diff --git a/src/compiler/compile.rs b/src/compiler/compile.rs
index 828a291..e5a20bc 100644
--- a/src/compiler/compile.rs
+++ b/src/compiler/compile.rs
@@ -30,7 +30,7 @@ pub fn compile(program: String) -> Result<(), Box<dyn Error>> {
         .first_element_child()
         .ok_or(InvalidProgram)?
         .children()
-        .find(|node| util::tag_name(&node) == "main")
+        .find(|node| util::tag_name(node) == "main")
         .ok_or(MissingChild("program", "main"))?;
     let main_ast = Instruction::from_children(main)?;
 
diff --git a/src/instruction.rs b/src/instruction.rs
index 42d5b30..43b0fdd 100644
--- a/src/instruction.rs
+++ b/src/instruction.rs
@@ -46,7 +46,7 @@ impl Instruction {
         Ok(match util::tag_name(&node).as_str() {
             "value" => Instruction::Value(
                 node.attribute("variable")
-                    .and_then(|a| Some(String::from(a)))
+                    .map(String::from)
                     .ok_or(MissingAttribute("value", "variable"))?,
             ),
             "assign" => Instruction::Assign(
diff --git a/src/interpreter/run.rs b/src/interpreter/run.rs
index f04fe58..15ae322 100644
--- a/src/interpreter/run.rs
+++ b/src/interpreter/run.rs
@@ -234,7 +234,7 @@ impl RunUtil for Instruction {
 pub trait Run {
     fn run(&self, ctx: &mut Context, globals: &Context) -> Result<Option<Value>, Box<dyn Error>>;
     fn run_all(
-        ins: &Vec<Instruction>,
+        ins: &[Instruction],
         ctx: &mut Context,
         globals: &Context,
     ) -> Result<Option<Vec<Value>>, Box<dyn Error>>;
@@ -242,7 +242,7 @@ pub trait Run {
 
 impl Run for Instruction {
     fn run_all(
-        ins: &Vec<Instruction>,
+        ins: &[Instruction],
         ctx: &mut Context,
         globals: &Context,
     ) -> Result<Option<Vec<Value>>, Box<dyn Error>> {
@@ -250,11 +250,11 @@ impl Run for Instruction {
     }
 
     fn run(&self, ctx: &mut Context, globals: &Context) -> Result<Option<Value>, Box<dyn Error>> {
-        Ok(if let None = ctx.value(&String::from("__return")) {
+        Ok(if ctx.value(&String::from("__return")).is_none() {
             match self {
                 Instruction::Value(key) => {
                     Some(match ctx.value(key).ok_or(UnknownVariable(key.clone()))? {
-                        Value::Array(vecrc) => Value::Array(Rc::clone(&vecrc)),
+                        Value::Array(vecrc) => Value::Array(Rc::clone(vecrc)),
                         val => val.clone(),
                     })
                 }
@@ -388,7 +388,7 @@ impl Run for Instruction {
                     let vals: Vec<Value> =
                         Instruction::run_all(args, ctx, globals)?.ok_or(InvalidValue("call"))?;
                     let fct_val = ctx
-                        .value(&fct_name)
+                        .value(fct_name)
                         .ok_or(UnknownVariable(fct_name.clone()))?;
                     if let Value::Function(f) = fct_val {
                         let mut local = ctx.clone();
@@ -511,7 +511,7 @@ pub fn run(program: String) -> Result<(), Box<dyn Error>> {
         .first_element_child()
         .ok_or(InvalidProgram)?
         .children()
-        .find(|node| util::tag_name(&node) == "main")
+        .find(|node| util::tag_name(node) == "main")
         .ok_or(MissingChild("program", "main"))?;
     let main_ast = Instruction::from_children(main)?;
 
@@ -519,7 +519,7 @@ pub fn run(program: String) -> Result<(), Box<dyn Error>> {
         .first_element_child()
         .ok_or(InvalidProgram)?
         .children()
-        .filter(|node| node.tag_name().name() == String::from("function"));
+        .filter(|node| node.tag_name().name() == "function");
 
     for fun in functions {
         ctx.assign(
diff --git a/src/interpreter/stl.rs b/src/interpreter/stl.rs
index a5887e5..439b49b 100644
--- a/src/interpreter/stl.rs
+++ b/src/interpreter/stl.rs
@@ -62,7 +62,7 @@ fn print_line(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
 }
 
 fn input(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
-    if vals.len() == 0 {
+    if vals.is_empty() {
         let mut line = String::new();
         stdin().read_line(&mut line)?;
         line.pop();
@@ -181,7 +181,7 @@ fn array_length(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
 fn to_ascii(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
     if vals.len() == 1 {
         if let Value::Integer(i) = &vals[0] {
-            if &0 <= i && i <= &255 {
+            if (0..=255).contains(i) {
                 Ok(Some(Value::String(String::from_utf8(vec![*i as u8])?)))
             } else {
                 Err(InvalidArgument("to-ascii", "integer").into())
@@ -211,12 +211,9 @@ fn from_ascii(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
 }
 
 fn get_args(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
-    if vals.len() == 0 {
+    if vals.is_empty() {
         Ok(Some(Value::Array(Rc::new(RefCell::new(
-            std::env::args()
-                .skip(1)
-                .map(|arg| Value::String(arg))
-                .collect(),
+            std::env::args().skip(1).map(Value::String).collect(),
         )))))
     } else {
         Err(BadArgumentCount("get-args", vals.len(), 0).into())
@@ -233,7 +230,7 @@ fn write_file(vals: Vec<Value>) -> Result<Option<Value>, Box<dyn Error>> {
                     .append(Value::to_bool(&vals[2]))
                     .open(path)
                 {
-                    if let Ok(_) = write!(file, "{}", contents) {
+                    if write!(file, "{}", contents).is_ok() {
                         Ok(None)
                     } else {
                         Err(InaccessibleFile(path.clone()).into())
diff --git a/src/interpreter/value.rs b/src/interpreter/value.rs
index 5939ba6..fdd9c6c 100644
--- a/src/interpreter/value.rs
+++ b/src/interpreter/value.rs
@@ -27,7 +27,7 @@ impl Function {
         }
         self.args
             .iter()
-            .zip(args.into_iter())
+            .zip(args)
             .for_each(|(p, a)| ctx.assign(p.clone(), a));
         for i in self.ins.iter() {
             i.run(ctx, globals)?;
@@ -37,20 +37,22 @@ impl Function {
 
     pub fn from(fun: &Node<'_, '_>) -> Result<Function, Box<dyn Error>> {
         Ok(Function {
-            args: util::find_node(&fun, "arguments")
+            args: util::find_node(fun, "arguments")
                 .ok_or(MissingChild("call", "arguments"))?
                 .children()
                 .filter(Node::is_element)
-                .map(|n| n.attribute("name").and_then(|s| Some(String::from(s))))
+                .map(|n| n.attribute("name").map(String::from))
                 .collect::<Option<Vec<String>>>()
                 .ok_or(Unnamed("argument"))?,
             ins: Instruction::from_children(
-                util::find_node(&fun, "body").ok_or(MissingChild("call", "body"))?,
+                util::find_node(fun, "body").ok_or(MissingChild("call", "body"))?,
             )?,
         })
     }
 }
 
+type StdFn = fn(Vec<Value>) -> Result<Option<Value>, Box<dyn Error>>;
+
 #[derive(Clone, Debug)]
 pub enum Value {
     Integer(i64),
@@ -58,7 +60,7 @@ pub enum Value {
     String(String),
     Array(Rc<RefCell<Vec<Value>>>),
     Function(Function),
-    StdFunction(fn(Vec<Value>) -> Result<Option<Value>, Box<dyn Error>>),
+    StdFunction(StdFn),
 }
 
 impl Value {
@@ -66,7 +68,7 @@ impl Value {
         match self {
             Value::Integer(i) => *i != 0,
             Value::Real(f) => *f != 0.0,
-            Value::String(s) => s.len() != 0,
+            Value::String(s) => !s.is_empty(),
             Value::Array(v) => v.borrow().len() != 0,
             _ => true,
         }