Significant improvement to eval routine and tests

src/func.rs

@@ -81,7 +81,13 @@ pub fn func_call(
     let mut n_args: Ast = args.clone();
     if !called_func.eval_lazy {
         match eval(args, vars.clone(), funcs.clone(), called_func.loose_syms) {
-            Ok(rc_seg) => n_args = rc_seg.clone(),
+            Ok(rc_seg) => {
+                if let Ctr::Seg(ast) = rc_seg {
+                    n_args = ast
+                } else {
+                    return Err("Panicking: eval returned not a list for function args.".to_string())
+                }
+            },
             Err(s) => return Err(
                 format!(
                     "error evaluating args to {}: {}",
@@ -166,15 +172,32 @@ pub fn func_call(
                 );
             }
 
-            let result = eval(f.ast.clone(), vars.clone(), funcs, called_func.loose_syms);
+            let mut result = Ctr::None;
+            let mut iterate = f.ast.clone();
+            loop {
+                if let Ctr::Seg(ast) = iterate.borrow().clone().car {
+                    match eval(ast, vars.clone(), funcs.clone(), called_func.loose_syms) {
+                        Ok(ctr) => {
+                            if let Ctr::Seg(ast) = ctr {
+                                result = ast.borrow().clone().car;
+                            }
+                        },
+                        Err(e) => return Err(e)
+                    }
+                }
+
+                match iterate.clone().borrow().clone().cdr {
+                    Ctr::Seg(next) => iterate = next.clone(),
+                    Ctr::None => break,
+                    _ => panic!("function body not in standard form!")
+                }
+            }
+            
             for n in 0..f.arg_syms.len() {
                 vars.borrow_mut().remove(&f.arg_syms[n].clone());
             }
 
-            match result {
-                Ok(r) => Ok(r.borrow().clone().car),
-                Err(e) => Err(e)
-            }
+            return Ok(result)
         }
     }
 }