Create a new list implementation based on vectors

src/ast.rs

@@ -25,14 +25,22 @@ pub enum Expr {
     Num(Number),
     Comment,
     Error(String),
-    List(Box<collections::List>),
+    Cons(Box<collections::List>),
     Nil,
     NoMatch,
 }
 
 impl Expr {
-    pub fn make_list(first: Expr, rest: Expr) -> Expr {
-        Expr::List(Box::new(collections::List::new(first, rest)))
+    pub fn make_list(elements: &[Expr]) -> Expr {
+        Expr::Cons(Box::new(collections::List::new(elements)))
+    }
+
+    pub fn list_to_cons(l: collections::List) -> Expr {
+        Expr::Cons(Box::new(l))
+    }
+
+    pub fn make_empty_list() -> collections::List {
+        collections::List::new_empty()
     }
 
     pub fn make_symbol(v: String) -> Expr {

src/builtins/def.rs

@@ -14,26 +14,27 @@
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+use crate::ast::Expr;
 use crate::compiler::Compiler;
 use crate::types::collections::core::{first, rest};
 use crate::types::{ExprResult, List};
 
 pub fn def<'a>(compiler: &'a Compiler, args: &'a List) -> ExprResult<'a> {
     // TODO: We need to support docstrings for def
-    if args.length != 3 {
-        // TODO: Raise a meaningful error by including the location
-        panic!(format!(
-            "`def` expects 2 parameters, '{}' given.",
-            args.length
-        ));
-    }
+    // if args.length != 3 {
+    //     // TODO: Raise a meaningful error by including the location
+    //     panic!(format!(
+    //         "`def` expects 2 parameters, '{}' given.",
+    //         args.length
+    //     ));
+    // }
 
-    //let def_ = &args.first;1
-    let name = first(rest(args));
-    //let value = first(rest(rest(args)));
+    // //let def_ = &args.first;1
+    // let name = first(rest(args));
+    // //let value = first(rest(rest(args)));
 
-    println!("<<<< {:?}", name);
-    // TODO: make sure that `def_` is a symbol and its name is "def"
+    // println!("<<<< {:?}", name);
+    // // TODO: make sure that `def_` is a symbol and its name is "def"
 
     Err("Is not completed".to_string())
 }

src/reader.rs

@@ -91,10 +91,9 @@ impl ExprReader {
 
     fn read_quoted_expr<T: Read>(&mut self, reader: &mut BufReader<T>) -> ReadResult {
         let rest = self.read_expr(reader)?;
-        Ok(Expr::make_list(
-            Expr::make_symbol("quote".to_string()),
-            rest,
-        ))
+        let elements = vec![Expr::make_symbol("quote".to_string()), rest];
+
+        Ok(Expr::make_list(&elements))
     }
 
     fn read_unquoted_expr<T: Read>(&mut self, reader: &mut BufReader<T>) -> ReadResult {
@@ -103,50 +102,47 @@ impl ExprReader {
                 // Move forward in the buffer since we peeked it
                 let _ = self.get_char(reader, true);
                 let rest = self.read_expr(reader)?;
-                Ok(Expr::make_list(
-                    Expr::make_symbol("unquote-splicing".to_string()),
-                    rest,
-                ))
+                let elements = vec![Expr::make_symbol("unquote-splicing".to_string()), rest];
+                Ok(Expr::make_list(&elements))
             }
             _ => {
                 let rest = self.read_expr(reader)?;
-                Ok(Expr::make_list(
-                    Expr::make_symbol("unquote".to_string()),
-                    rest,
-                ))
+                let elements = vec![Expr::make_symbol("unquote".to_string()), rest];
+                Ok(Expr::make_list(&elements))
             }
         }
     }
 
     fn read_quasiquoted_expr<T: Read>(&mut self, reader: &mut BufReader<T>) -> ReadResult {
         let rest = self.read_expr(reader)?;
-        Ok(Expr::make_list(
-            Expr::make_symbol("quasiquote".to_string()),
-            rest,
-        ))
+        let elements = vec![Expr::make_symbol("quasiquote".to_string()), rest];
+        Ok(Expr::make_list(&elements))
     }
 
     // TODO: We might want to replace Cons with an actual List struct
     fn read_list<T: Read>(&mut self, reader: &mut BufReader<T>) -> ReadResult {
-        let first = match self.read_expr(reader) {
-            Ok(value) => value,
+        let mut result = Expr::make_empty_list();
+
+        match self.read_expr(reader) {
+            Ok(value) => result.push(value),
             Err(e) => match self.get_char(reader, true) {
                 // is it an empty list ?
                 // TODO: we might want to return an actual empty list here
-                Some(')') => return Ok(Expr::Nil),
+                Some(')') => return Ok(Expr::list_to_cons(result)),
                 _ => return Err(e),
             },
         };
 
-        let rest = match self.get_char(reader, true) {
-            Some(e) => {
-                self.unget_char(e);
-                self.read_list(reader)?
-            }
-            None => return Err("Unexpected EOF while parsing a list.".to_string()),
-        };
-
-        Ok(Expr::make_list(first, rest))
+        loop {
+            let next = match self.get_char(reader, true) {
+                Some(')') => return Ok(Expr::list_to_cons(result)),
+                Some(e) => {
+                    self.unget_char(e);
+                    result.push(self.read_expr(reader)?)
+                }
+                None => return Err("Unexpected EOF while parsing a list.".to_string()),
+            };
+        }
     }
 
     fn is_valid_for_identifier(&self, c: char) -> bool {

src/types/collections/list.rs

@@ -22,34 +22,27 @@ use crate::types::core::{ExprResult, Expression};
 
 #[derive(Debug, Eq, PartialEq, Clone)]
 pub struct List {
-    pub car: Expr,
-    pub cdr: Expr,
-    pub length: u64,
+    elements: Vec<Expr>,
 }
-//pub enum List<T> { Nil, Cons(T, Box<List<T>>) }
 
 impl List {
-    pub fn new(first: Expr, rest: Expr) -> List {
-        // The order of field definition is important here.
-        // If we move the `length` after `rest` we're going
-        // to break the ownership rule of rust because `rest: rest`
-        // is going to move it to the new list and we can not
-        // borrow it afterward.
+    pub fn new_empty() -> List {
+        List { elements: vec![] }
+    }
+
+    pub fn new(elems: &[Expr]) -> List {
         List {
-            length: match &rest {
-                Expr::Cons(v) => v.length + 1,
-                _ => {
-                    if let Expr::Nil = first {
-                        0
-                    } else {
-                        1
-                    }
-                }
-            },
-            car: first,
-            cdr: rest,
+            elements: elems.to_vec(),
         }
     }
+
+    pub fn push(&mut self, elem: Expr) {
+        self.elements.push(elem)
+    }
+
+    // pub fn new(first: T, rest: List<T>) -> List<T> {
+    //     List::Cons(first, Box::new(rest))
+    // }
 }
 
 impl Expression for List {
@@ -59,21 +52,21 @@ impl Expression for List {
         //     Expr::Sym(s) => def(compiler, self),
         //     _ => ,
         // }
-        def(compiler, self);
+        //def(compiler, self);
         Err("Not implemented on list".to_string())
     }
 }
 
-impl Seq<Expr> for List {
-    fn first<'a>(&'a self) -> &'a Expr {
-        &self.car
-    }
+// impl Seq<Expr> for List<T> {
+//     fn first<'a>(&'a self) -> &'a Expr {
+//         &self.car
+//     }
 
-    fn rest<'a>(&'a self) -> Option<&'a List> {
-        match &self.cdr {
-            Expr::Nil => None,
-            Expr::Cons(v) => Some(v),
-            _ => panic!("'rest' should not match anything else!"),
-        }
-    }
-}
+//     fn rest<'a>(&'a self) -> Option<&'a List> {
+//         match &self.cdr {
+//             Expr::Nil => None,
+//             Expr::Cons(v) => Some(v),
+//             _ => panic!("'rest' should not match anything else!"),
+//         }
+//     }
+// }