Nemerle 宏的中缀格式

发布于 2024-07-06 21:54:42 字数 471 浏览 12 评论 0原文

假设我需要一些非常特殊的乘法运算符。它可以在以下宏中实现：

macro @<<!(op1, op2)
{
    <[ ( $op1 * $op2 ) ]>
}

我可以像使用它一样

def val = 2 <<! 3

和它的工作。

但我真正想要的是现在正在开发的 DSL 的一些类似于“英语”的运算符：

macro @multiply(op1, op2)
{
    <[ ( $op1 * $op2 ) ]>
}

如果我尝试使用它，就像

def val = 2 multiply 3

编译器因“预期”而失败一样错误

问题是什么？如何实现这个中缀格式的宏？

原文

Say I need some very special multiplication operator. It may be implemented in following macro:

macro @<<!(op1, op2)
{
    <[ ( $op1 * $op2 ) ]>
}

And I can use it like

def val = 2 <<! 3

And its work.

But what I really want is some 'english'-like operator for the DSL Im developing now:

macro @multiply(op1, op2)
{
    <[ ( $op1 * $op2 ) ]>
}

and if I try to use it like

def val = 2 multiply 3

compiler fails with 'expected ;' error

What is the problem? How can I implement this infix-format macro?

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习ぎ惯性依靠 2024-07-13 21:54:42

直接来自编译器源代码：

namespace Nemerle.English
{
  [assembly: Nemerle.Internal.OperatorAttribute ("Nemerle.English", "and", false, 160, 161)]
  [assembly: Nemerle.Internal.OperatorAttribute ("Nemerle.English", "or", false, 150, 151)]
  [assembly: Nemerle.Internal.OperatorAttribute ("Nemerle.English", "not", true, 181, 180)]  

  macro @and (e1, e2) {
    <[ $e1 && $e2 ]>
  }

  macro @or (e1, e2) {
    <[ $e1 || $e2 ]>
  }

  macro @not (e) {
    <[ ! $e ]>
  }

您需要散布 OperatorAttributes ，它就会起作用。顺便说一句，OperatorAttribute 定义如下：

public class OperatorAttribute : NemerleAttribute
{
  public mutable env : string;
  public mutable name : string;
  public mutable IsUnary : bool;
  public mutable left : int;
  public mutable right : int;
}

Straight from the compiler source code:

namespace Nemerle.English
{
  [assembly: Nemerle.Internal.OperatorAttribute ("Nemerle.English", "and", false, 160, 161)]
  [assembly: Nemerle.Internal.OperatorAttribute ("Nemerle.English", "or", false, 150, 151)]
  [assembly: Nemerle.Internal.OperatorAttribute ("Nemerle.English", "not", true, 181, 180)]  

  macro @and (e1, e2) {
    <[ $e1 && $e2 ]>
  }

  macro @or (e1, e2) {
    <[ $e1 || $e2 ]>
  }

  macro @not (e) {
    <[ ! $e ]>
  }

You need to sprinkle OperatorAttributes around and it will work. Btw, OperatorAttribute is defined as follows:

public class OperatorAttribute : NemerleAttribute
{
  public mutable env : string;
  public mutable name : string;
  public mutable IsUnary : bool;
  public mutable left : int;
  public mutable right : int;
}

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瀟灑尐姊 2024-07-13 21:54:42

像往常一样，我比社区回复更早找到答案:)
因此，解决方案是简单地使用特殊的 assemply level 属性，将宏指定为二元运算符：

namespace TestMacroLib
{
  [assembly: Nemerle.Internal.OperatorAttribute ("TestMacroLib", "multiply", false, 160, 161)]
  public macro multiply(op1, op2)
  {
    <[ ( $op1 * $op2 ) ]>
  }
}

As usually, I found answer sooner than comunity respond :)
So, solution is to simply use special assemply level attribute which specifies the macro as binary operator:

namespace TestMacroLib
{
  [assembly: Nemerle.Internal.OperatorAttribute ("TestMacroLib", "multiply", false, 160, 161)]
  public macro multiply(op1, op2)
  {
    <[ ( $op1 * $op2 ) ]>
  }
}

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