refactor iterators to be closure objects

This makes iterators much more flexible while keeping their abstract
nature. New iterators can be made by a programmer with different
methods.

Existing iterator types cannot be programatically extended. This
would likely require implementation support: either CLOS-style
classes or a more limited single-dispatch interface system.

1 files changed, 6 insertions, 5 deletions

diff --git a/mcgoron.iterator.string.sld b/mcgoron.iterator.string.sld
index 9b8a388..ae2bb99 100644
--- a/mcgoron.iterator.string.sld
+++ b/mcgoron.iterator.string.sld
@@ -17,11 +17,12 @@
   (import (scheme base)
           (srfi 130) (srfi 128) (srfi 26)
           (mcgoron iterator base)
-          (mcgoron iterator exceptions))
-  (export cursor->iterator
+          (mcgoron iterator exceptions)
+          (mcgoron iterator string exceptions)
+          (mcgoron iterator srfi 128))
+  (export string-iterator
+          string-iterator?
           string-iterator-start
           string-iterator-end
-          string-index->iterator
-          string-iterator-constructor-exception?
-          string-iterator-constructor-exception:obj)
+          string-index->iterator)
   (include "mcgoron.iterator.string.scm"))