[gjs] format: Add support for numbered arguments

[Florian Müllner <fmuellner src gnome org>]

commit 4f40866c122688deddc70e90b6c6b4675a2a6caa
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Oct 13 05:36:26 2013 +0200

    format: Add support for numbered arguments
    
    When translating format strings with more than one conversion
    specification, it may be necessary to change the order in which
    arguments are applied. POSIX covers this use case by allowing
    either numbered or unnumbered arguments, it makes sense for us
    to support this as well.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=709907

 modules/format.js |   23 +++++++++++++++++------
 1 files changed, 17 insertions(+), 6 deletions(-)
---
diff --git a/modules/format.js b/modules/format.js
index e6b58d5..bf3d0a7 100644
--- a/modules/format.js
+++ b/modules/format.js
@@ -4,7 +4,8 @@ const GjsPrivate = imports.gi.GjsPrivate;
 
 function vprintf(str, args) {
     let i = 0;
-    return str.replace(/%(I+)?([0-9]+)?(?:\.([0-9]+))?(.)/g, function (str, flagsGroup, widthGroup, 
precisionGroup, genericGroup) {
+    let usePos = false;
+    return str.replace(/%(?:([1-9][0-9]*)\$)?(I+)?([0-9]+)?(?:\.([0-9]+))?(.)/g, function (str, posGroup, 
flagsGroup, widthGroup, precisionGroup, genericGroup) {
         if (precisionGroup != '' && genericGroup != 'f')
             throw new Error("Precision can only be specified for 'f'");
 
@@ -12,6 +13,12 @@ function vprintf(str, args) {
         if (hasAlternativeIntFlag && genericGroup != 'd')
             throw new Error("Alternative output digits can only be specfied for 'd'");
 
+        let pos = parseInt(posGroup, 10) || 0;
+        if (usePos == false && i == 0)
+            usePos = pos > 0;
+        if (usePos && pos == 0 || !usePos && pos > 0)
+            throw new Error("Numbered and unnumbered conversion specifications cannot be mixed");
+
         let fillChar = (widthGroup[0] == '0') ? '0' : ' ';
         let width = parseInt(widthGroup, 10) || 0;
 
@@ -22,29 +29,33 @@ function vprintf(str, args) {
             return fill.substr(s.length) + s;
         }
 
+        function getArg() {
+            return usePos ? args[pos - 1] : args[i++];
+        }
+
         let s = '';
         switch (genericGroup) {
         case '%':
             return '%';
             break;
         case 's':
-            s = String(args[i++]);
+            s = String(getArg());
             break;
         case 'd':
-            let intV = parseInt(args[i++]);
+            let intV = parseInt(getArg());
             if (hasAlternativeIntFlag)
                 s = GjsPrivate.format_int_alternative_output(intV);
             else
                 s = intV.toString();
             break;
         case 'x':
-            s = parseInt(args[i++]).toString(16);
+            s = parseInt(getArg()).toString(16);
             break;
         case 'f':
             if (precisionGroup == '')
-                s = parseFloat(args[i++]).toString();
+                s = parseFloat(getArg()).toString();
             else
-                s = parseFloat(args[i++]).toFixed(parseInt(precisionGroup));
+                s = parseFloat(getArg()).toFixed(parseInt(precisionGroup));
             break;
         default:
             throw new Error('Unsupported conversion character %' + genericGroup);