Question

I have defined a class with a single function. For example:

namespace my.namespace
{
    public class MyClass
    {
        public void some_func(string s1, string s2)
        {
            // more code here               
        }       
    }
}

I am able to load this object into an ironpython interpreter. I want to use introspection to get a list of methods that were implemented only in this class. In this example I want a list like ['some_func']. Is there a way to do it?

If I do a help(instance) on this instance I get more-or-less what I want:

class MyClass(object)
 |  MyClass()
 |  
 |  Methods defined here:
 |  
 |  __repr__(...)
 |      __repr__(self: object) -> str
 |  
 |  some_func(...)
 |      some_func(self: MyClass, s1: str, s2: str)

Of course, when I d a dir(instance) I get a lot of other functions:

>>> dir(instance)
['Equals', 'GetHashCode', 'GetType', 'MemberwiseClone', 'ReferenceEquals', 'ToString', '__class__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'some_func']

I want to know what instrospection method I need to use to get a list of only the functions unique to this class.

Answer 1

You have a number of options.

You can (explicitly) implement the IronPython.Runtime.IPythonMembersList interface that way you can list whatever members you want to list. It’s as if you defined the __dir__ method for your class.

public class MyClass : IronPython.Runtime.IPythonMembersList
{
    public void some_func(string s1, string s2) { }

    IList<object> IronPython.Runtime.IPythonMembersList.GetMemberNames(CodeContext context)
    {
        return new[] { "some_func" };
    }

    IList<string> Microsoft.Scripting.Runtime.IMembersList.GetMemberNames()
    {
        return new[] { "some_func" };
    }
}

You could always define a public __dir__ method for your class as well. The return type could be anything really, but you’ll probably want to return some collection of strings.

public class MyClass
{
    public void some_func(string s1, string s2) { }

    public IEnumerable<string> __dir__()
    {
        return new[] { "some_func" };
    }
}

You always have the option to use regular .NET reflection.

from System.Reflection import BindingFlags

# you can omit the flags if you want all public .NET members
flags = BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly

members = instance.GetType().GetMembers(flags)
dir_members = [ mi.Name for mi in members ]
print(dir_members)