string index function

Author: wonja

context.cpp

@@ -363,6 +363,7 @@ namespace Sass {
     register_function(ctx, quote_sig, sass_quote, env);
     register_function(ctx, str_length_sig, str_length, env);
     register_function(ctx, str_insert_sig, str_insert, env);
+    register_function(ctx, str_index_sig, str_index, env);
     // Number Functions
     register_function(ctx, percentage_sig, percentage, env);
     register_function(ctx, round_sig, round, env);

functions.cpp

@@ -752,6 +752,25 @@ namespace Sass {
 
     }
 
+    Signature str_index_sig = "str-index($string, $substring)";
+    BUILT_IN(str_index)
+    {
+      String_Constant* s = ARG("$string", String_Constant);
+      String_Constant* t = ARG("$substring", String_Constant);
+      string str = s->value();
+      str = unquote(str);
+      string substr = t->value();
+      substr = unquote(substr);
+
+      size_t c_index = str.find(substr);
+      if(c_index == string::npos) {
+        return new (ctx.mem) Null(path, position);
+      }
+      size_t index = UTF_8::code_point_count(str, 0, c_index + 1);
+
+      return new (ctx.mem) Number(path, position, index);
+    }
+
     ///////////////////
     // NUMBER FUNCTIONS
     ///////////////////

functions.hpp

@@ -66,6 +66,7 @@ namespace Sass {
     extern Signature quote_sig;
     extern Signature str_length_sig;
     extern Signature str_insert_sig;
+    extern Signature str_index_sig;
     extern Signature percentage_sig;
     extern Signature round_sig;
     extern Signature ceil_sig;
@@ -119,6 +120,7 @@ namespace Sass {
     BUILT_IN(sass_quote);
     BUILT_IN(str_length);
     BUILT_IN(str_insert);
+    BUILT_IN(str_index);
     BUILT_IN(percentage);
     BUILT_IN(round);
     BUILT_IN(ceil);