Fix a few obvious code issues

Author: mgreter

include/sass2scss.h

@@ -80,7 +80,7 @@ namespace Sass
 	};
 
 	// function only available in c++ code
-	char* sass2scss (const string sass, const int options);
+	char* sass2scss (const string& sass, const int options);
 
 }
 // EO namespace

src/ast.cpp

@@ -32,7 +32,7 @@ namespace Sass {
   bool Compound_Selector::operator< (const Compound_Selector& rhs) const
   {
     size_t L = std::min(length(), rhs.length());
-    for (size_t i = 0; i < L && i < L; ++i)
+    for (size_t i = 0; i < L; ++i)
     {
       Simple_Selector* l = (*this)[i];
       Simple_Selector* r = rhs[i];
@@ -568,7 +568,7 @@ namespace Sass {
     //for (auto l : lset) { cerr << "l: " << l << endl; }
     //for (auto r : rset) { cerr << "r: " << r << endl; }
 
-    if (lset.size() == 0) return true;
+    if (lset.empty()) return true;
     // return true if rset contains all the elements of lset
     return includes(rset.begin(), rset.end(), lset.begin(), lset.end());
 

src/color_maps.cpp

@@ -613,7 +613,7 @@ namespace Sass {
     return 0;
   }
 
-  const Color* name_to_color(const std::string key)
+  const Color* name_to_color(const std::string& key)
   {
     return name_to_color(key.c_str());
   }

src/color_maps.hpp

@@ -323,7 +323,7 @@ namespace Sass {
   extern const std::map<const char*, const Color*, map_cmp_str> names_to_colors;
 
   extern const Color* name_to_color(const char*);
-  extern const Color* name_to_color(const std::string);
+  extern const Color* name_to_color(const std::string&);
   extern const char* color_to_name(const int);
   extern const char* color_to_name(const Color&);
   extern const char* color_to_name(const double);

src/sass2scss.cpp

@@ -777,7 +777,7 @@ namespace Sass
 	}
 
 	// the main converter function for c++
-	char* sass2scss (const string sass, const int options)
+	char* sass2scss (const string& sass, const int options)
 	{
 
 		// local variables