[elpa] master 4a0b5fb 2/2: Add a work-around for bug#19582, present before Emacs 24.5.

[Wolfgang Jenkner]

branch: master
commit 4a0b5fb85ecd689346719881e149d1f4341b5da4
Author: Wolfgang Jenkner <address@hidden>
Commit: Wolfgang Jenkner <address@hidden>

    Add a work-around for bug#19582, present before Emacs 24.5.
    
    * packages/metar/metar.el (metar-convert-unit): Rewrite expr if it
    starts with the `neg' operator.  Technically, this is wrong because
    various functions in calc-units expect already simplified
    expressions.  In practice, it should work around the above bug.
---
 packages/metar/metar.el |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/packages/metar/metar.el b/packages/metar/metar.el
index 9575313..a05a353 100644
--- a/packages/metar/metar.el
+++ b/packages/metar/metar.el
@@ -249,6 +249,9 @@ It must have the signature of `math-convert-units', which 
is the default."
   (unless (symbolp new-unit)
     (setq new-unit (intern new-unit)))
   (let ((expr (math-simplify (math-read-expr value))))
+    ;; Sneakily work around bug#19582.
+    (when (eq (car-safe expr) 'neg)
+      (setq expr `(* -1 ,(cadr expr))))
     (cl-assert (or (math-zerop expr)
                   (not (memq (math-single-units-in-expr-p expr) '(nil wrong))))
               nil