lemmatizer: misc small improvements

lib/util/lemmatizer/lemmatizer.dart

@@ -38,9 +38,9 @@ class LemmatizationRule {
     required String pattern,
     required String? replacement,
     required WordClass wordClass,
-    validChildClasses,
-    terminal = false,
-    lookAheadBehind = const [''],
+    List<WordClass>? validChildClasses,
+    bool terminal = false,
+    List<Pattern> lookAheadBehind = const [''],
     LemmatizationRuleType type = LemmatizationRuleType.suffix,
   }) : this(
          name: name,
@@ -71,6 +71,7 @@ class AllomorphPattern {
     this.lookAheadBehind = const [''],
   });
 
+  /// Convert the [patterns] into regexes
   List<(String, Pattern)> get allPatternCombinations {
     final combinations = <(String, Pattern)>[];
     for (final l in lookAheadBehind) {
@@ -94,6 +95,7 @@ class AllomorphPattern {
     return combinations;
   }
 
+  /// Check whether an input string matches any of the [patterns]
   bool matches(String word) {
     for (final (_, p) in allPatternCombinations) {
       if (p is String) {
@@ -111,6 +113,9 @@ class AllomorphPattern {
     return false;
   }
 
+  /// Apply the replacement for this pattern.
+  ///
+  /// If none of the [patterns] apply, this function returns `null`.
   List<String>? apply(String word) {
     for (final (affix, p) in allPatternCombinations) {
       switch ((type, p is RegExp)) {
@@ -203,9 +208,10 @@ List<Lemmatized> _lemmatize(LemmatizationRule parentRule, String word) {
 
   final filteredLemmatizationRules = parentRule.validChildClasses == null
       ? lemmatizationRules
-      : lemmatizationRules.where(
-          (r) => parentRule.validChildClasses!.contains(r.wordClass),
-        );
+      : [
+          for (final wordClass in parentRule.validChildClasses!)
+            ...lemmatizationRulesByWordClass[wordClass]!,
+        ];
 
   for (final rule in filteredLemmatizationRules) {
     if (rule.matches(word)) {

lib/util/lemmatizer/rules.dart

@@ -3,8 +3,15 @@ import 'package:jadb/util/lemmatizer/rules/godan_verbs.dart';
 import 'package:jadb/util/lemmatizer/rules/i_adjectives.dart';
 import 'package:jadb/util/lemmatizer/rules/ichidan_verbs.dart';
 
-List<LemmatizationRule> lemmatizationRules = [
+final List<LemmatizationRule> lemmatizationRules = List.unmodifiable([
   ...ichidanVerbLemmatizationRules,
   ...godanVerbLemmatizationRules,
   ...iAdjectiveLemmatizationRules,
-];
+]);
+
+final Map<WordClass, List<LemmatizationRule>> lemmatizationRulesByWordClass =
+    Map.unmodifiable({
+      WordClass.ichidanVerb: ichidanVerbLemmatizationRules,
+      WordClass.iAdjective: iAdjectiveLemmatizationRules,
+      WordClass.godanVerb: godanVerbLemmatizationRules,
+    });

lib/util/lemmatizer/rules/godan_verbs.dart

@@ -479,7 +479,7 @@ final LemmatizationRule godanVerbNegativePastDesire = LemmatizationRule(
   wordClass: WordClass.godanVerb,
 );
 
-final List<LemmatizationRule> godanVerbLemmatizationRules = [
+final List<LemmatizationRule> godanVerbLemmatizationRules = List.unmodifiable([
   godanVerbBase,
   godanVerbNegative,
   godanVerbPast,
@@ -506,4 +506,4 @@ final List<LemmatizationRule> godanVerbLemmatizationRules = [
   godanVerbNegativeDesire,
   godanVerbPastDesire,
   godanVerbNegativePastDesire,
-];
+]);

lib/util/lemmatizer/rules/i_adjectives.dart

@@ -65,7 +65,7 @@ final LemmatizationRule iAdjectiveContinuative = LemmatizationRule.simple(
   wordClass: WordClass.iAdjective,
 );
 
-final List<LemmatizationRule> iAdjectiveLemmatizationRules = [
+final List<LemmatizationRule> iAdjectiveLemmatizationRules = List.unmodifiable([
   iAdjectiveBase,
   iAdjectiveNegative,
   iAdjectivePast,
@@ -74,4 +74,4 @@ final List<LemmatizationRule> iAdjectiveLemmatizationRules = [
   iAdjectiveConditional,
   iAdjectiveVolitional,
   iAdjectiveContinuative,
-];
+]);

lib/util/lemmatizer/rules/ichidan_verbs.dart

@@ -267,31 +267,32 @@ final LemmatizationRule ichidanVerbNegativePastDesire =
       wordClass: WordClass.ichidanVerb,
     );
 
-final List<LemmatizationRule> ichidanVerbLemmatizationRules = [
-  ichidanVerbBase,
-  ichidanVerbNegative,
-  ichidanVerbPast,
-  ichidanVerbTe,
-  ichidanVerbTeiru,
-  ichidanVerbTeita,
-  ichidanVerbConditional,
-  ichidanVerbVolitional,
-  ichidanVerbPotential,
-  ichidanVerbPassive,
-  ichidanVerbCausative,
-  ichidanVerbCausativePassive,
-  ichidanVerbImperative,
-  ichidanVerbNegativePast,
-  ichidanVerbNegativeTe,
-  ichidanVerbNegativeConditional,
-  ichidanVerbNegativeVolitional,
-  ichidanVerbNegativePotential,
-  ichidanVerbNegativePassive,
-  ichidanVerbNegativeCausative,
-  ichidanVerbNegativeCausativePassive,
-  ichidanVerbNegativeImperative,
-  ichidanVerbDesire,
-  ichidanVerbNegativeDesire,
-  ichidanVerbPastDesire,
-  ichidanVerbNegativePastDesire,
-];
+final List<LemmatizationRule> ichidanVerbLemmatizationRules =
+    List.unmodifiable([
+      ichidanVerbBase,
+      ichidanVerbNegative,
+      ichidanVerbPast,
+      ichidanVerbTe,
+      ichidanVerbTeiru,
+      ichidanVerbTeita,
+      ichidanVerbConditional,
+      ichidanVerbVolitional,
+      ichidanVerbPotential,
+      ichidanVerbPassive,
+      ichidanVerbCausative,
+      ichidanVerbCausativePassive,
+      ichidanVerbImperative,
+      ichidanVerbNegativePast,
+      ichidanVerbNegativeTe,
+      ichidanVerbNegativeConditional,
+      ichidanVerbNegativeVolitional,
+      ichidanVerbNegativePotential,
+      ichidanVerbNegativePassive,
+      ichidanVerbNegativeCausative,
+      ichidanVerbNegativeCausativePassive,
+      ichidanVerbNegativeImperative,
+      ichidanVerbDesire,
+      ichidanVerbNegativeDesire,
+      ichidanVerbPastDesire,
+      ichidanVerbNegativePastDesire,
+    ]);