initial return type handling

examples/helloworld/src/lib.rs

@@ -11,6 +11,16 @@ fn hello_world() {
     printf("Hello world, Rust!");
 }
 
+#[ivory_export]
+fn add1(input: i64) -> i64 {
+    input + 1
+}
+
+#[ivory_export]
+fn format_hello(other: String) -> String {
+    format!("Hello {}", other)
+}
+
 ivory_module!({
     name: "demo",
     version: "0.0.1",

ivory/macro/src/lib.rs

@@ -89,6 +89,12 @@ fn export_fn(item: ItemFn) -> TokenStream {
             let mut args = data.args();
             #(#arg_cast);*
             let result = #body;
+
+            let php_val = ::ivory::zend::PhpVal::from(result);
+            let zval = ::ivory::zend::ZVal::from(php_val);
+            unsafe {
+                *retval = zval
+            };
         }
     }
 }

ivory/src/zend/zval.rs

@@ -7,7 +7,7 @@ use std::mem::size_of;
 use std::os::raw::c_char;
 use std::str;
 
-use ivory_sys::{zend_execute_data, zend_string, zval};
+use ivory_sys::*;
 
 use crate::CastError;
 
@@ -274,6 +274,12 @@ impl_from_phpval!(f64, Double);
 impl_from_phpval!(bool, Bool);
 impl_from_phpval!(String, String);
 
+impl From<()> for PhpVal {
+    fn from(_input: ()) -> Self {
+        PhpVal::Null
+    }
+}
+
 impl<T: Into<PhpVal>> From<Option<T>> for PhpVal {
     fn from(input: Option<T>) -> Self {
         match input {
@@ -314,3 +320,22 @@ impl<K: Into<ArrayKey> + Hash + Eq + Ord, T: Into<PhpVal>> From<HashMap<K, T>> f
         vec.into()
     }
 }
+
+impl From<PhpVal> for ZVal {
+    fn from(input: PhpVal) -> Self {
+        match input {
+            PhpVal::Long(val) => ZVal(zval {
+                value: zend_value { lval: val },
+                u1: _zval_struct__bindgen_ty_1 {
+                    v: _zval_struct__bindgen_ty_1__bindgen_ty_1 {
+                        type_: ZValType::Long as zend_uchar,
+                        type_flags: 0,
+                        u: _zval_struct__bindgen_ty_1__bindgen_ty_1__bindgen_ty_1 { extra: 0 },
+                    },
+                },
+                u2: _zval_struct__bindgen_ty_2 { extra: 0 },
+            }),
+            _ => unimplemented!(),
+        }
+    }
+}