skele of eval function

src/eval.rs

@@ -17,7 +17,7 @@
 
 use std::rc::Rc;
 use std::cell::RefCell;
-use crate::segment::{Ast};
+use crate::segment::{Ast, Ctr};
 use crate::func::FTable;
 use crate::vars::VTable;
 
@@ -26,10 +26,45 @@ use crate::vars::VTable;
  * representing the simplest possible form of the input
  */
 pub fn eval(
-    _ast: Ast,
-    _vars: Rc<RefCell<VTable>>,
-    _funcs: Rc<RefCell<FTable>>,
-    _sym_loose: bool
+    ast: Ast,
+    vars: Rc<RefCell<VTable>>,
+    funcs: Rc<RefCell<FTable>>,
+    sym_loose: bool
 ) -> Result<Ast, String> {
-    Err("Unimplemented".to_string())
+    eval_inner(ast, vars, funcs, sym_loose, true)
+}
+
+fn eval_inner(
+    ast: Ast,
+    vars: Rc<RefCell<VTable>>,
+    funcs: Rc<RefCell<FTable>>,
+    sym_loose: bool,
+    first_item: bool
+) -> Result<Ast, String> {
+    /* TODO:
+     * 1. make new ast
+     * 2. call process_ctr on ast.car
+     * 3. set new.car to result
+     * 3. if cdr is an AST
+     *   - set first_item to false
+     *   - set new.cdr to recur of this
+     * 4. else call process_ctr on cdr
+     *    (and set new.cdr to result)
+     * 5. return new ast
+     */
+}
+
+fn process_ctr(
+    ctr: Ctr,
+    vars: Rc<RefCell<VTable>>,
+    funcs: Rc<RefCell<FTable>>,
+    sym_loose: bool,
+    first_item: bool
+) -> Result<Ctr, String> {
+    /* TODO:
+     *   1. if symbol, unwrap (DEEP COPY)
+     *   2. if first_item and symbol, call function?
+     *      (else: return var copy)
+     *   3. if list return result of eval()
+     *   4. finally, return a clone (shallow copy) of datum
 }