Merge pull request 'Add method to test whether a string is a valid pinyin with tone number syllable' (#1) from add-is-valid-method into main

Reviewed-on: #1

src/main/kotlin/com/marvinelsen/chinese/transliteration/Syllable.kt

@@ -2,6 +2,7 @@ package com.marvinelsen.chinese.transliteration
 
 import java.io.InputStream
 
+@Suppress("MagicNumber", "MaximumLineLength", "MaxLineLength")
 data class Syllable(
     val pinyinSyllableWithoutTone: String,
     val tone: Tone,
@@ -13,6 +14,9 @@ data class Syllable(
         private val zhuyinToPinyin = pinyinToZhuyin.entries.associate { it.value to it.key }
         private val zhuyinToneMarkRegex = """[ˊˇˋ˙]""".toRegex()
 
+        fun isValidPinyinWithToneNumberSyllable(pinyinSyllable: String) =
+            pinyinSyllable.last().isDigit() && pinyinSyllable.last().digitToInt() in 1..5 && pinyinSyllable.lowercase() in pinyinToZhuyin
+
         fun fromPinyinWithToneNumber(pinyinWithToneNumber: String): Syllable {
             val pinyinWithoutNumber = pinyinWithToneNumber.substring(0, pinyinWithToneNumber.lastIndex)
             val lastCharacter = pinyinWithToneNumber.last()
@@ -20,7 +24,6 @@ data class Syllable(
             require(lastCharacter.isDigit()) {
                 "'$pinyinWithToneNumber' is not a valid Pinyin with tone number syllable. Expected the last character to be a digit, but was '${pinyinWithToneNumber.last()}'"
             }
-            @Suppress("MagicNumber")
             require(lastCharacter.digitToInt() in 1..5) {
                 "'$pinyinWithToneNumber' is not a valid Pinyin with tone number syllable. Expected the tone number 'n' to be in range 1 <= n <= 5, but was '${pinyinWithToneNumber.last()}'"
             }