Add parser and AST, remove some stuff from lexer

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/syn/token.rs

@@ -3,6 +3,8 @@ use std::fmt::{Display, Formatter, self};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum TokenKind {
+    KwReturn,
+
     Ident,
     Num,
     Str,
@@ -18,14 +20,18 @@ pub enum TokenKind {
 
     Eq,
     Arrow,
-
-    KwReturn,
+    Plus,
+    Minus,
+    Splat,
+    FSlash,
 }
 
 impl Display for TokenKind {
     fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
         use TokenKind::*;
         let s = match self {
+            KwReturn => "return keyword",
+
             Ident => "identifier",
             Num => "number",
             Str => "string",
@@ -41,8 +47,10 @@ impl Display for TokenKind {
 
             Eq => "equals",
             Arrow => "arrow",
-
-            KwReturn => "return keyword",
+            Plus => "plus",
+            Minus => "minus",
+            Splat => "splat (or times)",
+            FSlash => "fslash (or divide)",
         };
         Display::fmt(s, fmt)
     }