Added conditional compilation and Const namespace with OS name

base_string.cpp

@@ -476,9 +476,22 @@ struct String_Replace {
   String replace;
 };
 
-// function String
-// string_replace(String string, Array<String_Replace> pairs){
-//   for(int i = 0; i < string.len; i++){
+function String
+string_replace(Arena *arena, String string, Array<String_Replace> pairs){
+  Scratch scratch(arena);
+  String_Builder builder = {scratch};
+  for(int i = 0; i < string.len; i++){
+    For(pairs){
+      String current = string_skip(string, i);
+      current = string_get_prefix(current, it.find.len);
+      if(current == it.find){
+        builder.append_data(it.replace.str, it.replace.len);
+        i += it.find.len;
+        continue;
+      }
+    }
 
-//   }
-// }
+   builder.append_data(string.str + i, 1);
+  }
+  return string_flatten(arena, &builder);
+}