c# - 从 C# 到 C++/CLI 的代码转换错误

Question

我尝试将 C# 的简单代码转换为 C++/CLI，但是当我尝试构建转换后的代码时，出现了以下错误:

1>------ Build started: Project: Compiler2, Configuration: Debug Win32 ------
1>  Source.cpp
1>Source.cpp(21): error C2143: syntax error : missing ';' before '^'
1>Source.cpp(21): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>Source.cpp(28): error C2143: syntax error : missing ';' before '^'
1>Source.cpp(28): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>Source.cpp(36): error C2143: syntax error : missing ';' before '^'
1>Source.cpp(36): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>Source.cpp(44): error C2143: syntax error : missing ';' before '^'
1>Source.cpp(44): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>Source.cpp(45): error C2143: syntax error : missing ';' before '^'
1>Source.cpp(45): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>Source.cpp(101): error C2146: syntax error : missing ';' before identifier 'Op'
1>Source.cpp(101): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

而且，我的代码是:

// AST.cs

using namespace System;

/* <stmt> := var <ident> = <expr>
    | <ident> = <expr>
    | for <ident> = <expr> to <expr> do <stmt> end
    | read_int <ident>
    | print <expr>
    | <stmt> ; <stmt>
  */
public ref class Stmt abstract
{
};

// var <ident> = <expr>
public ref class DeclareVar : Stmt
{
public:
    String^ Ident;
    Expr^ expr;
};

// print <expr>
public ref class Print : Stmt
{
public:
    Expr^ Expr;
};

// <ident> = <expr>
public ref class Assign : Stmt
{
public:
    String^ Ident;
    Expr^ Expr;
};

// for <ident> = <expr> to <expr> do <stmt> end
public ref class ForLoop : Stmt
{
public:
    String^ Ident;
    Expr^ From;
    Expr^ To;
    Stmt^ Body;
};

// read_int <ident>
public ref class ReadInt : Stmt
{
public:
    String^ Ident;
};

// <stmt> ; <stmt>
public ref class Sequence : Stmt
{
public:
    Stmt^ First;
    Stmt^ Second;
};

/* <expr> := <string>
 *  | <int>
 *  | <arith_expr>
 *  | <ident>
 */
public ref class Expr abstract
{
};

// <string> := " <string_elem>* "
public ref class StringLiteral : Expr
{
public:
    String^ Value;
};

// <int> := <digit>+
public ref class IntLiteral : Expr
{
public:
    int Value;
};

// <ident> := <char> <ident_rest>*
// <ident_rest> := <char> | <digit>
public ref class Variable : Expr
{
public:
    String^ Ident;
};

// <bin_expr> := <expr> <bin_op> <expr>
public ref class BinExpr : Expr
{
public:
    Expr^ Left;
    Expr^ Right;
    BinOp Op;
};

// <bin_op> := + | - | * | /
public enum class BinOp
{
    Add,
    Sub,
    Mul,
    Div
};

这段代码是从这段代码转换而来的:

// AST.cs

/* <stmt> := var <ident> = <expr>
    | <ident> = <expr>
    | for <ident> = <expr> to <expr> do <stmt> end
    | read_int <ident>
    | print <expr>
    | <stmt> ; <stmt>
  */
public abstract class Stmt
{
}

// var <ident> = <expr>
public class DeclareVar : Stmt
{
    public string Ident;
    public Expr Expr;
}

// print <expr>
public class Print : Stmt
{
    public Expr Expr;
}

// <ident> = <expr>
public class Assign : Stmt
{
    public string Ident;
    public Expr Expr;
}

// for <ident> = <expr> to <expr> do <stmt> end
public class ForLoop : Stmt
{
    public string Ident;
    public Expr From;
    public Expr To;
    public Stmt Body;
}

// read_int <ident>
public class ReadInt : Stmt
{
    public string Ident;
}

// <stmt> ; <stmt>
public class Sequence : Stmt
{
    public Stmt First;
    public Stmt Second;
}

/* <expr> := <string>
 *  | <int>
 *  | <arith_expr>
 *  | <ident>
 */
public abstract class Expr
{
}

// <string> := " <string_elem>* "
public class StringLiteral : Expr
{
    public string Value;
}

// <int> := <digit>+
public class IntLiteral : Expr
{
    public int Value;
}

// <ident> := <char> <ident_rest>*
// <ident_rest> := <char> | <digit>
public class Variable : Expr
{
    public string Ident;
}

// <bin_expr> := <expr> <bin_op> <expr>
public class BinExpr : Expr
{
    public Expr Left;
    public Expr Right;
    public BinOp Op;
}

// <bin_op> := + | - | * | /
public enum BinOp
{
    Add,
    Sub,
    Mul,
    Div
}

好的，我该如何解决这个错误？？ (因为，对我来说，代码是正确的...)

Answer 1

Expr 和 BinOp 在声明之前就被使用了；在 C# 中不是问题，但在 C++ 中是问题

试试这个

using namespace System;

/* <stmt> := var <ident> = <expr>
    | <ident> = <expr>
    | for <ident> = <expr> to <expr> do <stmt> end
    | read_int <ident>
    | print <expr>
    | <stmt> ; <stmt>
  */
public ref class Stmt abstract
{
};

/* <expr> := <string>
 *  | <int>
 *  | <arith_expr>
 *  | <ident>
 */
public ref class Expr abstract
{
};

// <bin_op> := + | - | * | /
public enum class BinOp
{
    Add,
    Sub,
    Mul,
    Div
};

// var <ident> = <expr>
public ref class DeclareVar : Stmt
{
public:
    String^ Ident;
    Expr^ expr;
};

// print <expr>
public ref class Print : Stmt
{
public:
    Expr^ Expr;
};

// <ident> = <expr>
public ref class Assign : Stmt
{
public:
    String^ Ident;
    Expr^ Expr;
};

// for <ident> = <expr> to <expr> do <stmt> end
public ref class ForLoop : Stmt
{
public:
    String^ Ident;
    Expr^ From;
    Expr^ To;
    Stmt^ Body;
};

// read_int <ident>
public ref class ReadInt : Stmt
{
public:
    String^ Ident;
};

// <stmt> ; <stmt>
public ref class Sequence : Stmt
{
public:
    Stmt^ First;
    Stmt^ Second;
};



// <string> := " <string_elem>* "
public ref class StringLiteral : Expr
{
public:
    String^ Value;
};

// <int> := <digit>+
public ref class IntLiteral : Expr
{
public:
    int Value;
};

// <ident> := <char> <ident_rest>*
// <ident_rest> := <char> | <digit>
public ref class Variable : Expr
{
public:
    String^ Ident;
};

// <bin_expr> := <expr> <bin_op> <expr>
public ref class BinExpr : Expr
{
public:
    Expr^ Left;
    Expr^ Right;
    BinOp Op;
};