Added string as a primitive type to the type system.

This will make it less hacky to represent proper strings in our AST model.

src/AST/CppTypePrinter.cs

@@ -142,6 +142,20 @@ namespace CppSharp.AST
                 case PrimitiveType.IntPtr: return "void*";
                 case PrimitiveType.UIntPtr: return "uintptr_t";
                 case PrimitiveType.Null: return PrintFlavorKind == CppTypePrintFlavorKind.Cpp ? "std::nullptr_t" : "NULL";
+                case PrimitiveType.String:
+                {
+                    switch (PrintFlavorKind)
+                    {
+                    case CppTypePrintFlavorKind.C:
+                        return "const char*";
+                    case CppTypePrintFlavorKind.Cpp:
+                        return "std::string";
+                    case CppTypePrintFlavorKind.ObjC:
+                        return "NSString";;
+                    default:
+                        throw new ArgumentOutOfRangeException();
+                    }
+                }
             }
 
             throw new NotSupportedException();

src/AST/Type.cs

@@ -1132,7 +1132,8 @@ namespace CppSharp.AST
         LongDouble,
         Float128,
         IntPtr,
-        UIntPtr
+        UIntPtr,
+        String
     }
 
     /// <summary>

src/Generator/Generators/CLI/CLITypePrinter.cs

@@ -232,6 +232,7 @@ namespace CppSharp.Generators.CLI
                 case PrimitiveType.IntPtr: return "IntPtr";
                 case PrimitiveType.UIntPtr: return "UIntPtr";
                 case PrimitiveType.Null: return "void*";
+                case PrimitiveType.String: return "System::String";
             }
 
             throw new NotSupportedException();

src/Generator/Generators/CSharp/CSharpTypePrinter.cs

@@ -558,6 +558,7 @@ namespace CppSharp.Generators.CSharp
                 case PrimitiveType.IntPtr: return IntPtrType;
                 case PrimitiveType.UIntPtr: return "global::System.UIntPtr";
                 case PrimitiveType.Null: return "void*";
+                case PrimitiveType.String: return "string";
             }
 
             throw new NotSupportedException();