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, 24 insertions, 0 deletions

diff --git a/mcgoron.iterator.srfi.128.sld b/mcgoron.iterator.srfi.128.sld
new file mode 100644
index 0000000..712414c
--- /dev/null
+++ b/mcgoron.iterator.srfi.128.sld
@@ -0,0 +1,24 @@
+#| Copyright 2024 Peter McGoron
+ |
+ | Licensed under the Apache License, Version 2.0 (the "License");
+ | you may not use this file except in compliance with the License.
+ | You may obtain a copy of the License at
+ |
+ |     http://www.apache.org/licenses/LICENSE-2.0
+ |
+ | Unless required by applicable law or agreed to in writing, software
+ | distributed under the License is distributed on an "AS IS" BASIS,
+ | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ | See the License for the specific language governing permissions and
+ | limitations under the License.
+ |#
+
+(define-library (mcgoron iterator srfi 128)
+  (import (scheme base) (srfi 128)
+          (mcgoron iterator base))
+  (export get-iterator-comparator
+          iterator=?
+          iterator<? iterator<=?
+          iterator>? iterator>=?)
+  (include "mcgoron.iterator.srfi.128.scm"))
+