diff --git a/ablescript/src/interpret.rs b/ablescript/src/interpret.rs
index d1eb20c..a2239e2 100644
--- a/ablescript/src/interpret.rs
+++ b/ablescript/src/interpret.rs
@@ -273,7 +273,7 @@ impl ExecEnv {
                 let mut value = 0;
                 for _ in 0..READ_BITS {
                     value <<= 1;
-                    value += self.get_bit()? as i32;
+                    value += self.get_bit()? as isize;
                 }
 
                 self.assign(assignable, Value::Int(value))?;
@@ -644,7 +644,7 @@ mod tests {
             env.eval_expr(&Expr {
                 kind: ExprKind::BinOp {
                     lhs: Box::new(Expr {
-                        kind: ExprKind::Literal(Value::Int(i32::MAX)),
+                        kind: ExprKind::Literal(Value::Int(isize::MAX)),
                         span: 1..1,
                     }),
                     rhs: Box::new(Expr {
diff --git a/ablescript/src/variables.rs b/ablescript/src/variables.rs
index cb5a9f6..198361c 100644
--- a/ablescript/src/variables.rs
+++ b/ablescript/src/variables.rs
@@ -176,11 +176,13 @@ impl Value {
                 Functio::Bf {
                     instructions,
                     tape_len,
-                } => instructions.into_iter().map(|x| x as isize).sum::<isize>() * tape_len as isize,
+                } => {
+                    instructions.into_iter().map(|x| x as isize).sum::<isize>() * tape_len as isize
+                }
                 Functio::Able { params, body } => {
                     params
                         .into_iter()
-                        .map(|x| x.bytes().map(|x| x as i32).sum::<i32>())
+                        .map(|x| x.bytes().map(|x| x as isize).sum::<isize>())
                         .sum::<isize>()
                         + body.len() as isize
                 }
@@ -261,14 +263,14 @@ impl Value {
                 )
                 .into_abool(),
                 Functio::Able { params, body } => {
-                    let str_to_i32 =
-                        |x: String| -> i32 { x.as_bytes().into_iter().map(|x| *x as i32).sum() };
+                    let str_to_isize =
+                        |x: String| -> isize { x.as_bytes().into_iter().map(|x| *x as isize).sum() };
 
-                    let params: i32 = params.into_iter().map(str_to_i32).sum();
-                    let body: i32 = body
+                    let params: isize = params.into_iter().map(str_to_isize).sum();
+                    let body: isize = body
                         .into_iter()
                         .map(|x| format!("{:?}", x))
-                        .map(str_to_i32)
+                        .map(str_to_isize)
                         .sum();
 
                     Value::Int((params + body) % 3 - 1).into_abool()
@@ -373,7 +375,7 @@ impl Value {
                 .enumerate()
                 .map(|(i, x)| {
                     (
-                        Value::Int(i as i32 + 1),
+                        Value::Int(i as isize + 1),
                         Rc::new(RefCell::new(Value::Str(x.to_string()))),
                     )
                 })
@@ -388,7 +390,7 @@ impl Value {
                         .enumerate()
                         .map(|(i, x)| {
                             (
-                                Value::Int(i as i32 + 1),
+                                Value::Int(i as isize + 1),
                                 Rc::new(RefCell::new(Value::Str(x))),
                             )
                         })
@@ -399,7 +401,7 @@ impl Value {
                         .enumerate()
                         .map(|(i, x)| {
                             (
-                                Value::Int(i as i32 + 1),
+                                Value::Int(i as isize + 1),
                                 Rc::new(RefCell::new(Value::Str(format!("{:?}", x)))),
                             )
                         })
@@ -427,7 +429,7 @@ impl Value {
                         .enumerate()
                         .map(|(i, x)| {
                             (
-                                Value::Int(i as i32 + 1),
+                                Value::Int(i as isize + 1),
                                 Rc::new(RefCell::new(
                                     char::from_u32(x as u32)
                                         .map(|x| Value::Str(x.to_string()))
@@ -480,7 +482,7 @@ impl Value {
     }
 
     /// Get a lenght of a value
-    pub fn len(&self) -> i32 {
+    pub fn len(&self) -> isize {
         match self {
             Value::Nul => 0,
             Value::Str(s) => s.len() as _,
@@ -508,9 +510,7 @@ impl Value {
                     tape_len,
                 } => (instructions.len() + tape_len) as _,
                 Functio::Able { params, body } => (params.len() + format!("{:?}", body).len()) as _,
-                Functio::Builtin(b) => {
-                    (std::mem::size_of_val(b.function.as_ref()) + b.arity) as i32
-                }
+                Functio::Builtin(b) => (std::mem::size_of_val(b.function.as_ref()) + b.arity) as _,
                 Functio::Chain { functios, kind } => {
                     let (lhs, rhs) = *functios.clone();
                     match kind {
@@ -746,7 +746,7 @@ impl ops::Div for Value {
                     .enumerate()
                     .map(|(i, x)| {
                         (
-                            Value::Int(i as i32 + 1),
+                            Value::Int(i as isize + 1),
                             Rc::new(RefCell::new(Value::Str(x.to_owned()))),
                         )
                     })
@@ -815,7 +815,7 @@ impl ops::Div for Value {
                         .enumerate()
                         .map(|(k, v)| {
                             (
-                                Value::Int(k as i32 + 1),
+                                Value::Int(k as isize + 1),
                                 Rc::new(RefCell::new(Value::Cart(v.iter().cloned().collect()))),
                             )
                         })