Introduce function reference value types

Cargo.toml

@@ -13,7 +13,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 cargo-php = "0.1.7"
-ext-php-rs = "0.10.1"
+ext-php-rs = {version = "0.10.1", features = ["closure"] }
 wasmer = { version = "4.1.0", default-features = true, features = ["sys"] }
 wasmer-compiler = "4.1.0"
 

ext-wasm.stubs.php

@@ -16,7 +16,7 @@ public function __set(string $accessor, mixed $value): void {}
     class InstanceBuilder {
         public static function fromWat(string $wat): \Wasm\InstanceBuilder {}
 
-        public function import(array $imports): void {}
+        public function import(Imports $imports): void {}
 
         public function build(): \Wasm\WasmInstance {}
     }

tests/ImportsTest.php

@@ -70,6 +70,36 @@ public function test_it_imports_simple_globals() {
         self::assertSame([32], $instance->read_g());
     }
 
+
+    public function test_it_can_call_external_function() {
+        $result = (object)['current' => false];
+
+        $imports = Imports::create();
+        $imports->define('env', 'greet', Type\Global::immutable(
+            function () use ($result) {
+                $result->current = true;
+            }
+        ));
+
+        $builder = $this->createBuilderFromWat(
+            <<<'EOWAT'
+            (module
+                (import "env" "greet" (func $greet))
+                (func
+                    call $greet
+                )
+                (start 1) ;; run the first function automatically
+            )
+            EOWAT
+        );
+
+
+        $builder->import($imports);
+        $instance = $builder->build();
+
+        self::assertTrue($result->current);
+    }
+
     private function createBuilderFromWat(?string $wat = null): InstanceBuilder
     {
         return InstanceBuilder::fromWat($wat ?? <<<'EOWAT'