Support using value types (structs) in Peachpie

[roberthusak]

Sample C# code:

namespace ClassLibrary
{
    public struct MyStruct
    {
        public int Value;

        public MyStruct(int value) {
            Value = value;
        }
    }
}

Sample PHP code:

function test_struct(ClassLibrary\MyStruct $typed, $untyped) {
  echo $typed->Value;
  echo $untyped->Value;
}

test_struct(new ClassLibrary\MyStruct(42), new ClassLibrary\MyStruct(43));

Thanks to boxing, echo $untyped->Value currently works, but when using a value type directly (e.g. constructing it, converting to and from it etc.), NotImplementedException is thrown.

---

• [x] getting/setting properties on value types
• [x] calling methods on value types
• [x] constructing value types
• [ ] calling non-readonly methods, should change the value (through boxing it in StructBox<TValue>)
  • see PhpValue.FromStruct
  • extend ConvertExpression
  • extend PhpValue.ToClr
• [ ] write some tests

[jakubmisek]

I would add, that also calling methods on structs should be supported; additionally, when calling non-readonly method then the value must be copied back.

// the following might have a side effect,
// the unboxed $value should be copied back to $value or there should not be any boxing at all
$value->method();

[jakubmisek]

@roberthusak is it alright now?

[roberthusak]

@jakubmisek Nice, the original sample works well now 👍 Certain operations still don't compile or work though, here is a more detailed use case:

C#:

namespace ClassLibrary
{
    public struct MyStruct
    {
        public int Value;

        public MyStruct(int value) {
            Value = value;
        }

        public void SetValue(int value) {
            Value = value;
        }
    }
}

PHP:

function print_structs(ClassLibrary\MyStruct $typed, $untyped) {
  echo "{$typed->Value},{$untyped->Value}\n";
}

function test_struct(ClassLibrary\MyStruct $typed, $untyped) {
  print_structs($typed, $untyped);  // 42,43

  $typed->Value = 52;
  $untyped->Value = 53;
  print_structs($typed, $untyped);  // 52,53

  $typed->SetValue(62);
  $untyped->SetValue(63);
  print_structs($typed, $untyped);  // 62,63
}

$s = new ClassLibrary\MyStruct(42);
test_struct($s, new ClassLibrary\MyStruct(43));

[jakubmisek]

@roberthusak that's those non-readonly methods, adding to the checklist