def parse_error(name):
"""
Instanciate a subtype of :class:`BaseError`, depending on the format of
``name``. We currently understand the following formats::
x -> InitTwiss
Δax_b3mu1 -> ElemAttr
δax_b3mu1 -> ScaleAttr
Δg3mu1->angle -> Param
δg3mu1->angle -> ScaleParam
g3mu1<dx> -> Ealign
"""
mult = name.startswith('δ')
name = name.lstrip('δΔ \t')
if name in ('x', 'y', 'px', 'py'):
return InitTwiss(name)
if '->' in name:
elem, attr = name.split('->')
if mult:
return ScaleAttr(elem, attr)
return ElemAttr(elem, attr)
if '<' in name:
elem, attr = re.match(r'(.*)\<(.*)\>', name).groups()
return Ealign({'range': elem}, attr)
if is_identifier(name):
if mult:
return ScaleParam(name)
return Param(name)
# TODO: efcomp field errors!
raise ValueError("{!r} is not a valid error specification!".format(name))
def _get_property_lval(elem, attr):
"""
Return lvalue name for a given element attribute from MAD-X.
>>> get_element_attribute(elements['r1qs1'], 'k1')
'r1qs1->k1'
"""
expr = elem[attr]
if isinstance(expr, list):
names = [_get_identifier(v) for v in expr]
if not any(names):
raise api.UnknownElement
return names
else:
name = _get_identifier(expr)
if is_identifier(name):
return name
return elem['name'] + '->' + attr
def test_is_identifier(self):
self.assertTrue(util.is_identifier('hdr23_oei'))
self.assertTrue(util.is_identifier('_hdr23_oei'))
self.assertFalse(util.is_identifier('2_hdr23_oei'))
self.assertFalse(util.is_identifier('hdr oei'))
self.assertFalse(util.is_identifier('hdr@oei'))
def test_is_identifier():
assert util.is_identifier('hdr23_oei')
assert util.is_identifier('_hdr23_oei')
assert not util.is_identifier('2_hdr23_oei')
assert not util.is_identifier('hdr oei')
assert not util.is_identifier('hdr@oei')
def test_is_identifier(self):
self.assertTrue(util.is_identifier('hdr23_oei'))
self.assertTrue(util.is_identifier('_hdr23_oei'))
self.assertFalse(util.is_identifier('2_hdr23_oei'))
self.assertFalse(util.is_identifier('hdr oei'))
self.assertFalse(util.is_identifier('hdr@oei'))
