Some halfwritten stuff

src/rukka_lang/mod.rs

@@ -18,19 +18,67 @@ impl ProgrammingLanguageInterface for Rukka {
 
   fn evaluate_in_repl(&mut self, input: &str, _eval_options: &EvalOptions) -> ReplOutput {
     let mut output = ReplOutput::default();
-    output.add_output(eval(input));
+    output.add_output(parse(input).and_then(|x| eval(x)).unwrap());
     output
   }
 }
 
-fn eval(input: &str) -> String {
-  let a = List { next: None };
-  let b = List { next: Some(&a) };
+fn eval(ast: Sexp) -> Result<String, String> {
+  Ok(format!("Everything is ()"))
+}
 
-  format!("Everything is () {:?}", b)
+enum Token {
+  LParen,
+  RParen,
+  Symbol(String)
+}
+
+fn tokenize(input: &str) -> Vec<Token> {
+  let mut iter = input.chars().peekable();
+  let mut tokens = Vec::new();
+  loop {
+    match iter.next() {
+      None => break,
+      Some('(') => tokens.push(LParen),
+      Some(')') => tokens.push(RParen),
+      Some(c) if c.is_whitespace() => continue,
+      Some(c) => {
+        let mut sym = String::new();
+        loop {
+          match iter.peek() {
+            None | Some('(') | Some(')') => break,
+            Some(c) if c.is_whitespace() => break,
+            Some(c) => sym.push_char(c),
+          }
+          iter.next();
+        }
+        tokens.push(Symbol(sym));
+      }
+    }
+  }
+  tokens
+}
+
+fn parse(input: &str) -> Result<Sexp, String> {
+  let _tokens = tokenize(input);
+  Ok(Sexp::Atom(AtomT::Number(1)))
+}
+
+#[derive(Debug)]
+enum Sexp {
+  Atom(AtomT),
+  List(Vec<Sexp>),
+}
+
+#[derive(Debug)]
+enum AtomT {
+  Symbol(String),
+  Number(u64),
 }
 
 #[derive(Debug)]
 struct List<'a> {
   next: Option<&'a List<'a>>,
+  data: usize
 }
+