def _read_lnk(tokens):
"""Read and return a tuple of the pred's lnk type and lnk value,
if a pred lnk is specified."""
# < FROM : TO > or < FROM # TO > or < TOK... > or < @ EDGE >
lnk = None
if tokens[0] == '<':
tokens.popleft() # we just checked this is a left angle
if tokens[0] == '>':
pass # empty <> brackets the same as no lnk specified
# edge lnk: ['@', EDGE, ...]
elif tokens[0] == '@':
tokens.popleft() # remove the @
lnk = Lnk.edge(tokens.popleft()) # edge lnks only have one number
# character span lnk: [FROM, ':', TO, ...]
elif tokens[1] == ':':
lnk = Lnk.charspan(tokens.popleft(), tokens[1])
tokens.popleft() # this should be the colon
tokens.popleft() # and this is the cto
# chart vertex range lnk: [FROM, '#', TO, ...]
elif tokens[1] == '#':
lnk = Lnk.chartspan(tokens.popleft(), tokens[1])
tokens.popleft() # this should be the hash
tokens.popleft() # and this is the to vertex
# tokens lnk: [(TOK,)+ ...]
else:
lnkdata = []
while tokens[0] != '>':
lnkdata.append(int(tokens.popleft()))
lnk = Lnk.tokens(lnkdata)
_read_literals(tokens, '>')
return lnk
def read_lnk(tokens):
"""Read and return a tuple of the pred's lnk type and lnk value,
if a pred lnk is specified."""
# < FROM : TO > or < FROM # TO > or < TOK... > or < @ EDGE >
lnk = None
if tokens[0] == _left_angle:
tokens.popleft() # we just checked this is a left angle
if tokens[0] == _right_angle:
pass # empty <> brackets the same as no lnk specified
# edge lnk: ['@', EDGE, ...]
elif tokens[0] == _at:
tokens.popleft() # remove the @
lnk = Lnk.edge(tokens.popleft()) # edge lnks only have one number
# character span lnk: [FROM, ':', TO, ...]
elif tokens[1] == _colon:
lnk = Lnk.charspan(tokens.popleft(), tokens[1])
tokens.popleft() # this should be the colon
tokens.popleft() # and this is the cto
# chart vertex range lnk: [FROM, '#', TO, ...]
elif tokens[1] == _hash:
lnk = Lnk.chartspan(tokens.popleft(), tokens[1])
tokens.popleft() # this should be the hash
tokens.popleft() # and this is the to vertex
# tokens lnk: [(TOK,)+ ...]
else:
lnkdata = []
while tokens[0] != _right_angle:
lnkdata.append(int(tokens.popleft()))
lnk = Lnk.tokens(lnkdata)
validate_token(tokens.popleft(), _right_angle)
return lnk
def testEdgeLnk(self):
lnk = Lnk.edge(1)
assert lnk.type == Lnk.EDGE
assert lnk.data == 1
assert str(lnk) == '<@1>'
repr(lnk) # no error
lnk = Lnk.edge('1')
assert lnk.data == 1
with pytest.raises(TypeError): Lnk.edge(None)
with pytest.raises(TypeError): Lnk.edge((1,))
with pytest.raises(ValueError): Lnk.edge('a')
