jaskell.parsec.common.Decimal Maven / Gradle / Ivy

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package jaskell.parsec.common;

import jaskell.parsec.ParsecException;

import java.io.EOFException;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by Mars Liu on 2016-01-08.
 * Decimal 尝试将后续的信息解析为 Decimal ,直到第一个无效信息为止.如果获取的信息不足以组成一个有效的浮点数,抛出异常.
 */
public class Decimal implements Parsec {
  private final Parsec sign = new Try<>(new Ch('-'));
  private final Parsec decimal = new UDecimal();

  @Override
  public String parse(State s)
      throws EOFException, ParsecException {
    if (sign.exec(s).isOk()){
      return "-" + decimal.parse(s);
    } else {
      return decimal.parse(s);
    }
  }
}