def change_feature(self, args):
"""
This translates unconditional changes where the domain and codomain
are both feature expressions. The change_feature function from the
change_functions module is used to change each feature individually.
Finally, the created change object is given the condition of a
predicate that matches the feature values passed in for the domain.
:param list args: Two feature expressions, parsed into dictionaries.
:returns: A Change object.
"""
domain, codomain = args[0], args[1]
ch = Change()
for name, value in codomain.items():
ch = ch.do(lambda td: change_functions.change_feature(
td.phoneme, name, value))
def match_features(p, fdict=domain):
"""
Function that closes over the change domain.
Matches the domain feature values with the
target phoneme's features.
"""
for name, value in fdict.items():
if not p.feature_is(name, value):
return False
return True
ch = ch.to(This.forall(Phone)(match_features))
return ch
def intervocal_voicing(this):
return change.Change().do(
lambda this: change_functions.change_feature(
this.phoneme, "voice", True)).to(
change.This.forall(Phone)(make_predicate(this))).when(
change.This.at(Phone, -1, lambda p: p.is_vowel())).when(
change.This.at(Phone, 1, lambda p: p.is_vowel()))
def lengthen(phone):
return change.Change().do(
lambda this: change_functions.change_feature(
this.phoneme, "long", True)
).to(change.This.forall(Phone)(make_predicate(phone)))