diff --git a/src/main.rs b/src/main.rs
index 944cb67..8c631d7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,7 +1,7 @@
 use wabt;
 use wasmi::{
-   Error, Externals, FuncInstance, FuncRef, ImportsBuilder, ModuleImportResolver, ModuleInstance,
-   RuntimeArgs, RuntimeValue, Signature, Trap, ValueType,
+    Error, Externals, FuncInstance, FuncRef, ImportsBuilder, ModuleImportResolver, ModuleInstance,
+    RuntimeArgs, RuntimeValue, Signature, Trap, ValueType,
 };
 
 mod wasm_sys;
@@ -11,102 +11,103 @@ pub const KILL: usize = 0;
 
 struct HostFunctions;
 impl HostFunctions {
-   fn check_signature(&self, index: usize, signature: &Signature) -> bool {
-      let (params, ret_ty): (&[ValueType], Option<ValueType>) = match index.into() {
-         SysCall::KILL => (&[ValueType::I32, ValueType::I32], Some(ValueType::I32)),
-         _ => return false,
-      };
-      signature.params() == params && signature.return_type() == ret_ty
-   }
+    fn check_signature(&self, index: usize, signature: &Signature) -> bool {
+        let (params, ret_ty): (&[ValueType], Option<ValueType>) = match index.into() {
+            SysCall::KILL => (&[ValueType::I32, ValueType::I32], Some(ValueType::I32)),
+            SysCall::EMPTY => (&[], None),
+            _ => return false,
+        };
+        signature.params() == params && signature.return_type() == ret_ty
+    }
 }
-
 impl Externals for HostFunctions {
-   fn invoke_index(
-      &mut self,
-      index: usize,
-      args: RuntimeArgs,
-   ) -> Result<Option<RuntimeValue>, Trap> {
-      match index.into() {
-         SysCall::KILL => {
-            let a: u32 = args.nth_checked(0)?;
-            let b: u32 = args.nth_checked(1)?;
-            let result = a + b;
+    fn invoke_index(
+        &mut self,
+        index: usize,
+        args: RuntimeArgs,
+    ) -> Result<Option<RuntimeValue>, Trap> {
+        match index.into() {
+            SysCall::KILL => {
+                let a: u32 = args.nth_checked(0)?;
+                let b: u32 = args.nth_checked(1)?;
+                let result = a + b;
 
-            Ok(Some(RuntimeValue::I32(result as i32)))
-         }
-         SysCall::CONSOLE_RESET => {}
-         SysCall::CONSOLE_IN => {}
-         SysCall::CONSOLE_OUT => {}
-         SysCall::CONSOLE_GET_TITLE => {}
-         SysCall::CONSOLE_SET_TITLE => {}
-
-         _ => panic!("Unimplemented function at {}", index),
-      }
-   }
+                Ok(Some(RuntimeValue::I32(result as i32)))
+            }
+            SysCall::EMPTY => Ok(None),
+            // SysCall::CONSOLE_RESET => {}
+            // SysCall::CONSOLE_IN => {}
+            // SysCall::CONSOLE_OUT => {}
+            // SysCall::CONSOLE_GET_TITLE => {}
+            // SysCall::CONSOLE_SET_TITLE => {}
+            _ => panic!("Unimplemented function at {}", index),
+        }
+    }
 }
 impl ModuleImportResolver for HostFunctions {
-   fn resolve_func(&self, field_name: &str, signature: &Signature) -> Result<FuncRef, Error> {
-      let index = match field_name {
-         "add" => SysCall::KILL as usize,
-         _ => {
+    fn resolve_func(&self, field_name: &str, signature: &Signature) -> Result<FuncRef, Error> {
+        let index = match field_name {
+            "add" => SysCall::KILL as usize,
+            "empty" => SysCall::EMPTY as usize,
+            _ => {
+                return Err(Error::Instantiation(format!(
+                    "Export {} not found",
+                    field_name
+                )))
+            }
+        };
+
+        if !self.check_signature(index, signature) {
             return Err(Error::Instantiation(format!(
-               "Export {} not found",
-               field_name
-            )))
-         }
-      };
+                "Export {} has a bad signature",
+                field_name
+            )));
+        }
 
-      if !self.check_signature(index, signature) {
-         return Err(Error::Instantiation(format!(
-            "Export {} has a bad signature",
-            field_name
-         )));
-      }
-
-      Ok(FuncInstance::alloc_host(
-         Signature::new(&[ValueType::I32, ValueType::I32][..], Some(ValueType::I32)),
-         index,
-      ))
-   }
+        Ok(FuncInstance::alloc_host(
+            Signature::new(&[ValueType::I32, ValueType::I32][..], Some(ValueType::I32)),
+            index,
+        ))
+    }
 }
 
 fn main() {
-   // Parse WAT (WebAssembly Text format) into wasm bytecode.
-   let wasm_binary = wabt::wat2wasm(include_str!("../wasm/test.wat"));
+    // Parse WAT (WebAssembly Text format) into wasm bytecode.
+    let wasm_binary = wabt::wat2wasm(include_str!("../wasm/test.wat"));
 
-   let wasm_binary = match wasm_binary {
-      Ok(abc) => abc,
-      Err(abc) => {
-         println!("{}", abc);
-         return;
-      }
-   };
+    let wasm_binary = match wasm_binary {
+        Ok(abc) => abc,
+        Err(abc) => {
+            println!("{}", abc);
+            return;
+        }
+    };
 
-   // .expect("failed to parse wat");
+    // .expect("failed to parse wat");
 
-   // Load wasm binary and prepare it for instantiation.
-   let module = wasmi::Module::from_buffer(&wasm_binary).expect("failed to load wasm");
+    // Load wasm binary and prepare it for instantiation.
+    let module = wasmi::Module::from_buffer(&wasm_binary).expect("failed to load wasm");
 
-   let imports = ImportsBuilder::new().with_resolver("host", &HostFunctions);
+    let imports = ImportsBuilder::new().with_resolver("host", &HostFunctions);
 
-   // Instantiate a module with empty imports and
-   // assert that there is no `start` function.
-   let instance = ModuleInstance::new(&module, &imports)
-      .expect("failed to instantiate wasm module")
-      .assert_no_start();
+    // Instantiate a module with empty imports and
+    // assert that there is no `start` function.
+    let instance = ModuleInstance::new(&module, &imports)
+        .expect("failed to instantiate wasm module")
+        .assert_no_start();
 
-   // Finally, invoke the exported function "test" with no parameters
-   // and empty external function executor.
-   let result: i32 = instance
-      .invoke_export("main", &[], &mut HostFunctions)
-      // .with_resolver(&mut HostFunctions)
-      .expect("failed to execute export")
-      .unwrap()
-      .try_into()
-      .unwrap();
+    // Finally, invoke the exported function "test" with no parameters
+    // and empty external function executor.
+    let result: i32 = instance
+        .invoke_export("main", &[], &mut HostFunctions)
+        // .with_resolver(&mut HostFunctions)
+        .expect("failed to execute export")
+        .unwrap()
+        .try_into()
+        .unwrap();
 
-   println!(
-      "{:?}",
-      result // .unwrap()
-   );
+    println!(
+        "{:?}",
+        result // .unwrap()
+    );
 }
diff --git a/src/wasm_sys.rs b/src/wasm_sys.rs
index bbc4d63..f6c3232 100644
--- a/src/wasm_sys.rs
+++ b/src/wasm_sys.rs
@@ -1,4 +1,5 @@
 macro_rules! syscall_enum {
+   () => {};
    (@get_last $Variant:ident) => {
       Self::$Variant
    };
@@ -71,9 +72,6 @@ syscall_enum! {
    SOCKET_SEND=42,
    SOCKET_RECEIVE=43,
 
-
-
-
    // Security Syscalls
    ENCRYPT=50,
    EMPTY=0xFFFF,
diff --git a/wasm/test.wat b/wasm/test.wat
index e12d5d5..77f65c4 100644
--- a/wasm/test.wat
+++ b/wasm/test.wat
@@ -1,6 +1,8 @@
 (module
       (import "host" "add" (func $add (param i32 i32)(result i32)))
+      (; (import "host" "empty" (func $empty)) ;)
       (func (export "main") (result i32)
+            (; (call $empty) ;)
             (call $add (i32.const 123) (i32.const 456))
       )
 )