misc: add |sum template filter (#56380)

combo/public/templatetags/combo.py

@@ -725,3 +725,14 @@ def extra_context(cell, request):
     if hasattr(cell, 'repeat_index'):
         ctx['repeat_index'] = cell.repeat_index
     return ctx
+
+
+@register.filter(name='sum')
+def sum_(list_):
+    if isinstance(list_, str):
+        # do not consider string as iterable, to avoid misusage
+        return ''
+    try:
+        return sum(parse_decimal(term) for term in list_)
+    except TypeError:  # list_ is not iterable
+        return ''

tests/test_public_templatetags.py

@@ -894,3 +894,16 @@ def test_django_contrib_humanize_filters():
     with override_settings(LANGUAGE_CODE='fr-fr'):
         assert tmpl.render(Context({'foo': 10000})) == '10 000'
         assert tmpl.render(Context({'foo': '10000'})) == '10 000'
+
+
+def test_sum():
+    t = Template('{{ "2 29.5 9,5 .5"|split|sum }}')
+    assert t.render(Context()) == '41.5'
+    t = Template('{{ list|sum }}')
+    assert t.render(Context({'list': [1, 2, '3']})) == '6'
+    assert t.render(Context({'list': [1, 2, 'x']})) == '3'
+    assert t.render(Context({'list': [None, 2.0, 'x']})) == '2'
+    assert t.render(Context({'list': []})) == '0'
+    assert t.render(Context({'list': None})) == ''  # list is not iterable
+    assert t.render(Context({'list': '123'})) == ''  # consider string as not iterable
+    assert t.render(Context()) == ''