tests/test_templates.py

@@ -639,6 +639,40 @@ def test_abs_templatetag():
     assert tmpl.render({'value': None}) == '0'
 
 
+def test_clamp_templatetag():
+    tmpl = Template('{{ value|clamp:"3.5 5.5" }}')
+    assert tmpl.render({'value': 4}) == '4'
+    assert tmpl.render({'value': 6}) == '5.5'
+    assert tmpl.render({'value': 3}) == '3.5'
+    assert tmpl.render({'value': 'abc'}) == ''
+    assert tmpl.render({'value': None}) == ''
+
+    tmpl = Template('{{ value|clamp:"3.5 5.5 7.5" }}')
+    assert tmpl.render({'value': 4}) == ''
+
+    tmpl = Template('{{ value|clamp:"a b" }}')
+    assert tmpl.render({'value': 4}) == ''
+
+
+def test_limit_templatetags():
+    for v in (3.5, '"3.5"', 'xxx'):
+        tmpl = Template('{{ value|limit_low:%s }}' % v)
+        assert tmpl.render({'value': 4, 'xxx': 3.5}) == '4'
+        assert tmpl.render({'value': 3, 'xxx': 3.5}) == '3.5'
+        assert tmpl.render({'value': 'abc', 'xxx': 3.5}) == ''
+        assert tmpl.render({'value': None, 'xxx': 3.5}) == ''
+        if v == 'xxx':
+            assert tmpl.render({'value': 3, 'xxx': 'plop'}) == ''
+
+        tmpl = Template('{{ value|limit_high:%s }}' % v)
+        assert tmpl.render({'value': 4, 'xxx': 3.5}) == '3.5'
+        assert tmpl.render({'value': 3, 'xxx': 3.5}) == '3'
+        assert tmpl.render({'value': 'abc', 'xxx': 3.5}) == ''
+        assert tmpl.render({'value': None, 'xxx': 3.5}) == ''
+        if v == 'xxx':
+            assert tmpl.render({'value': 3, 'xxx': 'plop'}) == ''
+
+
 def test_token_decimal():
     tokens = [Template('{% token_decimal 4 %}').render() for i in range(100)]
     assert all(len(token) == 4 for token in tokens)

wcs/qommon/templatetags/qommon.py

@@ -640,6 +640,32 @@ def abs_(value):
     return decimal(abs(parse_decimal(value)))
 
 
+@register.filter
+def clamp(value, minmax):
+    try:
+        value = parse_decimal(value, do_raise=True)
+        min_value, max_value = (parse_decimal(x, do_raise=True) for x in unlazy(minmax).split())
+    except (ArithmeticError, TypeError, ValueError):
+        return ''
+    return max(min_value, min(value, max_value))
+
+
+@register.filter
+def limit_low(value, min_value):
+    try:
+        return max(parse_decimal(value, do_raise=True), parse_decimal(min_value, do_raise=True))
+    except (ArithmeticError, TypeError):
+        return ''
+
+
+@register.filter
+def limit_high(value, max_value):
+    try:
+        return min(parse_decimal(value, do_raise=True), parse_decimal(max_value, do_raise=True))
+    except (ArithmeticError, TypeError):
+        return ''
+
+
 @register.simple_tag
 def version_hash():
     from wcs.qommon.admin.menu import get_vc_version