add lambda/this

1 files changed, 21 insertions, 0 deletions

diff --git a/README.md b/README.md
index 110f855..96a5fd2 100644
--- a/README.md
+++ b/README.md
@@ -10,3 +10,24 @@ Notable features:
 
 This is the first time I've written low-level CHICKEN code: use at your own
 risk.
+
+## Usage
+
+Import `(srfi 259)` for only the standard bindings. Import
+`(srfi 259 extensions)` for the SRFI-259 macro and the extensions
+described below.
+
+## Extensions
+
+This library implements lambdas with object scope.
+
+    (lambda/this this formal body ...)
+
+Create a procedure such that `this` will be bound to the current
+procedure.  When a new procedure is created using a tag constructor,
+`this` will point to the new procedure, not to the old procedure. This
+allows for a procedure to inspect its own tags.
+
+    (procedure/this? obj)
+
+Returns true if `obj` is a procedure created using `lambda/this`.