Prunes stem::length down to the bare minimum. (issue 5057041)

[mtsolo]

Reviewers: ,

Message:
A response to Neil's e-mail concerning stem::length - this is a cleaner
implementation.

Cheers,
MS

Description:
Prunes stem::length down to the bare minimum.

Please review this at http://codereview.appspot.com/5057041/

Affected files:
  M scm/output-lib.scm


Index: scm/output-lib.scm
diff --git a/scm/output-lib.scm b/scm/output-lib.scm
index  
70e3ba3eeb07885ff46475ec6f20b2a841dd01f8..33a2df36a70afcec5747ebaca2363028786e26a8  
100644
--- a/scm/output-lib.scm
+++ b/scm/output-lib.scm
@@ -73,17 +73,16 @@
    (ly:event-property (event-cause grob) 'duration)))

 (define-public (stem::length grob)
-  (let* ((d (ly:grob-property grob 'direction))
-         (ss (ly:staff-symbol-staff-space grob))
+  (let* ((ss (ly:staff-symbol-staff-space grob))
          (beg (ly:grob-property grob 'stem-begin-position))
          (beam (ly:grob-object grob 'beam)))
     (if (null? beam)
         (abs (- (ly:stem::calc-stem-end-position grob) beg))
-        (ly:grob-property grob 'length))))
+        (ly:programming-error
+          "stem::length called but will not be used for beamed stem."))))

 (define-public (stem::pure-length grob beg end)
-  (let* ((d (ly:grob-property grob 'direction))
-         (ss (ly:staff-symbol-staff-space grob))
+  (let* ((ss (ly:staff-symbol-staff-space grob))
          (beg (ly:grob-pure-property grob 'stem-begin-position 0 1000)))
     (abs (- (ly:stem::pure-calc-stem-end-position grob 0 2147483646)  
beg))))