big temp status

Signed-off-by: Ava Hahn <ava@aidanis.online>

src/control.rs

@@ -0,0 +1,40 @@
+/* relish: versatile lisp shell
+ * Copyright (C) 2021 Aidan Hahn
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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::append::get_append;
+use crate::func::{func_declare, FTable, Ast};
+use crate::segment::Ctr;
+use crate::str::{get_concat, get_echo};
+use crate::vars::{get_export, VTable};
+use std::cell::RefCell;
+use std::rc::Rc;
+
+pub fn get_if() -> Function {
+    return Function {
+        name: String::from("if"),
+        loose_syms: false,
+        eval_lazy: true,
+        args: Args::Lazy(-1),
+        function: Operation::Internal(
+            Box::new(|args: Ast, vars: Rc<RefCell<VTable>>, funcs: Rc<RefCell<FTable>>| -> Ctr {
+                // Either 2 long or 3 long.
+                // arg 1 must eval to a bool
+                // then eval arg 2 or 3
+            })
+        ),
+    };
+}

src/lex.rs

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-use crate::segment::{list_append, new_ast, Ast, Ctr};
+use crate::segment::{list_append, Ctr, Seg};
 
 const UNMATCHED_STR_DELIM: &str = "Unmatched string delimiter in input";
 const UNMATCHED_LIST_DELIM: &str = "Unmatched list delimiter in input";
@@ -23,7 +23,7 @@ const UNMATCHED_LIST_DELIM: &str = "Unmatched list delimiter in input";
 /* takes a line of user input
  * returns an unsimplified tree of tokens.
  */
-pub fn lex(document: String) -> Result<Ast, String> {
+pub fn lex<'a>(document: String) -> Result<Box<Seg<'a>>, String> {
     if !document.is_ascii() {
         return Err("document may only contain ascii characters".to_string());
     }
@@ -42,7 +42,7 @@ pub fn lex(document: String) -> Result<Ast, String> {
  * Returns Ok(Rc<Seg>) if lexing passes
  * Returns Err(String) if an error occurs
  */
-fn process(document: String) -> Result<Ast, String> {
+fn process<'a>(document: &'a String) -> Result<Box<Seg<'a>>, String> {
     let doc_len = document.len();
 
     if doc_len == 0 {
@@ -120,7 +120,7 @@ fn process(document: String) -> Result<Ast, String> {
                         return Err("list started in middle of another token".to_string());
                     }
 
-                    ref_stack.push(new_ast(Ctr::None, Ctr::None));
+                    ref_stack.push(Box::new(Seg::new()));
 
                     delim_stack.push(')');
                 }
@@ -152,13 +152,12 @@ fn process(document: String) -> Result<Ast, String> {
                 return Err("Empty token".to_string());
             }
 
-            let mut current_seg_ref = ref_stack.pop().unwrap();
+            let mut current_seg = ref_stack.pop();
             let mut obj;
             if is_str {
                 obj = Ctr::String(token);
                 is_str = false;
                 token = String::new();
-                list_append(current_seg_ref.clone(), obj);
             } else if token.len() > 0 {
                 if token == "true" {
                     obj = Ctr::Bool(true);
@@ -175,22 +174,23 @@ fn process(document: String) -> Result<Ast, String> {
                 }
 
                 token = String::new();
-                list_append(current_seg_ref.clone(), obj);
             }
 
+            list_append(current_seg, obj);
+
             if alloc_list {
                 // return if we have finished the document
                 if ref_stack.len() == 0 {
-                    return Ok(current_seg_ref);
+                    return Ok(current_seg);
                 }
 
                 // shortening this will lead to naught but pain
-                obj = Ctr::Seg(current_seg_ref.clone());
-                current_seg_ref = ref_stack.pop().unwrap();
-                list_append(current_seg_ref.clone(), obj);
+                obj = Ctr::Seg(current_seg.into_raw());
+                current_seg = ref_stack.pop();
+                list_append(current_seg, obj);
             }
 
-            ref_stack.push(current_seg_ref);
+            ref_stack.push(current_seg);
         }
     }
 

src/lib.rs

@@ -15,6 +15,8 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#![feature(derive_default_enum)]
+
 mod append;
 mod config;
 mod eval;
@@ -31,7 +33,7 @@ pub mod ast {
         func_call, func_declare, Args, ExternalOperation, FTable, Function, Operation,
     };
     pub use crate::lex::lex;
-    pub use crate::segment::{ast_to_string, new_ast, Ast, Ctr, Seg, Type};
+    pub use crate::segment::{Ctr, Seg, Type};
     pub use crate::vars::{define, VTable};
 }
 

src/segment.rs

@@ -14,22 +14,19 @@
  * 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 std::fmt;
 
-use std::cell::RefCell;
-use std::rc::Rc;
-
-// Recursive data type for a tree of Segments
-pub type Ast = Rc<RefCell<Seg>>;
 
 // Container
-#[derive(Clone, Debug)]
-pub enum Ctr {
+#[derive(Debug, Clone, Default)]
+pub enum Ctr <'a> {
     Symbol(String),
     String(String),
     Integer(i128),
     Float(f64),
     Bool(bool),
-    Seg(Ast),
+    Seg(Seg<'a>),
+    #[default]
     None,
 }
 
@@ -48,23 +45,21 @@ pub enum Type {
 /* Segment
  * Holds two Containers.
  * Basic building block for more complex data structures.
- * I was going to call it Cell and then I learned about
- * how important RefCells were in Rust
  */
-#[derive(Clone, Debug)]
-pub struct Seg {
+#[derive(Clone, Debug, Default)]
+pub struct Seg <'a> {
     /* "Contents of Address Register"
      *  Historical way of referring to the first value in a cell.
      */
-    pub car: Ctr,
+    pub car: &mut Ctr<'a>,
 
     /* "Contents of Decrement Register"
      *  Historical way of referring to the second value in a cell.
      */
-    pub cdr: Ctr,
+    pub cdr: &mut Ctr<'a>,
 }
 
-impl Ctr {
+impl Ctr<'_> {
     pub fn to_type(&self) -> Type {
         match self {
             Ctr::Symbol(_s) => Type::Symbol,
@@ -76,10 +71,65 @@ impl Ctr {
             Ctr::None => Type::None,
         }
     }
+
+}
+
+fn seg_to_string(s: &Seg, parens: bool) -> String {
+    let mut string = String::new();
+    match s.car {
+        Ctr::None => string.push_str("<nil>"),
+        _ => string.push_str(s.car),
+    }
+    string.push(' ');
+    match s.cdr {
+        Ctr::Seg(inner) => string.push_str(seg_to_string(inner, false)),
+        Ctr::None => {},
+        _ => string.push_str(s.cdr),
+    }
+
+    if parens {
+        String::from("(" + string + ")")
+    }
+}
+
+impl fmt::Display for Ctr <'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Ctr::Symbol(s) => write!(f, "{}", s),
+            Ctr::String(s) => write!(f, "\'{}\'", s),
+            Ctr::Integer(s) => write!(f, "{}", s),
+            Ctr::Float(s) => write!(f, "{}", s),
+            Ctr::Bool(s) => {
+                if s {
+                    write!(f, "T")
+                } else {
+                    write!(f, "F")
+                }
+            },
+            Ctr::Seg(s) => write!(f, "{}", s),
+            Ctr::None => Ok(),
+        }
+    }
+}
+
+impl fmt::Display for Seg<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", seg_to_string(self, true))
+    }
+}
+
+impl Iterator for Seg<'_> {
+    fn next(&self) -> Option<&Seg> {
+        if let Ctr::Seg(s) = self.cdr {
+            Ok(s)
+        } else {
+            None()
+        }
+    }
 }
 
 impl Type {
-    pub fn to_str(&self) -> String {
+    pub fn to_string(&self) -> String {
         let ret: &str;
         match self {
             Type::Symbol => ret = "symbol",
@@ -95,84 +145,16 @@ impl Type {
     }
 }
 
-/* Prints a Syntax Tree as a string
- */
-pub fn ast_as_string(c: Ast, with_parens: bool) -> String {
-    let mut string = String::new();
-    let mut prn_space = true;
-    let seg = c.borrow();
-    match &seg.car {
-        Ctr::Symbol(s) => string.push_str(&s),
-        Ctr::String(s) => {
-            string.push('\'');
-            string.push_str(&s);
-            string.push('\'');
-        }
-        Ctr::Integer(i) => string = string + &i.to_string(),
-        Ctr::Float(f) => string = string + &f.to_string(),
-        Ctr::Bool(b) => string = string + &b.to_string(),
-        Ctr::Seg(c) => string.push_str(ast_as_string(c.clone(), true).as_str()),
-        Ctr::None => prn_space = false,
-    }
-
-    if prn_space {
-        string.push(' ');
-    }
-
-    match &seg.cdr {
-        Ctr::Symbol(s) => string.push_str(&s),
-        Ctr::String(s) => {
-            string.push('\'');
-            string.push_str(&s);
-            string.push('\'');
-        }
-        Ctr::Integer(i) => string = string + &i.to_string(),
-        Ctr::Float(f) => string = string + &f.to_string(),
-        Ctr::Bool(b) => string = string + &b.to_string(),
-        Ctr::Seg(c) => string.push_str(ast_as_string(c.clone(), false).as_str()),
-        Ctr::None => {
-            if prn_space {
-                string.pop();
-            }
-        }
-    }
-
-    // TODO: maybe a better way to do this
-    if with_parens {
-        let mut extra = String::from("(");
-        extra.push_str(&string);
-        extra.push(')');
-        string = extra
-    }
-    return string;
-}
-
-pub fn ast_to_string(c: Ast) -> String {
-    ast_as_string(c.clone(), true)
-}
-
-/* NOTE: "Standard form" is used here to refer to a list of segments
- * that resembles a typical linked list. This means that Car may hold whatever,
- * but Cdr must either be Seg or None.
- */
-
-/* Initializes a new ast node with segment car and cdr passed in
- */
-pub fn new_ast(car: Ctr, cdr: Ctr) -> Ast {
-    Rc::new(RefCell::new(Seg { car: car, cdr: cdr }))
-}
-
 /* applies a function across a list in standard form
  * function must take a Ctr and return a bool
  * short circuits on the first false returned.
  * also returns false on a non standard form list
  */
-pub fn circuit<F: FnMut(&Ctr) -> bool>(tree: Ast, func: &mut F) -> bool {
-    let inner = tree.borrow();
-    if func(&inner.car) {
-        match &inner.cdr {
+pub fn circuit<F: Fn(&Ctr)>(list: &Seg, func: &mut F) -> bool {
+    if func(&list.car) {
+        match list.cdr {
             Ctr::None => true,
-            Ctr::Seg(c) => circuit(c.clone(), func),
+            Ctr::Seg(l) => circuit(l, func),
             _ => false,
         }
     } else {
@@ -183,55 +165,46 @@ pub fn circuit<F: FnMut(&Ctr) -> bool>(tree: Ast, func: &mut F) -> bool {
 /* recurs over ast assumed to be list in standard form
  * returns length
  */
-pub fn list_len(tree: Ast) -> u128 {
-    match &tree.borrow().cdr {
-        Ctr::Seg(c) => list_len(c.clone()) + 1,
-        _ => 1,
-    }
+pub fn list_len(list: &Seg) -> u128 {
+    let mut len = 0;
+    circuit(list, &circuit(&mut |c: &Ctr| -> bool { len += 1; true }))
 }
 
 /* recurs over tree assumed to be list in standard form
  * returns clone of ctr at index provided
+ *
+ * TODO: return result (or option?)
  */
-pub fn list_idx(tree: Ast, idx: u128) -> Ctr {
-    let inner = tree.borrow();
+pub fn list_idx<'a>(list: &Seg, idx: u128) -> Ctr<'a> {
     if idx > 0 {
-        match &inner.cdr {
-            Ctr::None => Ctr::None,
-            Ctr::Seg(c) => list_idx(c.clone(), idx - 1),
-            _ => {
-                if idx == 1 {
-                    inner.cdr.clone()
-                } else {
-                    Ctr::None
-                }
-            }
+        if let Ctr::Seg(s) = list.car {
+            list_idx(s, idx - 1)
+        } else if idx == 1 {
+            list.cdr
+        } else {
+            Ctr::None
         }
     } else {
-        match inner.car {
-            Ctr::None => Ctr::None,
-            _ => inner.car.clone(),
-        }
+        list.car
     }
 }
 
 /* recurs over tree assumed to be list in standard form
  * appends object to end of list
+ *
+ * TODO: return result
  */
-pub fn list_append(tree: Ast, obj: Ctr) {
-    let mut inner = tree.borrow_mut();
-    match &inner.car {
-        Ctr::None => {
-            inner.car = obj;
-        }
-        _ => match &inner.cdr {
-            Ctr::None => {
-                inner.cdr = Ctr::Seg(new_ast(obj, Ctr::None));
-            }
-            Ctr::Seg(tr) => {
-                list_append(tr.clone(), obj);
-            }
-            _ => (),
-        },
+pub fn list_append<'a>(list: &Seg, obj: Ctr) {
+    if let Ctr::None = list.car {
+        list.car = obj;
+        return
+    }
+
+    if let Ctr::Seg(s) = list.cdr {
+        list_append(s, obj)
+    }
+
+    if let Ctr::None = list.cdr {
+        list.cdr = Ctr::Seg(&Seg{car:obj, cdr:Ctr::None})
     }
 }

src/stl.rs

@@ -19,6 +19,7 @@ use crate::append::get_append;
 use crate::func::{func_declare, FTable};
 use crate::segment::Ctr;
 use crate::str::{get_concat, get_echo};
+use crate::control::{get_if};
 use crate::vars::{get_export, VTable};
 use std::cell::RefCell;
 use std::rc::Rc;
@@ -53,5 +54,9 @@ pub fn get_stdlib(conf: Rc<RefCell<VTable>>) -> Result<Rc<RefCell<FTable>>, Stri
         return Err(s);
     }
 
+    if let Some(s) = func_declare(ft.clone(), Rc::new(RefCell::new(get_if()))) {
+        return Err(s);
+    }
+
     return Ok(ft);
 }