在C中扩展Ruby-将参数转换为C类型

Question

我该如何为红宝石做类似的事情。 我找不到将变量强制转换为对象的示例/文档。 例如

Local<Object> obj = args[0]->ToObject();
Local<Array> props = obj->GetPropertyNames();

我正在用ruby重新编写节点扩展。 任何形式的帮助都将非常有帮助。 谢谢

static Handle<Value> SendEmail(const Arguments& args)
{
    HandleScope scope;

    list<string> values;
    Local<Object> obj = args[0]->ToObject();
    Local<Array> props = obj->GetPropertyNames();

    // Iterate through args[0], adding each element to our list
    for(unsigned int i = 0; i < props->Length(); i++) {
        String::AsciiValue val(obj->Get(i)->ToString());
        values.push_front(string(*val));
    }

    // Display the values in the list for debugging purposes
    for (list<string>::iterator it = values.begin(); it != values.end(); it++) {
        cout << *it << endl;
    }

    return scope.Close(args.This());
}

Answer 1

当您将问题标记为C且您的代码示例是C ++时，我不确定是否能理解您的问题，但是无论哪种方式，如果您尝试扩展ruby，都需要将ruby值转换为C类型，如果计划使用C ++数据结构，则从C类型到C ++对象。

使用Ruby C Api：

#include "ruby.h"
//Define module my_module (this can be any name but it should be the name of your extension
VALUE MyModule = Qnil;
//Initialization prototype - required by ruby
void Init_MyModule();
//method prototype declarations - all methods must be prefaced by method_
VALUE method_get_some_ruby_value();

//actual method
VALUE get_some_ruby_value(VALUE self, VALUE some_value)
{
    //If your value is a ruby string - the StringValue function from ruby will ensure 
    //that you get a string no matter what, even if the type being passed is not a string.
    VALUE r_string_value = StringValue(some_value);

    //Now we tell the Ruby API to give us the pointer to the ruby string 
    //value and we assign that to a native char * in C. 
    char *c_string_value = RSTRING_PTR(r_string_value);

    //Now do something with the char * - for example, turn it into a C++ string
    std::string str(c_string_value);
    // ...do something useful here...

    return Qnil; // If you want to return something back to ruby, you can return a VALUE.   
}
//Ruby calls this to initialize your module in ruby
VALUE Init_MyModule()
{   
    //This defines your module in ruby
    MyModule = rb_define_module("MyModule");
    //This defines the method - the module it is in, the ruby method name, the actual method ruby will call, and the number of arguments this function is expected to take
    rb_define_method(MyModule, "get_some_ruby_value", get_some_ruby_value, 1);
}

如果您想了解在Ruby / C / C ++之间来回传递结构的知识，则在开始尝试使用C ++对象之前，需要对Ruby和Ruby C API有透彻的了解。

这里有一些很好的资源可以帮助您入门：

http://silverhammermba.github.io/emberb/c/ http://java.ociweb.com/mark/NFJS/RubyCExtensions.pdf