Indefinites

1 files changed, 67 insertions, 3 deletions

diff --git a/src/main/java/bjc/inflexion/EnglishUtils.java b/src/main/java/bjc/inflexion/EnglishUtils.java
index 28fc6c6..e233018 100644
--- a/src/main/java/bjc/inflexion/EnglishUtils.java
+++ b/src/main/java/bjc/inflexion/EnglishUtils.java
@@ -1,6 +1,4 @@
-/**
- * (C) Copyright 2017 Benjamin Culkin.
- *
+/*
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
@@ -15,6 +13,8 @@
  */
 package bjc.inflexion;
 
+import java.util.regex.Pattern;
+
 /**
  * General utils for dealing with english.
  *
@@ -72,4 +72,68 @@ public class EnglishUtils {
 
 		return "many";
 	}
+
+	private static Pattern AN_ORD = Pattern.compile("(?i)\\A[aefhilmnorsx]-?th\\Z");
+	private static Pattern A_ORD  = Pattern.compile("(?i)\\A[bcdgjkpqtuvwyz]-?th\\Z");
+	private static Pattern EXP_AN = Pattern.compile("(?i)\\A(?:euler|hour(?!i)|heir|honest|hono)");
+	private static Pattern SIN_AN = Pattern.compile("(?i)\\A[aefhilmnorst]\\Z");
+	private static Pattern SIN_A  = Pattern.compile("(?i)\\A[bcdgjkpqtuvwyz]\\Z");
+
+	private static Pattern ABBREV_AN = Pattern.compile("\\A(?!FJO|[HLMNS]Y|RY[EQ]|SQU|(F[LR]?|[HL]|MN?|N|RH?|S[CHKLMNPTVW]?|X(YL)?)[AEIOU])[FHLMNRSX][A-Z]");
+
+	private static Pattern IN_Y_AN = Pattern.compile("(?i)\\Ay(?:b[lor]|cl[ea]|fere|gg|p[ios]|rou|tt)");
+
+	private static Pattern ABBREV_C2 = Pattern.compile("(?i)\\A[aefhilmnorsx][.-]");
+	private static Pattern ABBREV_C3 = Pattern.compile("(?i)\\A[a-z][.-]");
+
+	private static Pattern CONSONANT = Pattern.compile("(?i)\\A[^aeiouy]");
+
+	private static Pattern SPECVOWEL_C1 = Pattern.compile("(?i)\\Ae[uw]");
+	private static Pattern SPECVOWEL_C2 = Pattern.compile("(?i)\\Aonc?e\b");
+	private static Pattern SPECVOWEL_C3 = Pattern.compile("(?i)\\Auni(?:[^nmd]|mo)");
+	private static Pattern SPECVOWEL_C4 = Pattern.compile("(?i)\\Aut[th]");
+	private static Pattern SPECVOWEL_C5 = Pattern.compile("(?i)\\Au[bcfhjkqrst][aeiou]");
+
+	private static Pattern SPECCAP_C1 = Pattern.compile("\\AU[NK][AIEO]?");
+
+	private static Pattern VOWEL = Pattern.compile("(?i)\\A[aeiou]\\Z");
+
+	public static String pickIndefinite(String word) {
+		// Handle ordinal forms
+		if(A_ORD.matcher(word).find()) return "a";
+		if(AN_ORD.matcher(word).find()) return "an";
+
+		// Handle special cases
+		if(EXP_AN.matcher(word).find()) return "an";
+		if(SIN_AN.matcher(word).find()) return "an";
+		if(SIN_A.matcher(word).find()) return "a";
+
+		// Handle abbreviations
+		if(ABBREV_AN.matcher(word).find()) return "an";
+		if(ABBREV_C2.matcher(word).find()) return "an";
+		if(ABBREV_C3.matcher(word).find()) return "a";
+
+		// Handle consonants
+		if(CONSONANT.matcher(word).find()) return "a";
+
+		// Handle special vowel forms
+		if(SPECVOWEL_C1.matcher(word).find()) return "a";
+		if(SPECVOWEL_C2.matcher(word).find()) return "a";
+		if(SPECVOWEL_C3.matcher(word).find()) return "a";
+		if(SPECVOWEL_C4.matcher(word).find()) return "an";
+		if(SPECVOWEL_C5.matcher(word).find()) return "a";
+
+		// Handle special capitals
+		if(SPECCAP_C1.matcher(word).find()) return "a";
+
+		// Handle vowels
+		if(VOWEL.matcher(word).find()) return "an";
+
+		// Handle Y (before certain consonants, it implies a
+		// (unnaturalized) "I" sound)
+		if(IN_Y_AN.matcher(word).find()) return "an";
+
+		// Guess "A"
+		return "a";
+	}
 }