( 
 +   	input.begin(), input.end(), 
 +   	output.begin(), 
-+   	f ) ;
-+   output.names() = input.names() ;
-+   return output ;
++   	f );
++   output.names() = input.names();
++   return output;
 +   '
 > cpp_lapply <- cfunction(
 + \ \ signature(data="list", fun = "function"), 
@@ -684,10 +692,10 @@
 
 \begin{example}
 > fun <- cfunction(signature(x = "integer"),'
-+  int dx = as<int>(x) ;
++  int dx = as<int>(x);
 +   if( dx > 10 ) 
 +      throw std::range_error("too big") ;
-+   return wrap(dx*dx) ;
++   return wrap(dx*dx);
 + ', Rcpp = TRUE, 
 +  includes = "using namespace Rcpp;" )
 > tryCatch( fun(12), 
@@ -749,19 +757,19 @@
 RcppExport SEXP convolve4cpp(SEXP a, SEXP b)\{
     Rcpp::NumericVector xa(a);
     Rcpp::NumericVector xb(b);
-    int n_xa = xa.size() ;
-    int n_xb = xb.size() ;
+    int n_xa = xa.size();
+    int n_xb = xb.size();
     Rcpp::NumericVector xab(n_xa + n_xb - 1);
     
-    double* pa = xa.begin() ;
-    double* pb = xb.begin() ;
-    double* pab = xab.begin() ;
+    double* pa = xa.begin();
+    double* pb = xb.begin();
+    double* pab = xab.begin();
     int i,j=0; 
     for (i = 0; i < n_xa; i++)
         for (j = 0; j < n_xb; j++) 
             pab[i + j] += pa[i] * pb[j];
 
-    return xab ;
+    return xab;
 \}
 \end{example}