From 11f07080bd5db0380d1c688c53cb3a1a71eecdfd Mon Sep 17 00:00:00 2001
From: "William J. Bowman" <wjb@williamjbowman.com>
Date: Tue, 10 Nov 2015 16:30:46 -0500
Subject: [PATCH] More documentation

---
 scribblings/stdlib.scrbl     |  2 ++
 scribblings/stdlib/nat.scrbl | 69 ++++++++++++++++++++++++++++++++++++
 stdlib/nat.rkt               |  2 +-
 3 files changed, 72 insertions(+), 1 deletion(-)
 create mode 100644 scribblings/stdlib/nat.scrbl

diff --git a/scribblings/stdlib.scrbl b/scribblings/stdlib.scrbl
index fe4a1ea..4682c30 100644
--- a/scribblings/stdlib.scrbl
+++ b/scribblings/stdlib.scrbl
@@ -9,3 +9,5 @@ Cur has a small standard library, primary for demonstration purposes.
 
 @include-section{stdlib/tactics.scrbl}
 @include-section{stdlib/sugar.scrbl}
+@include-section{stdlib/bool.scrbl}
+@include-section{stdlib/nat.scrbl}
diff --git a/scribblings/stdlib/nat.scrbl b/scribblings/stdlib/nat.scrbl
new file mode 100644
index 0000000..cfbd3e3
--- /dev/null
+++ b/scribblings/stdlib/nat.scrbl
@@ -0,0 +1,69 @@
+#lang scribble/manual
+
+@(require
+  "../defs.rkt"
+  scribble/eval)
+
+@(define curnel-eval (curnel-sandbox "(require cur/stdlib/bool cur/stdlib/nat cur/stdlib/sugar)"))
+
+@title{Nat}
+@defmodule[cur/stdlib/nat]
+This library defines the datatype @racket[Nat] and several functions on them.
+
+@deftogether[(@defthing[Nat Type]
+              @defthing[z Nat]
+	      @defthing[s (-> Nat Nat)])]{
+The natural number datatype.
+}
+
+@defproc[(add1 [n Nat]) Nat]{
+A more lispy name for @racket[s].
+
+@examples[#:eval curnel-eval
+          (s z)
+	  (add1 z)]
+}
+
+@defproc[(sub1 [n Nat]) Nat]{
+Return the predecessor of @racket[n], or @racket[z] is @racket[n] is @racket[z].
+
+@examples[#:eval curnel-eval
+          (sub1 (s z))]
+
+}
+
+@defproc[(plus [n Nat] [m Nat]) Nat]{
+Add @racket[n] and @racket[m].
+
+@examples[#:eval curnel-eval
+          (plus (s z) (s z))
+	  (plus z (s z))
+	  (plus (s (s z)) (s z))]
+}
+
+@defproc[(nat-equal? [n Nat] [m Nat]) Bool]{
+Return @racket[true] if and only if @racket[n] is equal to @racket[m].
+
+@examples[#:eval curnel-eval
+          (nat-equal? (s z) (s z))
+	  (nat-equal? z (s z))]
+}
+
+@defproc[(even? [n Nat]) Bool]{
+Return @racket[true] if and only if @racket[n] is even.
+
+@examples[#:eval curnel-eval
+          (even? (s z))
+	  (even? z)
+	  (even? (s (s z)))]
+
+}
+
+@defproc[(odd? [n Nat]) Bool]{
+Return @racket[true] if and only if @racket[n] is not even.
+
+@examples[#:eval curnel-eval
+          (odd? (s z))
+	  (odd? z)
+	  (odd? (s (s z)))]
+}
diff --git a/stdlib/nat.rkt b/stdlib/nat.rkt
index f7bf650..85eced7 100644
--- a/stdlib/nat.rkt
+++ b/stdlib/nat.rkt
@@ -2,7 +2,7 @@
 (require "sugar.rkt" "bool.rkt")
 ;; TODO: override (all-defined-out) to enable exporting all these
 ;; properly.
-(provide Nat z s add1 sub1 plus )
+(provide Nat z s add1 sub1 plus nat-equal? even? odd?)
 (module+ test
   (require rackunit))