Merge pull request #13 from jackfirth/docs-core-#2

Add documentation of core form

command-line-ext/scribblings/core-form.scrbl

@@ -0,0 +1,23 @@
+#lang scribble/manual
+
+@(require package-scribblings-tools
+          (for-label command-line-ext
+                     racket/cmdline
+                     racket/base))
+
+@title{Core Forms}
+
+@defform[(command-line-ext maybe-name flag-clause ... final-clause)]{
+  Like @racket[command-line], but with a few important differences.
+  In addition to the normal options for @racket[flag-clause] that
+  @racket[command-line] allows, a flag clause may also be of the
+  form @racket[(begin-flags flag-clause ...)], which has exactly
+  the same semantics as if each @racket[flag-clause] contained
+  within @racket[begin-flags] was spliced into the surrounding
+  list of flag clauses. Additionally, @racket[command-line-ext]
+  supports @italic{command line flag expanders}, which are similar
+  to @racket[match] expanders and allow a user to extend the
+  grammar of @racket[flag-clause]. A custom @racket[flag-clause]
+  created with @racket[define-command-line-flag-expander] can
+  expand to multiple flag clauses by using @racket[begin-flags].
+}

command-line-ext/scribblings/main.scrbl

@@ -1,7 +1,6 @@
 #lang scribble/manual
 
-@(require scribble/eval
-          package-scribblings-tools
+@(require package-scribblings-tools
           (for-label command-line-ext
                      racket/cmdline
                      racket/base))