Introduced index notation

src/schala_lang/eval.rs

@@ -310,6 +310,9 @@ impl<'a> Evaluator<'a> {
                     }
                 }
             }
+            Index(box expr, box index_expr) => {
+                (Null, None)
+            }
         }
     }
 

src/schala_lang/parser.rs

@@ -72,6 +72,7 @@ pub enum Expression {
     Lambda(Function),
     Block(VecDeque<Expression>),
     While(Box<Expression>, Vec<Expression>),
+    Index(Box<Expression>, Box<Expression>),
 }
 
 #[derive(Clone, Debug)]
@@ -402,7 +403,10 @@ impl Parser {
                 }
             },
             Some(LSquareBracket) => {
-                unimplemented!()
+                expect!(self, LSquareBracket);
+                let index_expr = self.expression()?;
+                expect!(self, RSquareBracket);
+                Index(Box::new(expr), Box::new(index_expr))
             },
             _ => {
                 expr

src/schala_lang/tokenizer.rs

@@ -120,7 +120,7 @@ fn tokenize_identifier(c: char, iter: &mut Peekable<Chars>) -> Result<Token, Tok
     fn ends_identifier(c: &char) -> bool {
         let c = *c;
         char::is_whitespace(c) || is_digit(&c) || c == ';' || c == '(' || c == ')' ||
-        c == ',' || c == '.' || c == ',' || c == ':'
+        c == ',' || c == '.' || c == ',' || c == ':' || c == '[' || c == ']'
     }
 
     use self::Token::*;