dotnet/roslyn

The .NET Compiler Platform ("Roslyn") provides open-source C# and Visual Basic compilers with rich code analysis APIs.

Mohammad Hamdy Ghanem

@VBAndCs

But since when this is working in VB?

@VBAndCs Note that your extension method is on (int, int, int), but you're calling it on (int, int) just above. Those are different types

I have a two-item version.

using System;
using System.Collections;
using System.Runtime.CompilerServices;

foreach (int i in 20..10)
    Console.WriteLine(i);

foreach (int i in (10, -10))
    Console.WriteLine(i);

foreach (int i in (-10, 10, 3))
    Console.WriteLine(i);


public static class Extensions
{
    public static IEnumerator GetEnumerator(this System.Range range)
    {
        int start = range.Start.Value;
        int end = range.End.Value;
        if (end > start)
            for (int i = start; i <= end; i++)
                yield return i;
        else
            for (int i = start; i >= end; i--)
                yield return i;
    }

    public static IEnumerator GetEnumerator(this System.ValueTuple<int, int> range)
    {
        int start = range.Item1;
        int end = range.Item2;
        if (end > start)
            for (int i = start; i <= end; i++)
                yield return i;
        else
            for (int i = start; i >= end; i--)
                yield return i;
    }

    public static IEnumerator GetEnumerator(this System.ValueTuple<int, int, int> range)
    {
        int start = range.Item1;
        int end = range.Item2;
        int step = range.Item3;

        if (step > 0)
            for (int i = start; i <= end; i+=step)
                yield return i;
        else
            for (int i = start; i >= end; i += step)
                yield return i;
    }

}

Antony Male

@canton7

... and that works fine when you do var e = (1, 2).GetEnumerator()

Joe4evr

@Joe4evr

VB is complaining when you have a ForEach loop over an IEnumerator

of note, C# would do the same thing - there's an open-standing request to allow foreach-ing over an enumerator

Yair Halberstadt

@YairHalberstadt

@canton7 maybe it always worked in VB... I definitely didn't add it.

Mohammad Hamdy Ghanem

@VBAndCs

Thanks. This was helpful :). At least we discovered something new in VB.NET :).

Michael Fry

@nth-commit

Does anyone know of any guides which describe the relationship/non-relationship between the semantic model and System.Reflection? It's something I bump into all the time and haven't quite taken the time to understand. I am super familiar with navigating around System.Reflection and doing dynamic type stuff. Not so familiar with navigating around the semantic model (e.g. Compilation, ITypeSymbol). It would be nice if there was something I could read through which would help relate my familiarity with the former to the latter.

CyrusNajmabadi

@CyrusNajmabadi

There's no API relation. In that there no strong way to tie the entities from one to another.

However, there is a weak relation. System.Reflection allows for an API for a few purposes: introspecting metadata and querying against live values at runtime.

The Roslyn symbol model rejects reflects the static semantics of code at compile time.

There are many similar ideas in both.

For example PropertyInfo in reflection, and IPropertySymbol in Roslyn.

Roslyn has no runtime querying concept though*. It's all (mostly) about the information at compile time.

Michael Fry

@nth-commit

Thanks :)

Yeah I understand. Although a large portion of System.Reflection is to do with statically available info (obviously I don't expect roslyn to be able to give me runtime values if there isn't a program running, so there's no representation of CreateInstance, SetValue, GetValue etc.).

For example PropertyInfo in reflection, and IPropertySymbol in Roslyn

This is the stuff I want to hear about :D. I just want to know if these kinds of relationships are documented somewhere - and is it a value that the roslyn team hold or is any symmetry between the APIs incidental?

CyrusNajmabadi

@CyrusNajmabadi

Both? :-)

Both the language and the bcl need to represent things from metadata. And metadata in c# is produced from source. So there's are just common ways of representing those entities.

timiil

@timiil

Is there any opensource solution that use Roslyn to 'obfuscation' or 'protect' .NET PE ?

Bernd Baumanns

@bernd5

roslyn only emits IL - but it doesn't modify it

Yair Halberstadt

@YairHalberstadt

IsNullableTypeOrTypeParameter (https://sourceroslyn.io/#Microsoft.CodeAnalysis.CSharp/Symbols/TypeSymbolExtensions.cs,113) checks if a constraint type is a nullable type.

But how is this ever possible since structs can't be constraints? Is it only if the constraint is defined in a different language?

Mohammad Hamdy Ghanem

@VBAndCs

Languages are getting more complex (esp C#). It would be helpful for beginners and maybe old dves as mine if ther is an action named explain or whatever to lower a code block to a classic simple C#/VB code and show it in a readoly code window. Pattern matching expressions are in top of things that may need explanation. I may go far and say every new concept since Roslyn can be considered hard and nee to be explained. This can be a useful educational feature, and ease the pain for new team members that joins a large project. VS offers to simplify expressions which in most cases means shorten them into a complex modern syntax! We may need an action on the opposite direction. This seems a lot of work, but it can make use of the Roslyn code itself if it lowers these statements.

timiil

@timiil

roslyn only emits IL - but it doesn't modify it

i am looking for some 'name obfuscation Analyzer' or 'string encrypt Analyzer' ... 'XXX protect sourcecode Analyzer' things that build from roslyn...

Bernd Baumanns

@bernd5

if you have the csharp source you can write some rewriters which renames locals and non public types / methods

timiil

@timiil

https://github.com/nwtsolution/CSharpObfuscator/raw/main/img/cso.png?raw=true

something like this

Bernd Baumanns

@bernd5

I would avoid arabic chars

timiil

@timiil

Bernd Baumanns

@bernd5

I would name them a1, a2, a3....

but unicode should work, too.

or perhaps something like obf_local_1

timiil

@timiil

are not these task can be done by Analyzer??

Bernd Baumanns

@bernd5

no, an analyzer produces just diagnostic AFAIK

it would be a pre compile step

Yair Halberstadt

@YairHalberstadt

@VBAndCs that's basically what decompilers do - e.g. sharplab

timiil

@timiil

who produce the tons of 'Change Code Suggestion' in the vs ??

Bernd Baumanns

@bernd5

these are called "Code Fix"

timiil

@timiil

may be my missunderstanding that these are from roslyn

Bernd Baumanns

@bernd5

the are developed by the VS team

no they are from roslyn - that is right

timiil

@timiil

so , how can i write some anti human reading CodeFix rule ?

Bernd Baumanns

@bernd5

CodeFix is more than you need - a CodeFix adds some VS integration code

timiil

@timiil

oh, sounds bad. sounds that related by IDE, but not dotnet CLR

Bernd Baumanns

@bernd5

you could write a simple console app which loads the original source and produces "obfuscated" source which is than compiled to IL via the normal build pipeline

Yes, CodeFixes are IDE related - but what you want is not IDE related

timiil

@timiil

thanks for your kindly reply, a lot of knowlege knowed toninght and i should keep learning more

Bernd Baumanns

@bernd5

When you write your obfuscator you have to care about e.g. nameof() and reflection

because those names would change, too.

If you need further help - please ask.

timiil

@timiil

sure , very thanks :)

Yair Halberstadt

@YairHalberstadt

@timiil most obfuscators work with raw IL. They already exist so not sure why you would roll your own

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