1 files changed, 16 insertions, 0 deletions
diff --git a/talerbank/jinja2.py b/talerbank/jinja2.py
index b646162..9c2c52e 100644
--- a/talerbank/jinja2.py
+++ b/talerbank/jinja2.py
@@ -20,6 +20,7 @@
 #  @brief Extends the Jinja2 API with custom functions.
 
 import os
+import math
 from urllib.parse import urlparse
 from django.urls import reverse, get_script_prefix
 from django.conf import settings
@@ -108,6 +109,19 @@ def env_get(name, default=None):
 #
 # @param options opaque argument (?) given from the caller.
 # @return Jinja2-specific object that contains the new definitions.
+def is_valid_amount(amount):
+    if math.isnan(amount.value):
+        return False
+
+
+##
+# Stringifies amount.
+#
+# @param amount amount object.
+# @return amount pretty string.
+def amount_stringify(amount):
+    return amount.stringify(settings.TALER_DIGITS, pretty=True)
+
 def environment(**options):
     env = Environment(**options)
     env.globals.update({
@@ -115,5 +129,7 @@ def environment(**options):
         'url': url,
         'settings_value': settings_value,
         'env': env_get,
+        'is_valid_amount': is_valid_amount
+        'amount_stringify': amount_stringify
     })
     return env