add quote special form

src/main.rs

@@ -610,6 +610,7 @@ pub fn rw(rule: &Rule, sexp: &Sexp) -> Sexp {
 pub fn simp(rules: &[Rule], mut expr: Sexp, step_limit: usize, complexity_limit: usize) -> Sexp {
     for _ in 0..step_limit {
         expr = expr
+            .apply_special_form::<Quote>()
             .apply_special_form::<Genslop>()
             .apply_special_form::<LambdaLike>()
             .apply_special_form::<App>()
@@ -867,6 +868,42 @@ impl<'src> SpecialForm<'src> for LambdaLike<'src> {
     }
 }
 
+static QUOTE: Lazy<Symbol> = Lazy::new(|| TABLE.lock().unwrap().intern("quote").unwrap());
+static CONS: Lazy<Symbol> = Lazy::new(|| TABLE.lock().unwrap().intern("cons").unwrap());
+
+// sbcl has quote take one arg....
+#[derive(Debug, Clone)]
+struct Quote<'src>(&'src Sexp);
+
+impl<'src> SpecialForm<'src> for Quote<'src> {
+    fn from_sexp(sexp: &'src Sexp) -> Option<Self> {
+        match sexp {
+            Sexp::Atom(_) => None,
+            Sexp::List(xs) => match &xs[..] {
+                [Sexp::Atom(quote), expr] if *quote == *QUOTE => Some(Self(expr)),
+                _ => None,
+            },
+        }
+    }
+
+    fn eval(self) -> Sexp {
+        let Self(expr) = self;
+
+        match expr {
+            Sexp::Atom(at) => Sexp::Atom(*at),
+            Sexp::List(xs) => consify(xs),
+        }
+    }
+}
+
+fn consify(xs: &[Sexp]) -> Sexp {
+    if xs.is_empty() {
+        Sexp::nil()
+    } else {
+        Sexp::List(vec![Sexp::Atom(*CONS), consify(&xs[1..])])
+    }
+}
+
 pub fn make_rule(sexp: &Sexp) -> Option<Rule> {
     match sexp {
         Sexp::List(xs) => match &xs[..] {