week9 reference tweak

[lambda.git] / code / lambda.js

diff --git a/code/lambda.js b/code/lambda.js
index d4e3a5e..83ae7c4 100644 (file)
--- a/code/lambda.js
+++ b/code/lambda.js
@@ -423,6 +423,7 @@ function reduce(expr, eta, cbv) {
         return expr.eval_cbv(cbv > 1);
     } else {
         // return expr.eval_loop([], eta);
+               // using trampoline to reduce call stack overflows
                var to_eval = expr, res = [[], eta];
                while (to_eval !== null) {
                        res = to_eval.eval_loop.apply(to_eval, res);