add basic vowel features

2 files changed, 136 insertions, 0 deletions

diff --git a/src/language.test.ts b/src/language.test.ts
new file mode 100644
index 0000000..e9845a1
--- /dev/null
+++ b/src/language.test.ts
@@ -0,0 +1,33 @@
+import * as lang from './language';
+
+test('correctly output basic vowels', () => {
+	expect(lang.vowelFeaturesToIpa({
+		height: lang.VowelHeight.Close,
+		depth: lang.VowelDepth.Front,
+		round: false,
+		long: false,
+		nasal: false,
+	})).toBe('i');
+	expect(lang.vowelFeaturesToIpa({
+		height: lang.VowelHeight.Mid,
+		depth: lang.VowelDepth.Central,
+		round: false,
+		long: false,
+		nasal: false,
+	})).toBe('ə');
+	expect(lang.vowelFeaturesToIpa({
+		height: lang.VowelHeight.Open,
+		depth: lang.VowelDepth.Back,
+		round: true,
+		long: false,
+		nasal: true,
+	})).toBe('ɒ̃');
+	expect(lang.vowelFeaturesToIpa({
+		height: lang.VowelHeight.CloseMid,
+		depth: lang.VowelDepth.Front,
+		round: false,
+		long: true,
+		nasal: false,
+	})).toBe('eː');
+
+});
diff --git a/src/language.ts b/src/language.ts
new file mode 100644
index 0000000..2d0f547
--- /dev/null
+++ b/src/language.ts
@@ -0,0 +1,103 @@
+export enum VowelHeight {
+	Open,
+	NearOpen,
+	OpenMid,
+	Mid,
+	CloseMid,
+	NearClose,
+	Close,
+}
+export enum VowelDepth {
+	Front,
+	Central,
+	Back,
+}
+export interface VowelFeatures {
+	height: VowelHeight;
+	depth: VowelDepth;
+	round: boolean;
+	long: boolean;
+	nasal: boolean;
+}
+export function vowelFeaturesToIpa(features: VowelFeatures): string {
+	const ipa = () => {
+		switch (features.height) {
+			case VowelHeight.Open:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'ɶ' : 'a';
+				case VowelDepth.Central:
+				return features.round ? 'ɞ' : 'ä';
+				case VowelDepth.Back:
+				return features.round ? 'ɒ' : 'ɑ';
+			}
+
+			case VowelHeight.NearOpen:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'ɶ' : 'æ';
+				case VowelDepth.Central:
+				return features.round ? 'ɞ' : 'ɐ';
+				case VowelDepth.Back:
+				return features.round ? 'ɒ' : 'ɑ';
+			}
+
+			case VowelHeight.OpenMid:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'œ' : 'ɛ';
+				case VowelDepth.Central:
+				return features.round ? 'ɞ' : 'ɜ';
+				case VowelDepth.Back:
+				return features.round ? 'ɒ' : 'ɑ';
+			}
+
+			case VowelHeight.Mid:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'ø̞' : 'e̞';
+				case VowelDepth.Central:
+				return features.round ? 'ɵ' : 'ə';
+				case VowelDepth.Back:
+				return features.round ? 'o̞' : 'ɤ̞';
+			}
+
+			case VowelHeight.CloseMid:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'ø' : 'e';
+				case VowelDepth.Central:
+				return features.round ? 'ɵ' : 'ɘ';
+				case VowelDepth.Back:
+				return features.round ? 'o' : 'ɤ';
+			}
+
+			case VowelHeight.NearClose:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'ʏ' : 'ɪ';
+				case VowelDepth.Central:
+				return features.round ? 'ʉ' : 'ɨ';
+				case VowelDepth.Back:
+				return features.round ? 'u' : 'ʊ';
+			}
+
+			case VowelHeight.Close:
+			switch (features.depth) {
+				case VowelDepth.Front:
+				return features.round ? 'y' : 'i';
+				case VowelDepth.Central:
+				return features.round ? 'ʉ' : 'ɨ';
+				case VowelDepth.Back:
+				return features.round ? 'u' : 'ɯ';
+			}
+
+			default:
+			throw new Error(`bad vowel height: ${features.height}`);
+		}
+	};
+
+	const nasal = features.nasal ? '̃' : '';
+	const vlong = features.long ? 'ː' : '';
+	return ipa() + nasal + vlong;
+}