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• RegexGrammar.java

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io.github.ericmedvet.jgea.problem.extraction.string.RegexGrammar Maven / Gradle / Ivy

/*-
 * ========================LICENSE_START=================================
 * jgea-problem
 * %%
 * Copyright (C) 2018 - 2024 Eric Medvet
 * %%
 * 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
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =========================LICENSE_END==================================
 */

package io.github.ericmedvet.jgea.problem.extraction.string;

import io.github.ericmedvet.jgea.core.representation.grammar.string.StringGrammar;
import io.github.ericmedvet.jgea.core.util.Misc;
import io.github.ericmedvet.jgea.problem.extraction.ExtractionFitness;
import java.util.*;
import java.util.stream.Collectors;

public class RegexGrammar extends StringGrammar {

  public static final String TO_BE_ESCAPED = "{}[]()?+*.\\^";

  public RegexGrammar(Collection texts, Set options) {
    this(
        texts.stream()
            .map(s -> s.chars().mapToObj(c -> (char) c).collect(Collectors.toSet()))
            .reduce(Misc::union)
            .orElse(Set.of()),
        options);
  }

  public RegexGrammar(ExtractionFitness fitness, Set options) {
    this(
        fitness.getDesiredExtractions().stream()
            .map(r -> (Set)
                (new HashSet<>(fitness.getSequence().subList(r.min(), r.max()))))
            .reduce(Misc::union)
            .orElse(Set.of()),
        options);
  }

  public RegexGrammar(Set alphabet, Set options) {
    super();
    rules().put("", l(l("")));
    if (options.contains(Option.OR)) {
      rules().get("").add(l(""));
      rules().put("", l(l("", "|", "")));
    }
    rules().put("", l(l("", ""), l("")));
    if (options.contains(Option.ENHANCED_CONCATENATION)) {
      rules().get("").add(l("", ""));
    }
    rules().put("", l(l("")));
    if (options.contains(Option.QUANTIFIERS)) {
      rules().get("").add(l("", ""));
      rules().put("", l(l("?+"), l("++"), l("*+")));
    }
    rules().put("", l(l("")));
    if (options.contains(Option.NON_EMPTY_QUANTIFIER)) {
      rules().get("").add(l("", ""));
      rules().put("", l(l("++")));
    }
    if (options.contains(Option.BOUNDED_QUANTIFIERS)) {
      rules().get("").add(l("", "{", "", ",", "", "}"));
      rules().put("", l(l("1"), l("2"), l("3"), l("4"), l("5"), l("6"), l("7"), l("8"), l("9")));
    }
    rules().put("", l(l("")));
    if (options.contains(Option.CHAR_CLASS)) {
      rules().get("").add(l("[", "", "]"));
      rules().put("", l(l(""), l("", "")));
      if (options.contains(Option.ENHANCED_CONCATENATION)) {
        rules().get("").add(l("", ""));
      }
    }
    if (options.contains(Option.NEGATED_CHAR_CLASS)) {
      rules().get("").add(l("[^", "", "]"));
      rules().put("", l(l(""), l("", "")));
    }
    if (options.contains(Option.NON_CAPTURING_GROUP)) {
      rules().get("").add(l("(?:", "", ")"));
    }
    rules().put("", l(l("")));
    if (options.contains(Option.ANY)) {
      rules().get("").add(l("."));
    }
    rules().put("", new ArrayList<>());
    for (Character character : alphabet) {
      rules().get("").add(l(escape(character.toString())));
    }
    setStartingSymbol("");
  }

  public enum Option {
    OR,
    QUANTIFIERS,
    NON_EMPTY_QUANTIFIER,
    BOUNDED_QUANTIFIERS,
    CHAR_CLASS,
    NEGATED_CHAR_CLASS,
    NON_CAPTURING_GROUP,
    ANY,
    ENHANCED_CONCATENATION
  }

  private String escape(String c) {
    if (TO_BE_ESCAPED.contains(c)) {
      return "\\" + c;
    }
    return c;
  }

  @SafeVarargs
  private  List l(T... ts) {
    return new ArrayList<>(Arrays.asList(ts));
  }
}