我已经从事我自己的ECMAScript实现了很长时间了.我基本上已经手工完成了所有事情,以帮助您深入了解该过程.反复尝试分析和理解语法的这一部分都失败了,所以我一直在研究项目的其他部分,但现在我正要研究对象字面量,因此我确实需要完善语法分析器.谁能用一个语言解析器新手可以理解的术语来表达？

我最大的困惑是：

new MemberExpression Arguments

这应该是一个成员表达式,但这似乎与以下内容冲突：

NewExpression :
    MemberExpression 
    new NewExpression

新表达式是成员表达式还是左侧表达式？老实说,我在为具体语法安排适当的C#类时遇到了麻烦.

MemberExpression : 
    PrimaryExpression 
    FunctionExpression 
    MemberExpression [ Expression ] 
    MemberExpression . IdentifierName 
    new MemberExpression Arguments 

NewExpression :
    MemberExpression 
    new NewExpression 

CallExpression :
    MemberExpression Arguments 
    CallExpression Arguments 
    CallExpression [ Expression ] 
    CallExpression . IdentifierName 

LeftHandSideExpression :
    NewExpression 
    CallExpression 

这是我一直在使用的班级设计,但是当我继续研究规范时,我的疑虑不会消失.

public abstract class LeftHandSideExpression : ConcreteExpression
{

}

public sealed class NewExpression : LeftHandSideExpression
{
    public NewExpression(MemberExpression memberExpression, Arguments arguments)
    {

    }

    public NewExpression(NewExpression newExpression, Arguments arguments)
    {

    }        
}

public sealed class CallExpression : LeftHandSideExpression
{
    public CallExpression(MemberExpression memberExpression, Arguments arguments)
    {

    }

    public CallExpression(CallExpression callExpression, Arguments arguments)
    {

    }
}

public sealed class MemberExpression : ConcreteExpression
{
    public MemberExpression(PrimaryExpression primaryExpression)
    {

    }

    public MemberExpression(PrimaryExpression primaryExpression, string identifierName)
    {

    }

    public MemberExpression(PrimaryExpression primaryExpression, ConcreteExpression indexerExpression)
    {

    }

    public MemberExpression(FunctionExpression functionExpression)
    {

    }

    public MemberExpression(FunctionExpression functionExpression, string identifierName)
    {

    }

    public MemberExpression(FunctionExpression functionExpression, ConcreteExpression indexerExpression)
    {

    }
}

基于安迪的回答,我想到了一个有意义的新设计.

public abstract class LeftHandSideExpression : ConcreteExpression
{
    public ConcreteExpression Expression { get; private set; }

    protected LeftHandSideExpression(ConcreteExpression expression)
    {
        Expression = expression;
    }
}

public class NewExpression : LeftHandSideExpression
{
    public Arguments Arguments { get; private set; }

    protected NewExpression(PrimaryExpression primaryExpression)
        : base(primaryExpression)
    {

    }

    protected NewExpression(FunctionExpression functionExpression)
        : base(functionExpression)
    {

    }

    protected NewExpression(MemberExpression memberExpression)
        : base(memberExpression)
    {

    }

    protected NewExpression(CallExpression callExpression)
        : base(callExpression)
    {

    }

    public NewExpression(MemberExpression memberExpression, Arguments arguments)
        : base(memberExpression)
    {
        Arguments = arguments;
    }

    public NewExpression(NewExpression newExpression, Arguments arguments)
        : base(newExpression)
    {
        Arguments = arguments;
    }      
}

public sealed class CallExpression : LeftHandSideExpression
{
    public Arguments Arguments { get; private set; }

    public CallExpression(MemberExpression memberExpression, Arguments arguments)
        : base(memberExpression)
    {
        Arguments = arguments;
    }

    public CallExpression(CallExpression callExpression, Arguments arguments)
        : base(callExpression)
    {
        Arguments = arguments;
    }
}

public class MemberExpression : NewExpression
{
    public MemberExpression(PrimaryExpression primaryExpression)
        : base(primaryExpression)
    {

    }

    public MemberExpression(FunctionExpression functionExpression)
        : base(functionExpression)
    {

    }

    public MemberExpression(MemberExpression memberExpression)
        : base(memberExpression)
    {

    }

    protected MemberExpression(CallExpression callExpression)
        : base(callExpression)
    {

    }
}

public sealed class DotPropertyAccessExpression : MemberExpression
{
    public string IdentifierName { get; private set; }

    public DotPropertyAccessExpression(PrimaryExpression primaryExpression, string identifierName)
        : base(primaryExpression)
    {
        IdentifierName = identifierName;
    }

    public DotPropertyAccessExpression(FunctionExpression functionExpression, string identifierName)
        : base(functionExpression)
    {
        IdentifierName = identifierName;
    }

    public DotPropertyAccessExpression(MemberExpression memberExpression, string identifierName)
        : base(memberExpression)
    {
        IdentifierName = identifierName;
    }

    public DotPropertyAccessExpression(CallExpression callExpression, string identifierName)
        : base(callExpression)
    {
        IdentifierName = identifierName;
    }
}

public sealed class BracketPropertyAccessExpression : MemberExpression
{
    public ConcreteExpression IndexerExpression { get; private set; }

    public BracketPropertyAccessExpression(PrimaryExpression primaryExpression, ConcreteExpression indexerExpression)
        : base(primaryExpression)
    {
        IndexerExpression = indexerExpression;
    }

    public BracketPropertyAccessExpression(FunctionExpression functionExpression, ConcreteExpression indexerExpression)
        : base(functionExpression)
    {
        IndexerExpression = indexerExpression;
    }

    public BracketPropertyAccessExpression(MemberExpression memberExpression, ConcreteExpression indexerExpression)
        : base(memberExpression)
    {
        IndexerExpression = indexerExpression;
    }

    public BracketPropertyAccessExpression(CallExpression callExpression, ConcreteExpression indexerExpression)
        : base(callExpression)
    {
        IndexerExpression = indexerExpression;
    }
}

解决方法:

这是一种不同的可视化方式.这是我在11.2节中看到生产的一般层次结构的方式：

LeftHandSideExpression :
    NewExpression :
        MemberExpression :
            PrimaryExpression
            FunctionExpression
            MemberExpression [ Expression ]
            MemberExpression . IdentifierName
            new MemberExpression Arguments
        new NewExpression
    CallExpression :
        MemberExpression Arguments
        CallExpression Arguments
        CallExpression [ Expression ]
        CallExpression . IdentifierName

看起来MemberExpressions是NewExpressions,它们依次是LeftHandSideExpressions.我希望这有帮助.