use icu::ListFormatter to combine a list strings into a string

libgnucash/engine/gnc-date.cpp

@@ -46,6 +46,7 @@
 
 #include <cinttypes>
 #include <unicode/calendar.h>
+#include <unicode/listformatter.h>
 
 #include "gnc-date.h"
 #include "gnc-date-p.h"
@@ -1652,3 +1653,29 @@ gnc_date_load_funcs (void)
     Testfuncs *tf = g_slice_new (Testfuncs);
     return tf;
 }
+
+
+gchar*
+gnc_list_formatter (GList *strings)
+{
+    g_return_val_if_fail (strings, nullptr);
+
+    UErrorCode status = U_ZERO_ERROR;
+    auto formatter = icu::ListFormatter::createInstance(status);
+    std::vector<icu::UnicodeString> strvec;
+    icu::UnicodeString result;
+    std::string retval;
+
+    for (auto n = strings; n; n = g_list_next (n))
+        strvec.push_back (static_cast<char*>(n->data));
+
+    formatter->format (strvec.data(), strvec.size(), result, status);
+
+    if (U_FAILURE(status))
+        PERR ("Unicode error");
+    else
+        result.toUTF8String(retval);
+
+    delete formatter;
+    return g_strdup (retval.c_str());
+}

libgnucash/engine/gnc-date.h

@@ -813,6 +813,17 @@ void gnc_gdate_set_prev_fiscal_year_start (GDate *date, const GDate *year_end);
  *  fiscal year.  The year field of this argument is ignored. */
 void gnc_gdate_set_prev_fiscal_year_end (GDate *date, const GDate *year_end);
 
+
+
+/** This function takes a GList of char*, and uses locale-sensitive
+ *  list formatter.
+ *
+ *  @param strings The GList* of char*.
+ *
+ * @returns a newly allocated char*
+ */
+gchar* gnc_list_formatter (GList* strings);
+
 //@}
 
 //@}