diff --git a/examples/custom_types_and_methods.rs b/examples/custom_types_and_methods.rs
index 66a9b2ea..65cf3225 100644
--- a/examples/custom_types_and_methods.rs
+++ b/examples/custom_types_and_methods.rs
@@ -1,5 +1,5 @@
 extern crate rhai;
-use rhai::{Engine, FnRegister};
+use rhai::{Engine, RegisterFn};
 
 #[derive(Clone)]
 struct TestStruct {
diff --git a/examples/repl.rs b/examples/repl.rs
index cfc56596..145c288b 100644
--- a/examples/repl.rs
+++ b/examples/repl.rs
@@ -3,7 +3,7 @@ extern crate rhai;
 use std::fmt::Display;
 use std::process::exit;
 use std::io::{stdin, stdout, Write};
-use rhai::{Engine, FnRegister, Scope};
+use rhai::{Engine, RegisterFn, Scope};
 
 fn showit<T: Display>(x: &mut T) -> () {
     println!("{}", x)
diff --git a/examples/rhai_runner.rs b/examples/rhai_runner.rs
index e4c4063d..6637844a 100644
--- a/examples/rhai_runner.rs
+++ b/examples/rhai_runner.rs
@@ -2,7 +2,7 @@ use std::env;
 use std::fmt::Display;
 
 extern crate rhai;
-use rhai::{Engine, FnRegister};
+use rhai::{Engine, RegisterFn};
 
 fn showit<T: Display>(x: &mut T) -> () {
     println!("{}", x)
diff --git a/examples/simple_fn.rs b/examples/simple_fn.rs
index 55b1cb72..04b55b68 100644
--- a/examples/simple_fn.rs
+++ b/examples/simple_fn.rs
@@ -1,5 +1,5 @@
 extern crate rhai;
-use rhai::{Any, Engine, RegisterFn};
+use rhai::{Engine, RegisterFn};
 
 fn add(x: i64, y: i64) -> i64 {
     x + y
diff --git a/src/engine.rs b/src/engine.rs
index 43c8137d..7abbd746 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -27,6 +27,28 @@ pub enum EvalAltResult {
     Return(Box<Any>),
 }
 
+impl PartialEq for EvalAltResult {
+    fn eq(&self, other: &Self) -> bool {
+        use EvalAltResult::*;
+
+        match (self, other) {
+            (&ErrorFunctionNotFound, &ErrorFunctionNotFound) => true,
+            (&ErrorFunctionArgMismatch, &ErrorFunctionArgMismatch) => true,
+            (&ErrorFunctionCallNotSupported, &ErrorFunctionCallNotSupported) => true,
+            (&ErrorIndexMismatch, &ErrorIndexMismatch) => true,
+            (&ErrorIfGuardMismatch, &ErrorIfGuardMismatch) => true,
+            (&ErrorVariableNotFound(ref a), &ErrorVariableNotFound(ref b)) => a == b,
+            (&ErrorFunctionArityNotSupported, &ErrorFunctionArityNotSupported) => true,
+            (&ErrorAssignmentToUnknownLHS, &ErrorAssignmentToUnknownLHS) => true,
+            (&ErrorMismatchOutputType, &ErrorMismatchOutputType) => true,
+            (&ErrorCantOpenScriptFile, &ErrorCantOpenScriptFile) => true,
+            (&InternalErrorMalformedDotExpression, &InternalErrorMalformedDotExpression) => true,
+            (&LoopBreak, &LoopBreak) => true,
+            _ => false,
+        }
+    }
+}
+
 impl Error for EvalAltResult {
     fn description(&self) -> &str {
         match *self {
@@ -121,6 +143,12 @@ impl Engine {
         ident: String,
         args: Vec<&mut Box<Any>>,
     ) -> Result<Box<Any>, EvalAltResult> {
+        println!(
+            "Trying to call function {:?} with args {:?}",
+            ident,
+            args.iter().map(|x| (***x).type_id()).collect::<Vec<_>>()
+        );
+
         let spec = FnSpec {
             ident: ident.clone(),
             args: Some(
@@ -137,11 +165,26 @@ impl Engine {
             .ok_or(EvalAltResult::ErrorFunctionNotFound)
             .and_then(move |f| match *f {
                 FnIntExt::Ext(ref f) => f(args),
-                FnIntExt::Int(_) => unreachable!(),
+                FnIntExt::Int(ref f) => {
+                    let mut scope = Scope::new();
+                    scope.extend(
+                        f.params
+                            .iter()
+                            .cloned()
+                            .zip(args.iter().map(|x| (&**x).clone())),
+                    );
+
+                    match self.eval_stmt(&mut scope, &*f.body) {
+                        Err(EvalAltResult::Return(x)) => Ok(x),
+                        other => other,
+                    }
+                }
             })
     }
 
     pub fn register_fn_raw(&mut self, ident: String, args: Option<Vec<TypeId>>, f: Box<FnAny>) {
+        println!("Register; {:?} with args {:?}", ident, args,);
+
         let spec = FnSpec { ident, args };
 
         self.fns.insert(spec, FnIntExt::Ext(f));
@@ -247,7 +290,12 @@ impl Engine {
             .and_then(move |(idx, &mut (_, ref mut val))| map(val).map(|val| (idx, val)))
     }
 
-    fn array_value(&self, scope: &mut Scope, id: &str, idx: &Expr) -> Result<(usize, usize, Box<Any>), EvalAltResult> {
+    fn array_value(
+        &self,
+        scope: &mut Scope,
+        id: &str,
+        idx: &Expr,
+    ) -> Result<(usize, usize, Box<Any>), EvalAltResult> {
         let idx_boxed = self.eval_expr(scope, idx)?
             .downcast::<i64>()
             .map_err(|_| EvalAltResult::ErrorIndexMismatch)?;
@@ -307,7 +355,10 @@ impl Engine {
                 Expr::Identifier(ref id) => {
                     let get_fn_name = "get$".to_string() + id;
                     self.call_fn_raw(get_fn_name, vec![this_ptr])
-                        .and_then(|mut v| self.set_dot_val_helper(&mut v, inner_rhs, source_val))
+                        .and_then(|mut v| {
+                            self.set_dot_val_helper(&mut v, inner_rhs, source_val)
+                                .map(|_| v) // Discard Ok return value
+                        })
                         .and_then(|mut v| {
                             let set_fn_name = "set$".to_string() + id;
 
diff --git a/src/lib.rs b/src/lib.rs
index 10ac21f6..2e5947f1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -17,7 +17,7 @@
 //! And the Rust part:
 //!
 //! ```rust
-//! use rhai::{FnRegister, Engine};
+//! use rhai::{Engine, RegisterFn};
 //!
 //! fn compute_something(x: i64) -> bool {
 //!	    (x % 40) == 0
diff --git a/src/tests/arrays.rs b/src/tests/arrays.rs
index 4d87728b..07e2cd30 100644
--- a/src/tests/arrays.rs
+++ b/src/tests/arrays.rs
@@ -1,5 +1,5 @@
 use engine::Engine;
-use fn_register::FnRegister;
+use fn_register::RegisterFn;
 
 #[test]
 fn test_arrays() {
diff --git a/src/tests/float.rs b/src/tests/float.rs
index 6030a5b2..573077ff 100644
--- a/src/tests/float.rs
+++ b/src/tests/float.rs
@@ -1,5 +1,5 @@
 use engine::Engine;
-use fn_register::FnRegister;
+use fn_register::RegisterFn;
 
 #[test]
 fn test_float() {
diff --git a/src/tests/get_set.rs b/src/tests/get_set.rs
index 46790e81..6315ad2c 100644
--- a/src/tests/get_set.rs
+++ b/src/tests/get_set.rs
@@ -1,5 +1,5 @@
 use engine::Engine;
-use fn_register::FnRegister;
+use fn_register::RegisterFn;
 
 #[test]
 fn test_get_set() {
@@ -86,9 +86,5 @@ fn test_big_get_set() {
 
     engine.register_fn("new_tp", TestParent::new);
 
-    if let Ok(result) = engine.eval::<i64>("let a = new_tp(); a.child.x = 500; a.child.x") {
-        assert_eq!(result, 500);
-    } else {
-        assert!(false);
-    }
+    assert_eq!(engine.eval::<i64>("let a = new_tp(); a.child.x = 500; a.child.x"), Ok(500));
 }
diff --git a/src/tests/method_call.rs b/src/tests/method_call.rs
index a2c36ed9..72ed3064 100644
--- a/src/tests/method_call.rs
+++ b/src/tests/method_call.rs
@@ -1,5 +1,5 @@
 use engine::Engine;
-use fn_register::FnRegister;
+use fn_register::RegisterFn;
 
 #[test]
 fn test_method_call() {
diff --git a/src/tests/mismatched_op.rs b/src/tests/mismatched_op.rs
index 381e2b39..a3e04999 100644
--- a/src/tests/mismatched_op.rs
+++ b/src/tests/mismatched_op.rs
@@ -4,8 +4,8 @@ use engine::{Engine, EvalAltResult};
 fn test_mismatched_op() {
     let mut engine = Engine::new();
 
-    match engine.eval::<i64>("60 + \"hello\"") {
-        Err(EvalAltResult::ErrorFunctionArgMismatch) => (),
-        _ => assert!(false),
-    }
+    assert_eq!(
+        engine.eval::<i64>("60 + \"hello\""),
+        Err(EvalAltResult::ErrorFunctionNotFound)
+    );
 }