Make profile and profile-thunk return the value of the profiled expression.

Closes PR14404.

pkgs/profile-pkgs/profile-doc/profile/scribblings/toplevel.scrbl

@@ -26,11 +26,12 @@ intended as a convenient tool for profiling code.
                             (profile? . -> . any/c)))
            #f]
           [#:use-errortrace? use-errortrace? any/c #f])
-         void?]{
+         any/c]{
 
 Executes the given @racket[thunk] and collect profiling data during
-execution, eventually analyzing and rendering this.  Keyword arguments
-can customize the profiling:
+execution, eventually analyzing and rendering this. Returns the value
+of the profiled expression.
+Keyword arguments can customize the profiling:
 @itemize[
 
 @item{The profiler works by starting a ``sampler'' thread to
@@ -69,12 +70,7 @@ can customize the profiling:
 @item{Once the computation is done and the sampler is stopped, the
   accumulated data is analyzed (by @racket[analyze-samples]) and the
   resulting profile value is sent to the @racket[renderer] function.
-  See @secref["renderers"] for available renderers.  You can also use
-  @racket[values] as a ``renderer''---in this case
-  @racket[profile-thunk] returns the analyzed information which can
-  now be rendered multiple times, or saved for rendering directly
-  using one of the renderers, perhaps multiple times for different
-  views.}
+  See @secref["renderers"] for available renderers.}
 
 @item{To provide feedback information during execution, specify a
   @racket[periodic-renderer].  This should be a list holding a delay

pkgs/profile-pkgs/profile-lib/info.rkt

@@ -7,4 +7,4 @@
 
 (define pkg-desc "implementation (no documentation) part of \"profile\"")
 
-(define pkg-authors '(eli))
+(define pkg-authors '(eli stamourv))

pkgs/profile-pkgs/profile-lib/main.rkt

@@ -28,8 +28,8 @@
              (renderer (analyze-samples (sampler 'get-snapshots)))
              (loop))
            (thread loop))))
-  (define (run) (for ([i (in-range rpt)]) (thunk)))
-  (with-handlers ([void (λ (e) (eprintf "profiled thunk error: ~a\n"
+  (define (run) (for/last ([i (in-range rpt)]) (thunk)))
+  (begin0 (with-handlers ([void (λ (e) (eprintf "profiled thunk error: ~a\n"
                                                 (if (exn? e)
                                                     (exn-message e)
                                                     (format "~e" e))))])
@@ -38,7 +38,7 @@
                 (run)))
     (when periodic-thread (kill-thread periodic-thread))
     (sampler 'stop)
-  (renderer (analyze-samples (sampler 'get-snapshots))))
+    (renderer (analyze-samples (sampler 'get-snapshots)))))
 
 (define-syntax (profile stx)
   (syntax-case stx ()
@@ -85,3 +85,16 @@
          (list 0.5 text:render)
          )
 |#
+
+(module+ test
+  (require rackunit racket/string racket/list)
+  ;; `profile' and `profile-thunk' should return the value of the
+  ;; profiled expression
+  (check-equal?
+   (profile (for/last ([i (in-range 1000 5 -1)])
+              (string-join (map number->string (range i)))))
+   "0 1 2 3 4 5")
+  (check-equal?
+   (profile-thunk (lambda () (for/last ([i (in-range 1000 5 -1)])
+                               (string-join (map number->string (range i))))))
+   "0 1 2 3 4 5"))