From 87e5c349350547cc1c198e763e9ce6a8df92018f Mon Sep 17 00:00:00 2001
From: Eli Barzilay <eli@racket-lang.org>
Date: Thu, 11 Dec 2008 21:05:03 +0000
Subject: [PATCH] use !defined for either syntax or simple binding, add !bound
 for a binding that cannot be a syntax

svn: r12781
---
 collects/handin-server/checker.ss                | 14 ++++++++++++++
 collects/handin-server/scribblings/checker.scrbl | 14 +++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/collects/handin-server/checker.ss b/collects/handin-server/checker.ss
index cff230911c..8d7e7e2b0c 100644
--- a/collects/handin-server/checker.ss
+++ b/collects/handin-server/checker.ss
@@ -655,8 +655,21 @@
 (define (get-namespace evaluator)
   (call-in-sandbox-context evaluator (lambda () (current-namespace))))
 
+;; checks that ids are defined, either as variables or syntaxes
 (provide !defined)
 (define-syntax-rule (!defined id ...)
+  ;; expected to be used only with identifiers
+  (begin (with-handlers ([exn:fail:contract:variable?
+                          (lambda (_)
+                            (error* "missing binding: ~e" (->disp 'id)))]
+                         [exn:fail:syntax? void])
+           (parameterize ([current-namespace (get-namespace (submission-eval))])
+             (namespace-variable-value `id)))
+         ...))
+
+;; checks that ids are defined as variables, not syntaxes
+(provide !bound)
+(define-syntax-rule (!bound id ...)
   ;; expected to be used only with identifiers
   (begin (with-handlers ([exn:fail:contract:variable?
                           (lambda (_)
@@ -669,6 +682,7 @@
              (namespace-variable-value `id)))
          ...))
 
+;; checks that ids are defined as syntaxes, not variables
 (provide !syntax)
 (define-syntax-rule (!syntax id ...)
   ;; expected to be used only with identifiers
diff --git a/collects/handin-server/scribblings/checker.scrbl b/collects/handin-server/scribblings/checker.scrbl
index 2d732ef102..7eb714f4d2 100644
--- a/collects/handin-server/scribblings/checker.scrbl
+++ b/collects/handin-server/scribblings/checker.scrbl
@@ -327,16 +327,20 @@ code.}
 
 @defform[(!defined id ...)]{
   Checks that the given identifiers are defined in the (evaluated)
-  submission, and throws an error otherwise.}
+  submission, and throws an error otherwise.  The identifiers can be
+  bound as either a plain value or as a syntax.}
 
-@defform[(!procedure id arity)]{
-
-  Checks that @scheme[id] is defined, and is bound to a procedure.}
+@defform[(!bound id ...)]{
+  Checks that the given identifiers are defined in the (evaluated)
+  submission as a plain value.  Throws an error if not, or if an
+  identifier is bound to a syntax.}
 
 @defform[(!syntax id arity)]{
-
   Checks that @scheme[id] is defined, and is bound as a macro.}
 
+@defform[(!procedure id arity)]{
+  Checks that @scheme[id] is defined, and is bound to a procedure.}
+
 @defform[(!procedure* expr arity)]{
 
   Similar to @scheme[!procedure] but omits the defined check, making