Fix io.read_line function

dust-lang/src/abstract_tree/assignment.rs

@@ -100,6 +100,12 @@ impl AbstractNode for Assignment {
 
         let statement_type = self.statement.expected_type(context)?;
 
+        if statement_type.is_none() {
+            return Err(ValidationError::CannotAssignToNone(
+                self.statement.last_evaluated_statement().position(),
+            ));
+        }
+
         if let (Some(expected_type_constructor), Some(actual_type)) =
             (&self.constructor, statement_type)
         {

dust-lang/src/abstract_tree/built_in_function.rs

@@ -1,8 +1,4 @@
-use std::{
+use std::{array, fs::read_to_string, io::stdin};
-    array,
-    fs::read_to_string,
-    io::{self, stdin},
-};
 
 use serde::{Deserialize, Serialize};
 use serde_json::from_str;
@@ -308,9 +304,13 @@ impl FunctionLogic for ReadLine {
     }
 
     fn call(self, _: &Context, _: bool) -> Result<Option<Evaluation>, RuntimeError> {
-        let user_input = io::read_to_string(stdin())?;
+        let mut user_input = String::new();
 
-        Ok(Some(Evaluation::Return(Value::string(user_input))))
+        stdin().read_line(&mut user_input)?;
+
+        Ok(Some(Evaluation::Return(Value::string(
+            user_input.trim_end_matches('\n'),
+        ))))
     }
 }
 

dust-lang/src/parser/mod.rs

@@ -549,7 +549,7 @@ pub fn parser<'src>(
                 ),
                 infix(
                     left(1),
-                    just(Token::Symbol(Symbol::Slash)),
+                    just(Token::Symbol(Symbol::Percent)),
                     |left, _, right, span| {
                         Expression::Math(Box::new(Math::Modulo(left, right)).with_position(span))
                     },