From: Wolfgang Jenkner <wjenkner@inode.at>
Date: Fri, 26 Feb 2016 14:22:40 +0000 (+0100)
Subject: Add a work-around for bug#19582, present before Emacs 24.5.
X-Git-Url: https://code.delx.au/gnu-emacs-elpa/commitdiff_plain/4a0b5fb85ecd689346719881e149d1f4341b5da4

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.
---

diff --git a/packages/metar/metar.el b/packages/metar/metar.el
index 957531327..a05a353b9 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