use numbers as english words for numbers less than 21

Author: neverRare

src/translator/modifier.ts

@@ -8,7 +8,7 @@ import { determiner } from "./determiner.ts";
 import { ExhaustedError, TranslationTodoError } from "./error.ts";
 import { nanpa } from "./nanpa.ts";
 import { noun } from "./noun.ts";
-import { number } from "./number.ts";
+import { number, numberAsText } from "./number.ts";
 import { phrase } from "./phrase.ts";
 import { pronoun } from "./pronoun.ts";
 import { noEmphasis, word } from "./word.ts";
@@ -53,7 +53,7 @@ function defaultModifier(wordUnit: TokiPona.WordUnit) {
           type: "determiner",
           determiner: {
             determiner: word({
-              word: `${number}`,
+              word: numberAsText(number),
               reduplicationCount: 1,
               emphasis,
             }),

src/translator/number.ts

@@ -4,6 +4,29 @@ import { IterableResult } from "../compound.ts";
 import { dictionary } from "../dictionary.ts";
 import { FilteredError } from "./error.ts";
 
+const WORDS = [
+  "zero",
+  "one",
+  "two",
+  "three",
+  "four",
+  "five",
+  "six",
+  "seven",
+  "eight",
+  "nine",
+  "ten",
+  "eleven",
+  "twelve",
+  "thirteen",
+  "fourteen",
+  "fifteen",
+  "sixteen",
+  "seventeen",
+  "eighteen",
+  "nineteen",
+  "twenty",
+];
 function singleNumber(word: string) {
   return IterableResult.fromArray(dictionary.get(word)!.definitions)
     .filterMap((definition) =>
@@ -81,3 +104,10 @@ export function number(numbers: ReadonlyArray<string>): IterableResult<number> {
   return IterableResult.combine(...numbers.map(singleNumber))
     .flatMap(combineNumbers);
 }
+export function numberAsText(number: number): string {
+  if (number <= 20) {
+    return WORDS[number];
+  } else {
+    return `${number}`;
+  }
+}

src/translator/word_unit.ts

@@ -6,7 +6,7 @@ import { adjective, compoundAdjective } from "./adjective.ts";
 import * as English from "./ast.ts";
 import { TranslationTodoError } from "./error.ts";
 import { PartialNoun, partialNoun } from "./noun.ts";
-import { number } from "./number.ts";
+import { number, numberAsText } from "./number.ts";
 import { partialPronoun, Place } from "./pronoun.ts";
 import { PartialVerb, partialVerb } from "./verb.ts";
 import { word } from "./word.ts";
@@ -118,7 +118,7 @@ export function wordUnit(
           type: "noun",
           determiners: [],
           adjectives: [],
-          singular: `${number}`,
+          singular: numberAsText(number),
           plural: null,
           reduplicationCount: 1,
           emphasis: wordUnit.emphasis != null,