Scott Hanselman

Tabs vs Spaces - A peaceful resolution with EditorConfig in Visual Studio. Plus .NET Extensions!

September 28, '17 Comments [23] Posted in VS2017
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The culture wars continue. The country is divided with no end in sight. Tabs or spaces? There's even an insane (IMHO) assertion that the spaces people make more money.

I'm going with Gina Trapani on this one. I choose working code.

Teams can fight but the problem of formatting code across teams is solved by EditorConfig. I'm surprised more people don't know about it and use it, so this blog post is my small way of getting the word out. TELL THE PEOPLE.

Take a project and make a new .editorconfig file and put this in it. I'll use a dotnet new console example hello world app.

[*.cs]
indent_style = tab
indent_size = tab
tab_size = 4

I've set mine in this example to just *.cs, but you could also say [*.{cs,js}] or just [*] if you like, as well as have multiple sections.

You'll check this file in WITH your project so that everyone on the team shares the team's values.

Here in Notepad2 we can see someone has used spaces for whitespace, like a savage. Whitespace appears as pale dots in this editor.

image

I'll open this project in Visual Studio 2017 which supports the EditorConfig file natively. Notice the warning at the bottom where VS lets me know that this project has conventions that are different than my own.

user preferences for this file type are overwidden by this project's coding conventions

VS Format Document commands will use tabs rather than spaces for this project. Here is the same doc reformatted in VS:

image

At this point I'm comforted that the spaces have been defeated and that cooler heads have prevailed - at least for this project.

.NET Extensions to EditorConfig

Even better, if your editor supports it, you can include "EditorConfig Extensions" for specific files or languages. This way your team can keep things consistent across projects. If you're familiar with FxCop and StyleCop, this is like those.

There's a ton of great .NET EditorConfig options you can set to ensure the team uses consistent Language Conventions, Naming Conventions, and Formatting Rules.

  • Language Conventions are rules pertaining to the C# or Visual Basic language, for example, var/explicit type, use expression-bodied member.
  • Formatting Rules are rules regarding the layout and structure of your code in order to make it easier to read, for example, Allman braces, spaces in control blocks.
  • Naming Conventions are rules respecting the way objects are named, for example, async methods must end in "Async".

You can also set the importance of these rules with things like "suggestion," or "warning," or even "error."

As an example, I'll set that my team wants predefined types for locals:

dotnet_style_predefined_type_for_locals_parameters_members = true:error

Visual Studio here puts up a lightbulb and the suggested fix because my team would rather I use "string" than the full "System.String.

Visual Studio respects EditorConfig

The excellent editorconfig for .NET docs have a LOT of great options you can use or ignore. Here's just a FEW (controversial) examples:

  • csharp_new_line_before_open_brace - Do we put open braces at the end of a line, or on their own new line?
  • csharp_new_line_before_members_in_object_initializers - Do we allow A = 3, B = 4, for insist on a new line for each?
  • csharp_indent_case_contents - Do we freakishly line up all our switch/case statements, or do we indent each case like the creator intended?
  • You can even decide on how you Want To Case Things And Oddly Do Sentence Case: pascal_case, camel_case, first_word_upper, all_upper, all_lower

If you're using Visual Studios 2010, 2012, 2013, or 2015, fear not. There's at least a basic EditorConfig free extension for you that enforces the basic rules. There is also an extension for Visual Studio Code to support EditorConfig files that takes just seconds to install although I don't see a C# one for now, just one for whitespace.


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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The Book of the Runtime - The internals of the .NET Runtime that you won't find in the documentation

September 27, '17 Comments [6] Posted in DotNetCore
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The Microsoft Docs at https://docs.microsoft.com are really fantastic lately. All the .NET Docs are on GitHub https://github.com/dotnet/docs/ and you can contribute to them. However, in the world of software engineering (here some a bad, mixed metaphor) there's instructions on how to use a faucet and there's instructions on how to build and design plumbing from scratch.

RyuJIT High level overview

There's additional DEEP docs that don't really belong on the docs site. It's the Book of the Runtime and for now it's on GitHub. Here's the BotR FAQ.

If you're interested in the internals of a system like the .NET Runtime, these docs are a gold mine for you.

The Book of the Runtime is a set of documents that describe components in the CLR and BCL. They are intended to focus more on architecture and invariants and not an annotated description of the codebase.

It was originally created within Microsoft in ~ 2007, including this document. Developers were responsible to document their feature areas. This helped new devs joining the team and also helped share the product architecture across the team.

We realized that the BotR is even more valuable now, with CoreCLR being open source on GitHub. We are publishing BotR chapters to help a new set of CLR developers.

This book likely isn't for you if you're an app developer. Who is it for?

  • Developers who are working on bugs that impinge on an area and need a high level overview of the component.
  • Developers working on new features with dependencies on a component need to know enough about it to ensure the new feature will interact correctly with existing components.
  • New developers need this chapter to maintain a given component.

These aren't design documents, these are docs that were written after features are implemented in order to explain how they work in practice.

Recently Carol Eidt wrote an amazing walkthrough to .NET Core's JIT engine. Perhaps start at the JIT Overview and move to the deeper walkthrough. Both are HUGELY detailed and a fascinating read if you're interested in how .NET makes Dynamic Code Execution near-native speed with the RyuJIT - the next-gen Just in Time compiler.

Here's a few highlights I enjoyed but you should read the whole thing yourself. It covers the high level phases and then digs deeper into the responsibilities of each. You also get a sense of why the RyuJIT is NOT the same JITter from 15+ years ago - both the problem space and processors have changed.

This is the 10,000 foot view of RyuJIT. It takes in MSIL (aka CIL) in the form of byte codes, and the Importer phase transforms these to the intermediate representation used in the JIT. The IR operations are called “GenTrees”, as in “trees for code generation”. This format is preserved across the bulk of the JIT, with some changes in form and invariants along the way. Eventually, the code generator produces a low-level intermediate called InstrDescs, which simply capture the instruction encodings while the final mappings are done to produce the actual native code and associated tables.

ryujit-phase-diagram

This is just one single comprehensive doc in a collection of documents. As for the rest of the Book of the Runtime, here's the ToC as of today, but there may be new docs in the repository as it's a living book.

Check it out!


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Spend less time CD'ing around directories with the PowerShell Z shortcut

September 24, '17 Comments [18] Posted in PowerShell
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Everyone has a trick for moving around their computer faster. It might be a favorite shell, a series of aliases or shortcuts. I like using popd and pushd to quickly go deep into a directory structure and return exactly where I was.

Another fantastic utility is simply called "Z." There is a shell script for Z at https://github.com/rupa/z that's for *nix, and there's a PowerShell Z command (a fork of the original) at https://github.com/vincpa/z.

As you move around your machine at the command line, Z is adding the directories you usually visit to a file, then using that file to give you instant autocomplete so you can get back there FAST.

If you have Windows 10, you can install Z in seconds like this:

C:\> Install-Module z -AllowClobber

Then just add "Import-Module z" to the end of your Profile, usually at $env:USERPROFILE\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1

Even better, Z works with pushd, cd, or just "z c:\users\scott" if you like. All those directory changes and moves will be recorded it the Z datafile that is stored in ~\.cdHistory.

What do you think? Do you have a favorite way to move around your file system at the command line?


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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What would a cross-platform .NET UI Framework look like? Exploring Avalonia

September 21, '17 Comments [28] Posted in Open Source | WPF
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Many years ago before WPF was the "Windows Presentation Foundation" and introduced XAML as a UI markup language for .NET, Windows, and more, there was a project codenamed "Avalon." Avalon was WPF's codename. XAML is everywhere now, and the XAML Standard is a vocabulary specification.

Avalonia is an open source project that clearly takes its inspiration from Avalon and has an unapologetic love for XAML. Steven Kirk (GitHubber by day) and a team of nearly 50 contributors are asking what would a cross-platform .NET UI Framework look like. WPF without the W, if you will.

Avalonia (formerly known as Perspex) is a multi-platform .NET UI framework. It can run on Windows, Linux, Mac OS X, iOS and Android.

YOU can try out the latest build of Avalonia available for download here:https://ci.appveyor.com/project/AvaloniaUI/Avalonia/branch/master/artifacts and probably get the "ControlCatalog.Desktop" zip file at the bottom. It includes a complete running sample app that will let you explore the available controls.

Avalonia is cross-platform XAML ZOMG

It's important note that while Avalonia may smell like WPF, it's not WPF. It's not cross-platform WPF - it's Avalonia. Make sense? Avalonia does styles differently than WPF, and actually has a lot of subtle but significant syntax improvements.

Avalonia is a multi-platform windowing toolkit - somewhat like WPF - that is intended to be multi- platform. It supports XAML, lookless controls and a flexible styling system, and runs on Windows using Direct2D and other operating systems using Gtk & Cairo.

It's in an alpha state but there's an active community excited about it and there's even a Visual Studio Extension (VSIX) to help you get File | New Project support and create an app fast. You can check out the source for the sample apps here https://github.com/AvaloniaUI/Avalonia/tree/master/samples.

Just in the last few weeks you can see commits as they explore what a Linux-based .NET Core UI app would look like.

You can get an idea of what can be done with a framework like this by taking a look at how someone forked the MSBuildStructuredLog utility and ported it to Avalonia - making it cross-platform - in just hours. You can see a video of the port in action on Twitter. There is also a cross-platform REST client you can use to call your HTTP Web APIs at https://github.com/x2bool/restofus written with Avalonia.

The project is active but also short on documentation. I'm SURE that they'd love to hear from you on Twitter or in the issues on GitHub. Perhaps you could start contributing to open source and help Avalonia out!

What do you think?


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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A Functional Web with ASP.NET Core and F#'s Giraffe

September 18, '17 Comments [11] Posted in DotNetCore
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728331198_7c1854e363_bI was watching Ody Mbegbu's YouTube Channel - it's filled with .NET Core and ASP.NET Tutorial Videos - and was checking out one in particular, "Getting Started with ASP.NET Core Giraffe." Dane Vinson pointed me to it.

There is such a great open source renaissance happening right now with new framework's and libraries popping up in the .NET Core space. I hope you check them out AND support the creators by getting involved, writing docs, filing (kind) issues, and even doing pull requests and fixing bugs or writing tests.

Ody's video was about Dustin Morris' "Giraffe" web framework. Dustin's description is "A native functional ASP.NET Core web framework for F# developers." You can check it out over at https://github.com/dustinmoris/Giraffe.

Even better, it uses the "dotnet new" templating system so you can check it out and get started in seconds.

c:> md \mygiraffeeapp & cd \mygiraffeeapp
c:\mygiraffeeapp> dotnet new -i "giraffe-template::*"
c:\mygiraffeeapp> dotnet new giraffe
The template "Giraffe Web App" was created successfully.
c:\mygiraffeeapp> dotnet run
Hosting environment: Production
Content root path: C:\mygiraffeapp
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

Boom. Now I'm checking out Giraffe's "Hello World."

Because ASP.NET Core is very modular and built on "middleware" pipelines, that means that other frameworks like Giraffe can use the bits they want and remove the bits they down. Remembering that this is F#, not C#, here you can see Giraffe adding itself to the pipeline while still using the StaticFileMiddleware.

let configureApp (app : IApplicationBuilder) =
app.UseGiraffeErrorHandler errorHandler
app.UseStaticFiles() |> ignore
app.UseGiraffe webApp

The initial readme.md for Giraffe is the docs for now, and frankly, they are excellent and easy to read. The author says:

It is not designed to be a competing web product which can be run standalone like NancyFx or Suave, but rather a lean micro framework which aims to complement ASP.NET Core where it comes short for functional developers. The fundamental idea is to build on top of the strong foundation of ASP.NET Core and re-use existing ASP.NET Core building blocks so F# developers can benefit from both worlds.

Here is a smaller Hello World. Note the use of choose and the clear and terse nature of F#:

open Giraffe.HttpHandlers
open Giraffe.Middleware

let webApp =
choose [
route "/ping" >=> text "pong"
route "/" >=> htmlFile "/pages/index.html" ]

type Startup() =
member __.Configure (app : IApplicationBuilder)
(env : IHostingEnvironment)
(loggerFactory : ILoggerFactory) =

app.UseGiraffe webApp

Is terse an insult? Absolutely not, it's a feature! Check out this single line exampe...and the fish >=> operator! Some people don't like it but I think it's clever.

let app = route "/" >=> setStatusCode 200 >=> text "Hello World"

Making more complex:

let app =
choose [
GET >=> route "/foo" >=> text "GET Foo"
POST >=> route "/foo" >=> text "POST Foo"
route "/bar" >=> text "Always Bar"
]

Or requiring certain headers:

let app =
mustAccept [ "text/plain"; "application/json" ] >=>
choose [
route "/foo" >=> text "Foo"
route "/bar" >=> json "Bar"
]

And you can continue to use Razor views as you like, passing in models written in F#

open Giraffe.Razor.HttpHandlers

let model = { WelcomeText = "Hello World" }

let app =
choose [
// Assuming there is a view called "Index.cshtml"
route "/" >=> razorHtmlView "Index" model
]

There are samples at https://github.com/dustinmoris/Giraffe/tree/master/samples you can check out as well

* Giraffe photo by Kurt Thomas Hunt, used under CC


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Disclaimer: The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.