Lex dots: .

src/lexer/char.rs

@@ -8,6 +8,7 @@ pub trait Lexable {
     fn is_left_paren(&self) -> bool;
     fn is_right_paren(&self) -> bool;
     fn is_hash(&self) -> bool;
+    fn is_dot(&self) -> bool;
     fn is_string_quote(&self) -> bool;
     fn is_newline(&self) -> bool;
     fn is_eof(&self) -> bool;
@@ -32,6 +33,10 @@ impl Lexable for char {
         *self == '#'
     }
 
+    fn is_dot(&self) -> bool {
+        *self == '.'
+    }
+    
     fn is_string_quote(&self) -> bool {
         *self == '"'
     }

src/lexer/mod.rs

@@ -89,6 +89,9 @@ impl Lexer {
         else if c.is_right_paren() {
             *token = Some(Token::RightParen(c.to_string()));
         }
+        else if c.is_dot() {
+            *token = Some(Token::Dot);
+        }
         else if c.is_hash() {
             self.state = State::Hash;
             self.advance();
@@ -207,6 +210,11 @@ mod tests {
         check_single_token(")", Token::RightParen(String::from(")")));
     }
 
+    #[test]
+    fn lexer_finds_dots() {
+        check_single_token(".", Token::Dot);
+    }
+
     #[test]
     fn lexer_finds_identifiers() {
         check_single_token("abc", Token::Identifier(String::from("abc")));

src/lexer/token.rs

@@ -7,6 +7,7 @@
 pub enum Token {
     LeftParen(String),
     RightParen(String),
+    Dot,
     Identifier(String),
     Boolean(bool),
     String(String),