added !eval and documented it

svn: r11873

collects/handin-server/checker.ss

@@ -692,6 +692,9 @@
   (syntax-rules ()
     [(_ expr) (begin (!defined expr) (!integer* expr))]))
 
+(provide !eval)
+(define-syntax-rule (!eval expr) ((submission-eval) `expr))
+
 (provide !test)
 (define-syntax !test
   (syntax-rules ()

collects/handin-server/scribblings/checker.scrbl

@@ -213,8 +213,8 @@ Within the body of @scheme[check:], @scheme[users] and
 @scheme[submission] will be bound to the checker arguments---a
 (sorted) list of usernames and the submission as a byte string.  In
 addition to the functionality below, you can use
-@scheme[((submission-eval) expr)] to evaluate expressions in the
+@scheme[(!eval _expr)] (or @scheme[((submission-eval) '_expr)]) to
-submitted code context, and you can use
+evaluate expressions in the submitted code context, and you can use
 @scheme[(with-submission-bindings (id ...) body ...)] to evaluate the
 body when @scheme[id]'s are bound to their values from the submission
 code.}
@@ -354,6 +354,11 @@ code.}
   @scheme[equal?] forms are @italic{not} evaluated in the submission
   context.}
 
+@defform[(!eval expr)]{
+
+  Evaluate an arbitrary expession in the submission context.  This is
+  a simple shorthand for @scheme[((submission-eval) `expr)].}
+
 @defproc*[([(!all-covered) void?]
            [(!all-covered [proc (string? . -> . any)]) void?])]{