Starting out with minimal BNF

Just to test this idea, I'm going to start out with this simplified
BNF of just literals

src/schala_lang/autoparser.rs

@@ -9,6 +9,18 @@ struct AutoParser {
   tokens: Vec<Token>,
 }
 
+/* BNF
+ * all terminals in this BNF refer to TokenType values
+ 
+ literal := Kw::True | Kw::False | StrLiteral | number_literal
+ number_literal := int_literal | float_literal
+ float_literal := digits float_continued
+ float_continued := ε | Period digits
+ int_literal := HexLiteral | nonhex_int
+ nonhex_int := BinNumberSigil+ digits 
+ digits := (DigitGroup Underscore)+
+ */
+
 impl AutoParser {
   fn new(tokens: Vec<Token>) -> AutoParser {
     AutoParser { tokens: tokens.into_iter().rev().collect() }