differentiate floor and regular division

src/executor.rs

@@ -185,7 +185,7 @@ where
                         _ => Err(RuntimeError::NoOverloadForTypes("*".into(), args)),
                     }
                     Op::Div => match &args[..] {
-                        [Value::Int(x), Value::Int(y)] => Ok(Value::Int(x / y)),
+                        [Value::Int(x), Value::Int(y)] => Ok(Value::Float(*x as f64 / *y as f64)),
                         [Value::Float(x), Value::Int(y)] => Ok(Value::Float(x / *y as f64)),
                         [Value::Int(x), Value::Float(y)] => Ok(Value::Float(*x as f64 / y)),
                         [Value::Float(x), Value::Float(y)] => Ok(Value::Float(x / y)),
@@ -193,6 +193,15 @@ where
                         [x, Value::Nil] => Ok(x.clone()),
                         _ => Err(RuntimeError::NoOverloadForTypes("/".into(), args)),
                     }
+                    Op::FloorDiv => match &args[..] {
+                        [Value::Int(x), Value::Int(y)] => Ok(Value::Int(x / y)),
+                        [Value::Float(x), Value::Int(y)] => Ok(Value::Int(*x as i64 / y)),
+                        [Value::Int(x), Value::Float(y)] => Ok(Value::Int(x / *y as i64)),
+                        [Value::Float(x), Value::Float(y)] => Ok(Value::Int(*x as i64 / *y as i64)),
+                        [Value::Nil, x] => Ok(x.clone()),
+                        [x, Value::Nil] => Ok(x.clone()),
+                        _ => Err(RuntimeError::NoOverloadForTypes("//".into(), args)),
+                    }
                     Op::Exp => match &args[..] {
                         [Value::Int(x), Value::Int(y)] => Ok(Value::Float((*x as f64).powf(*y as f64))),
                         [Value::Float(x), Value::Int(y)] => Ok(Value::Float(x.powf(*y as f64))),

src/parser.rs

@@ -137,7 +137,8 @@ impl<'a, I: Iterator<Item = Result<Token, TokenizeError>>> Parser<'a, I> {
             (Op::Add, FunctionType(Box::new(Type::Any), vec![Type::Any, Type::Any])),
             (Op::Sub, FunctionType(Box::new(Type::Any), vec![Type::Any, Type::Any])),
             (Op::Mul, FunctionType(Box::new(Type::Any), vec![Type::Any, Type::Any])),
-            (Op::Div, FunctionType(Box::new(Type::Any), vec![Type::Any, Type::Any])),
+            (Op::Div, FunctionType(Box::new(Type::Float), vec![Type::Any, Type::Any])),
+            (Op::FloorDiv, FunctionType(Box::new(Type::Int), vec![Type::Any, Type::Any])),
             (Op::Exp, FunctionType(Box::new(Type::Any), vec![Type::Any, Type::Any])),
             (Op::Mod, FunctionType(Box::new(Type::Any), vec![Type::Any, Type::Any])),
             (Op::Id, FunctionType(Box::new(Type::Any), vec![Type::Any])),

src/tokenizer.rs

@@ -47,6 +47,7 @@ pub enum Op {
     Sub,
     Mul,
     Div,
+    FloorDiv,
     Exp,
     Equ,
     Mod,
@@ -180,6 +181,7 @@ impl<R: BufRead> Tokenizer<R> {
             ("-", Op::Sub),
             ("*", Op::Mul),
             ("/", Op::Div),
+            ("//", Op::FloorDiv),
             ("**", Op::Exp),
             ("%", Op::Mod),
             ("=", Op::Equ),