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This is a utils library for java 8 project. It include parsec combinators and sql generators library.

There is a newer version: 2.9.2

package jaskell.parsec;

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

/**
 * Created by Mars Liu on 2016-01-03.
 * Choice 算子是多路分支选择算子, choice 顺序检查所有分路,返回第一个成功的算子的解析结果.如果某个算子解析失败以后没有复位,则将其错误
 * 信息抛出.如果所有的分路都解析失败,抛出异常.
 */
public class Choice
    implements Parsec {
    private final List> parsecs;

    @Override
    public T parse(State s) throws EOFException, ParsecException {
        Exception err = null;
        Status status = s.status();
        for (Parsec psc : this.parsecs){
            try {
                return psc.parse(s);
            }catch (EOFException|ParsecException e){
                err = e;
                if(s.status()!=status){
                    throw e;
                }
            }
        }
        if(err == null){
            throw s.trap("Choice Error : All parsec parser failed.");
        } else {
            if(err instanceof EOFException) {
                throw (EOFException) err;
            }
            String message = String.format("Choice Error %s, stop at %s", err, s.status());
            throw s.trap(message);
        }
    }

    @SafeVarargs
    public Choice(Parsec ... parsecs) {
        this.parsecs = Arrays.asList(parsecs);
    }

    public Choice(List> parsecs) {
        this.parsecs = new ArrayList<>(parsecs);
    }

}