Add support for multiple units

README.org

@@ -1,16 +1,38 @@
-* units-global-mode
+* units-mode
 
 This mode uses [[https://www.gnu.org/software/units/units.html][gnu units]] to facilitate unit conversions inside emacs.
 
 *This package is a work in progress*
 
+* Contents :TOC:
+- [[#units-mode][units-mode]]
+- [[#features][Features]]
+- [[#installation][Installation]]
+- [[#examples][Examples]]
+  - [[#simple-conversion][Simple conversion]]
+  - [[#derived-units][Derived units]]
+  - [[#multiple-units][Multiple units]]
+
 * Features
 - [X] convert region to other units
-- [ ] check ~--conformable~ units
+- [X] check ~--conformable~ units for completion
+
+* Installation
+First clone this repo into your local machine, then you can load it.
+
+An example config using ~use-package~ is like this:
 
+#+begin_src emacs-lisp
+(use-package units-mode
+  :load-path "/path/to/units-mode"
+  :hook text-mode
+  :config
+  (local-set-key (kbd "C-c u") 'units-convert-region-and-insert))
+#+end_src
 
-* Example
 
+* Examples
+** Simple conversion
 If you have
 
     L = 23 ft
@@ -19,13 +41,33 @@ And you ran ~units-convert-region-and-insert~ while selecting ~23 ft~ you'll be
 
     L = 23 ft = 7010.4 mm
 
+    There is completion for the target unit, that is non-exhaustive. So feel free to type whatever unit you want to. But pressing tab will help you see some of them.
+
+** Derived units
+
 Similarly,
 
     g = 9.81 m/s^2
     g = 9.81 m/s^2 = 32.185039 ft/s^2
 
-There is completion for the target unit, that is non-exhaustive as it only includes defined units and not derived ones like ~ft/s^2~
+Completion only includes defined units and not derived ones like ~ft/s^2~, so you need to type it fully.
 
 Running ~units-convert-region~ will just show the converted results in the minibuffer.
 
 If there is errors, like units aren't matched then it'll end with the error from ~units~
+
+** Multiple units
+Since units can allow you to convert to multiple units, this package also can.
+
+For example using ~ft;in~ in ~1m~ here returns this:
+
+    L = 1m
+    L = 1m = 3 ft + 3.3700787 in
+    L = 1m = 3 ft + 3.3700787 in = 100 cm
+
+    As you can see in the third line, you can use that value again to convert to something else as ~units~ supports simple calculations on units.
+
+Also note that it'll remove the unit with 0 coefficient, for example converting ~1mile~ to ~ft;in~ will result in this:
+
+    L = 1mile
+    L = 1mile = 5280 ft

tests/units-tests.el

@@ -2,15 +2,44 @@
 
 ;; conversion tests
 (ert-deftest units-convert-single-test ()
-  (should (= (units-convert-single 10 "ft" "m") 3.048))
-  (should (= (units-convert-single 1 "m" "ft") 3.2808399))
-  (should (= (units-convert-single 1 "kg" "g") 1e3))
-  (should (= (units-convert-single 1 "hour" "seconds") (* 60 60)))
-  (should (= (units-convert-single 1 "day" "hour") 24)))
+  (should (= (string-to-number
+	      (units-convert-single 10 "ft" "m")) 3.048))
+  (should (= (string-to-number
+	      (units-convert-single 1 "m" "ft")) 3.2808399))
+  (should (= (string-to-number
+	      (units-convert-single 1 "kg" "g")) 1e3))
+  (should (= (string-to-number
+	      (units-convert-single 1 "hour" "seconds")) (* 60 60)))
+  (should (= (string-to-number
+	      (units-convert-single 1 "day" "hour")) 24)))
 
 (ert-deftest units-convert-test ()
-  (should (= (units-convert "10ft" "m") 3.048))
-  (should (= (units-convert "1 m" "ft") 3.2808399))
-  (should (= (units-convert "1kg" "g") 1e3))
-  (should (= (units-convert "1 hour" "seconds") (* 60 60)))
-  (should (= (units-convert "1 day" "hour") 24)))
+  (should (= (string-to-number
+	      (units-convert "10ft" "m")) 3.048))
+  (should (= (string-to-number
+	      (units-convert "1 m" "ft")) 3.2808399))
+  (should (= (string-to-number
+	      (units-convert "1kg" "g")) 1e3))
+  (should (= (string-to-number
+	      (units-convert "1 hour" "seconds")) (* 60 60)))
+  (should (= (string-to-number
+	      (units-convert "1 day" "hour")) 24))
+  (should (string= (units-convert "1.5 day" "day;hour") "1;12"))
+  (should (string= (units-convert ".5 day" "day;hour") "0;12")))
+
+(ert-deftest units-convert-formatted-test ()
+  (should (string=
+	   (units-convert-formatted "10ft" "m") "3.048 m"))
+  (should (string=
+	   (units-convert-formatted "1 m" "ft") "3.2808399 ft"))
+  (should (string=
+	   (units-convert-formatted "1kg" "g") "1000 g"))
+  (should (string=
+	   (units-convert-formatted "1 hour" "seconds") "3600 seconds"))
+  (should (string=
+	   (units-convert-formatted "1 day" "hours") "24 hours"))
+  (should (string=
+	   (units-convert-formatted "1.5 day" "day;hours")
+	   "1 day + 12 hours"))
+  (should (string=
+	   (units-convert-formatted ".5 day" "day;hours") "12 hours")))

units-mode.el

@@ -29,6 +29,7 @@
 ;; This is emacs interface to gnu units program <https://www.gnu.org/software/units/units.html>.
 
 ;;; Code:
+(require 'cl-lib)
 
 (defcustom units-binary-path "units"
   "Path to the units binary.")
@@ -56,15 +57,34 @@
 	   value)))
 
 (defun units-convert (value to-unit)
-  (let ((out-lines (split-string (string-trim-right (units-command value to-unit)) "\n")))
+  (let ((out-lines (split-string
+		    (string-trim-right
+		     (units-command value to-unit)) "\n")))
     (if (length= out-lines 1)
-	(string-to-number (car out-lines))
+	(car out-lines)
       (user-error "%s" (string-join out-lines "\n")))))
 
 (defun units-convert-single (value from-unit to-unit)
   (units-convert (format "%s %s" value from-unit) to-unit))
 
 
+(defun units-convert-formatted (value to-unit)
+  (let ((converted (units-convert value to-unit)))
+    (if (cl-search ";" to-unit)
+	(let ((values (split-string converted ";"))
+	      (units (split-string to-unit ";")))
+	  (string-join
+	   (cl-loop for val in values
+		    for unt in units
+		    if (> (string-to-number val) 0)
+		    collect (format "%s %s" val unt)) " + "))
+      (format "%s %s" converted to-unit))))
+
+(setq values (split-string "1;0;1" ";"))
+(setq units (split-string "m;cm;mm" ";"))
+
+
+
 (defun units-conformable-list (value)
   (split-string
    (string-trim
@@ -79,7 +99,7 @@
 	    (completing-read
 	     "Convert to: "
 	     (units-conformable-list region-text)))))
-  (message "%s" (units-convert region-text to-unit)))
+  (message "%s" (units-convert-formatted region-text to-unit)))
 
 (defun units-convert-region-and-insert (region-text to-unit)
   (interactive
@@ -90,13 +110,12 @@
 	    (completing-read
 	     "Convert to: "
 	     (units-conformable-list region-text)))))
-  (save-excursion
-    (goto-char (region-end))
-    (insert (concat " = "
-		    (number-to-string
-		     (units-convert region-text to-unit))
-		    " "
-		    to-unit))))
+  (goto-char (region-end))
+  (insert (concat " = "
+		  (units-convert-formatted region-text to-unit))))
+
+(define-minor-mode units-mode
+  "Minor mode for Calculations related to units.")
 
 (provide 'units-mode)