YAPC::EU 2018 Glasgow Update!

Task/String-interpolation--included-/C++/string-interpolation--included-.cpp

@@ -1,11 +1,44 @@
-#include <string>
-#include <iostream>
+// Variable argument template
 
-int main( ) {
-   std::string original( "Mary had a X lamb." ) , toBeReplaced( "X" ) ,
-      replacement ( "little" ) ;
-   std::string newString = original.replace( original.find( "X" ) ,
-	 toBeReplaced.length( ) , replacement ) ;
-   std::cout << "String after replacement: " << newString << " \n" ;
-   return 0 ;
+#include <string>
+#include <vector>
+
+using std::string;
+using std::vector;
+
+template<typename S, typename... Args>
+string interpolate( const S& orig , const Args&... args)
+{
+   string out(orig);
+
+   // populate vector from argument list
+   auto va = {args...};
+   vector<string> v{va};
+
+   size_t i = 1;
+
+   for( string s: v)
+     {
+       string is = std::to_string(i);
+       string t = "{" +  is + "}";  // "{1}", "{2}", ...
+       try
+	 {
+	   auto pos = out.find(t);
+
+	   if ( pos != out.npos)  // found token
+	     {
+	       out.erase(pos, t.length()); //erase token
+	       out.insert( pos, s);       // insert arg
+	     }
+
+	   i++;                           // next
+	 }
+	 catch( std::exception& e)
+	   {
+	     std::cerr << e.what() << std::endl;
+	   }
+
+     } // for
+
+   return out;
 }