lib_type_helpers.py

"""
These functions are useful to facilitate programming using immutability.
"""
from lib_types import (
	Consonant,
	Phonet,
	VocalFolds,
	Vowel,
	VowelLength,
	Place,
	Manner,
	Airstream,
	SecondaryArticulation,
)


def is_consonant(phone: Phonet) -> bool:
	"""Whether a phone is a consonant"""
	return isinstance(phone, Consonant)


def is_vowel(phone: Phonet) -> bool:
	"""Whether a phone is a vowel"""
	return isinstance(phone, Vowel)


def with_vocal_folds(vocal_folds: VocalFolds, phone: Phonet) -> Phonet:
	"""
	Change the voicing of a phone to a particular voicing.
	"""
	if is_consonant(phone):
		return Consonant(
			vocal_folds,
			phone.place,
			phone.manner,
			phone.airstream,
			phone.secondary_articulation,
		)
	return Vowel(
		phone.height, phone.backness, phone.rounding, vocal_folds, phone.vowel_length
	)


def with_place(place: Place, phone: Phonet) -> Phonet:
	"""
	Change the place of articulation of a consonant to a particular place.
	Ignore vowels.
	"""
	# Do not change vowels, since they do not have a place of articulation.
	if is_vowel(phone):
		return phone

	# change the place of articulation of consonants.
	return Consonant(
		phone.vocal_folds,
		place,
		phone.manner,
		phone.airstream,
		phone.secondary_articulation,
	)


def with_manner(manner: Manner, phone: Phonet) -> Phonet:
	"""
	Change the manner of articulation of a consonant to a particular manner.
	Ignore vowels.
	"""
	# Do not change vowels, since they do not have a manner of articulation.
	if is_vowel(phone):
		return phone

	# change the manner of articulation of consonants.
	return Consonant(
		phone.vocal_folds,
		phone.place,
		manner,
		phone.airstream,
		phone.secondary_articulation,
	)


def with_airstream(airstream: Airstream, phone: Phonet) -> Phonet:
	"""
	Change the airstream mechanism of a consonant to a particular one.
	Ignore vowels.
	"""
	# Do not change vowels.
	if is_vowel(phone):
		return phone

	# change the airstream mechanism of consonants.
	return Consonant(
		phone.vocal_folds,
		phone.place,
		phone.manner,
		airstream,
		phone.secondary_articulation,
	)


def with_vowel_length(vowel_length: VowelLength, phone: Phonet) -> Phonet:
	"""
	Change the vowel length of a vowel to a particular voicing.
	Ignore consonants.
	"""
	# Do not change consonants, since they do not have a vowel length.
	if is_consonant(phone):
		return phone

	# Make the vowel extra-short.
	return Vowel(
		phone.height, phone.backness, phone.rounding, phone.vocal_folds, vowel_length
	)


def with_secondary_articulation(
	secondary_articulation: SecondaryArticulation, phone: Phonet
) -> Phonet:
	"""
	Change the secondary articulation of a consonant to a particular one.
	Ignore vowels.
	"""
	# Do not change vowels.
	if is_vowel(phone):
		return phone

	# change the secondary articulation of consonants.
	return Consonant(
		phone.vocal_folds,
		phone.place,
		phone.manner,
		phone.airstream,
		secondary_articulation,
	)


def to_extra_short(phone: Phonet) -> Phonet:
	"""
	Change the length of a vowel to
	extra short. Ignore consonants.
	"""
	return with_vowel_length(VowelLength.EXTRA_SHORT, phone)


def to_normal_length(phone: Phonet) -> Phonet:
	"""
	Change the length of a vowel to
	normal. Ignore consonants.
	"""
	return with_vowel_length(VowelLength.NORMAL, phone)


def to_long(phone: Phonet) -> Phonet:
	"""
	Change the length of a vowel to long.
	Ignore consonants.
	"""
	return with_vowel_length(VowelLength.LONG, phone)


def to_half_long(phone: Phonet) -> Phonet:
	"""
	Change the length of a vowel to half-long.
	Ignore consonants.
	"""
	return with_vowel_length(VowelLength.HALF_LONG, phone)


def to_alveolar(phone: Phonet) -> Phonet:
	""" Change the place of articulation to alveolar if phone is a consonant."""
	return with_place(Place.ALVEOLAR, phone)


def to_voiced(phone: Phonet) -> Phonet:
	"""Change the vocal folds to voiced."""
	return with_vocal_folds(VocalFolds.VOICED, phone)


def to_voiceless(phone: Phonet) -> Phonet:
	"""Change the vocal folds to voiceless."""
	return with_vocal_folds(VocalFolds.VOICELESS, phone)


def to_voiceless_aspirated(phone: Phonet) -> Phonet:
	"""Change the vocal folds to voiceless aspirated."""
	return with_vocal_folds(VocalFolds.VOICELESS_ASPIRATED, phone)


def to_voiced_aspirated(phone: Phonet) -> Phonet:
	"""Change the vocal folds to voiced aspirated."""
	return with_vocal_folds(VocalFolds.VOICED_ASPIRATED, phone)


def to_labialized(phone: Phonet) -> Phonet:
	"""Change the secondary articulation to labialized."""
	return with_secondary_articulation(SecondaryArticulation.LABIALIZED, phone)


def to_palatalized(phone: Phonet) -> Phonet:
	"""Change the secondary articulation to palatalized."""
	return with_secondary_articulation(SecondaryArticulation.PALATALIZED, phone)


def to_pharyngealized(phone: Phonet) -> Phonet:
	"""Change the secondary articulation to pharyngealized."""
	return with_secondary_articulation(SecondaryArticulation.PHARYNGEALIZED, phone)


def to_velarized(phone: Phonet) -> Phonet:
	"""Change the secondary articulation to velarized."""
	return with_secondary_articulation(SecondaryArticulation.VELARIZED, phone)