in progress commit

- fill out eval skele
- documentation comments in var tabel

src/eval.rs

@@ -41,13 +41,13 @@ fn eval_inner(
     sym_loose: bool,
     first_item: bool
 ) -> Result<Ast, String> {
-    /* TODO:
+    /* LOGIC:
      * 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
+     *   - set new.cdr to result of process_ctr(ast.ctr)
      * 4. else call process_ctr on cdr
      *    (and set new.cdr to result)
      * 5. return new ast
@@ -61,10 +61,34 @@ fn process_ctr(
     sym_loose: bool,
     first_item: bool
 ) -> Result<Ctr, String> {
-    /* TODO:
+    /* LOGIC:
      *   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
+     */
+
+    match ctr {
+        Symbol(token) => {
+            let mut tok = token;
+            if let Some(s) = vt.borrow().get(token) {
+                if first_item {
+                    if let String(t) = s {
+                        tok = t;
+                    } // else improper var type so ignore
+                } else {
+                    // TODO: DEEP COPY. return
+                }
+            } else if !first_item && !sym_loose {
+                return Err("variable not found")
+            }
+
+            if first_item && let Some(f) = ft.borrow().get(tok) {
+                // TODO: call function. set return
+            }
+        },
+        Seg(tree) => eval_inner(tree, vars, funcs, sym_loose, first_item),
+        _ => Ok(ctr.clone())
+    }
 }

src/vars.rs

@@ -26,6 +26,7 @@ use crate::segment::{Ctr};
  */
 pub type VTable = HashMap<String, Rc<Ctr>>;
 
+// WARNING: make sure var_tree is properly evaluated before storing
 pub fn define(
     vt: Rc<RefCell<VTable>>,
     identifier: String,