CanonSharp/CanonSharp.Combinator/ParserBuilder.cs

using System.Runtime.CompilerServices;
using CanonSharp.Combinator.Abstractions;
using CanonSharp.Combinator.Extensions;
using CanonSharp.Combinator.Parsers.Bases;
using CanonSharp.Combinator.Parsers.Primitives;

namespace CanonSharp.Combinator;

public static class ParserBuilder
{
    #region PrimitiveParser

    // 对应Parsers.Primitives命名空间下的Parser实现

    /// <summary>
    /// 直接成功的解析器
    /// </summary>
    /// <param name="value"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Pure<TToken, T>(T value)
        => new PureParser<TToken, T>(value);

    /// <summary>
    /// 直接成功的解析器
    /// </summary>
    /// <param name="valueFunc">生成结果的函数</param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Pure<TToken, T>(Func<IReadState<TToken>, T> valueFunc)
        => new DelayedPureParser<TToken, T>(valueFunc);

    /// <summary>
    /// 生成空结果的解析器
    /// </summary>
    /// <typeparam name="TToken"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, Unit> Null<TToken>() => Pure<TToken, Unit>(Unit.Instance);

    /// <summary>
    /// 失败的解析器
    /// </summary>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Fail<TToken, T>() => new FailedParser<TToken, T>();

    /// <summary>
    /// 失败的解析器
    /// </summary>
    /// <param name="message">失败的原因</param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Fail<TToken, T>(string message) => new FailedParserWithMessage<TToken, T>(message);

    /// <summary>
    /// 失败的解析器
    /// </summary>
    /// <param name="messageFunc">产生失败原因的函数</param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Fail<TToken, T>(Func<IReadState<TToken>, string> messageFunc) =>
        new FailedParserWithDelayedMessage<TToken, T>(messageFunc);

    /// <summary>
    /// 失败的解析器
    /// </summary>
    /// <param name="exception">失败的异常</param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Fail<TToken, T>(Exception exception) =>
        new FailedParserWithException<TToken, T>(exception);

    /// <summary>
    /// 满足指定条件的解析器
    /// </summary>
    /// <param name="predicate"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, TToken> Satisfy<TToken>(Func<TToken, bool> predicate)
        => new SatisfyParser<TToken>(predicate);

    /// <summary>
    /// 识别任何输入的解析器
    /// </summary>
    /// <typeparam name="TToken"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, TToken> Any<TToken>() => Satisfy<TToken>(_ => true);

    /// <summary>
    /// 识别指定输入元素的解析器
    /// </summary>
    /// <param name="token">识别的指定元素</param>
    /// <typeparam name="TToken"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, TToken> Token<TToken>(TToken token)
        => Satisfy<TToken>(t => EqualityComparer<TToken>.Default.Equals(t, token));

    /// <summary>
    /// 跳过指定数量输入元素的解析器
    /// </summary>
    /// <param name="count"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, Unit> Skip<TToken>(int count) => new SkipParser<TToken>(count);

    /// <summary>
    /// 识别指定数量输入元素的解析器
    /// </summary>
    /// <param name="count"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, IEnumerable<TToken>> Take<TToken>(int count) => new TakeParser<TToken>(count);

    #endregion

    #region Bases

    /// <summary>
    /// 按照给定的函数修改解析器的解析器
    /// </summary>
    /// <param name="parserFix"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Fix<TToken, T>(Func<IParser<TToken, T>, IParser<TToken, T>> parserFix)
        => new FixParser<TToken, T>(parserFix);

    #endregion

    #region Combinators

    /// <summary>
    /// 按照给定的解析器组依次尝试
    /// </summary>
    /// <param name="parsers"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Choice<TToken, T>(IEnumerable<IParser<TToken, T>> parsers)
        => parsers.Aggregate((result, parser) => result.Alternative(parser));

    /// <summary>
    /// 按照给定的解析器组依次尝试
    /// </summary>
    /// <param name="parsers"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, T> Choice<TToken, T>(params IParser<TToken, T>[] parsers)
        => Choice(parsers.AsEnumerable());

    /// <summary>
    /// 顺序应用所有输入的解析器
    /// </summary>
    /// <param name="parsers"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, IEnumerable<T>> Sequence<TToken, T>(IEnumerable<IParser<TToken, T>> parsers)
        => parsers.Reverse().Aggregate(Pure<TToken, IEnumerable<T>>([]),
            (next, parser) => parser.Bind(
                x => next.Map(result => result.Prepend(x))));

    /// <summary>
    /// 顺序应用输入输入的解析器
    /// </summary>
    /// <param name="parsers"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, IEnumerable<T>> Sequence<TToken, T>(params IParser<TToken, T>[] parsers)
        => Sequence(parsers.AsEnumerable());

    /// <summary>
    /// 识别输入令牌直到终止解析器运行成功
    /// 在终止解析器之前可以存在零个或者多个输入令牌
    /// </summary>
    /// <param name="terminator"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="TIgnore"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, IEnumerable<TToken>> TakeTill<TToken, TIgnore>(IParser<TToken, TIgnore> terminator)
        => Any<TToken>().ManyTill(terminator);

    /// <summary>
    /// 识别输入令牌直到终止解析器运行成功
    /// 在终止解析器之前至少存在一个输入令牌
    /// </summary>
    /// <param name="termintor"></param>
    /// <typeparam name="TToken"></typeparam>
    /// <typeparam name="TIgnore"></typeparam>
    /// <returns></returns>
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static IParser<TToken, IEnumerable<TToken>> Take1Till<TToken, TIgnore>(IParser<TToken, TIgnore> termintor)
        => Any<TToken>().Many1Till(termintor);

    #endregion
}