Finally have things printing to the screen

Nothing fancy yet. This commit adds a bunch of stuff (oops):

* compiling code
* VM with instructions
* remove eval.rs and just eval in the Machine struct itself
* squash most warnings now that we're using stuff here

And probably more. But that's all for now folks

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

src/syn/parser.rs

@@ -117,7 +117,7 @@ impl<'t> Parser<'t> {
 
     pub fn next_atom(&mut self) -> Result<SpAtom> {
         use Token::*;
-        let token = self.expect_any_token(&[Word, Float, Int, Str])?;
+        let token = self.expect_any_token(&[Assign, Word, Float, Int, Str, Bang])?;
         Ok(self.token_to_atom(token))
     }
 
@@ -126,10 +126,12 @@ impl<'t> Parser<'t> {
         let (span, token) = token.into_split();
         let text = span.text_at(self.lexer.text());
         let atom = match token {
+            Token::Assign => Atom::Assign(text[1..].to_string()),
             Token::Word => Atom::Word(text.to_string()),
             Token::Float => Atom::Float(text.parse().unwrap()),
             Token::Int => Atom::Int(text.parse().unwrap()),
             Token::Str => Atom::Str(unescape_string(text)),
+            Token::Bang => Atom::Apply,
             _ => panic!("invalid token specified for token_to_atom, it should be an atom"),
         };
         SpAtom::new(span, atom)