DEV Community: riscie

C# switch - Which variation do you prefer?

riscie — Thu, 12 Mar 2020 10:28:03 +0000

Let's say I have the following Enum:

public enum Cases
{
    One,
    Two,
    Three,
    Four,
    Five
}

And I would like to implement the following logic using switch:

One        => "one to three"
Two        => "one to three"
Three      => "one to three"
Four       => "four"
Five       => "five"
all others => throw an Exception

Before C# 8.0, I would have written my example using a classic switch statement:

Heads-up, if you don't know: [Theory] and [InlindeData] are Attributes used by xunit, a dotnet testing framework. You can ignore it, it's not important to the discussion I would like to initiate. (I had to make sure that my logic is correct, before we can discuss, right 😉)

[Theory]
[InlineData(Cases.One, "one to three")]
[InlineData(Cases.Two, "one to three")]
[InlineData(Cases.Three, "one to three")]
[InlineData(Cases.Four, "four")]
[InlineData(Cases.Five, "five")]
public void SwitchStatement(Cases? input, string expected)
{
    string actual;
    switch (input)
    {
        case Cases.One:
        case Cases.Two:
        case Cases.Three:
            actual = "one to three";
            break;
        case Cases.Four:
            actual = "four";
            break;
        case Cases.Five:
            actual = "five";
            break;
        default:
            throw new InvalidEnumArgumentException();
    }

    Assert.Equal(expected, actual);
}

With C# 8.0 we did get switch expressions. Now we could write it like so:

[Theory]
[InlineData(Cases.One, "one to three")]
[InlineData(Cases.Two, "one to three")]
[InlineData(Cases.Three, "one to three")]
[InlineData(Cases.Four, "four")]
[InlineData(Cases.Five, "five")]
public void SwitchExpression(Cases? input, string expected)
{
    var actual = input switch
    {
        Cases.One => "one to three",
        Cases.Two => "one to three",
        Cases.Three => "one to three",
        Cases.Four => "four",
        Cases.Five => "five",
        _ => throw new InvalidEnumArgumentException()
    };

    Assert.Equal(expected, actual);
}

Or we can also combine cases One, Two and Three using when:

[Theory]
[InlineData(Cases.One, "one to three")]
[InlineData(Cases.Two, "one to three")]
[InlineData(Cases.Three, "one to three")]
[InlineData(Cases.Four, "four")]
[InlineData(Cases.Five, "five")]
public void SwitchExpressionWhen(Cases input, string expected)
{
    var actual = input switch
    {
        var x when x == Cases.One || x == Cases.Two || x == Cases.Three => "one to three",
        Cases.Four => "four",
        Cases.Five => "five",
        _ => throw new InvalidEnumArgumentException()
    };

    Assert.Equal(expected, actual);
}

We could also combine 1 to 3 using when in a diffrent variation using an Array and Contains():

[Theory]
[InlineData(Cases.One, "one to three")]
[InlineData(Cases.Two, "one to three")]
[InlineData(Cases.Three, "one to three")]
[InlineData(Cases.Four, "four")]
[InlineData(Cases.Five, "five")]
public void SwitchExpressionContains(Cases input, string expected)
{
    var actual = input switch
    {
        var x when new[] {Cases.One, Cases.Two, Cases.Three}.Contains(x) => "one to three",
        Cases.Four => "four",
        Cases.Five => "five",
        _ => throw new InvalidEnumArgumentException()
    };

    Assert.Equal(expected, actual);
}

❔ Which one of the examples do you prefer? Which one is the most readable to you? Or do you have an even nicer variation to share?

📊 I would like to gather the results in a poll. Do you mind giving your vote?

M. Langhard

@langhard

C# switch - Which variation do you prefer?
dev.to/riscie/c-switc…

10:30 AM - 12 Mar 2020

0 0

Passing a parameter to a zsh keyboard-shortcut

riscie — Fri, 17 May 2019 09:25:02 +0000

Intro

This post follows up on my previous post Using keyboard-shortcuts with zsh. As promised I will show how we can pass an argument / string to a zsh keyboard-shortcut.

We could for example use this option to create git feature branches by doing:

[typing the name of the branch] --> [keyboard-shortcut] --> [done]

Show me the code!



# create a feature branch with <name> and then ctrl-g+f
function featbranch() {
    branch_name=$BUFFER
    zle backward-kill-line
    echo "git checkout -b feat/$branch_name"
    git checkout -b "feat/${branch_name}"
    zle reset-prompt
    zle redisplay
}
zle -N featbranch
bindkey '^gf' featbranch

A bit longer than our previous widget. Let's break it down line by line:

Another awesome comment
The function which will be executed by our keystroke:
Save the current terminal-line into a variable
Clear the current line
Display the full command we like to execute
Execute the command
Reset the prompt. (Useful if we display branch-information in our promt)
Redisplay our prompt.
Again we define a widget that points to the function
And bind our key-combination to the widget

So there we have it. Let me know if it works for you!

❤️ Let's connect!

I would love to grow my network with other tech enthusiasts. Let's connect here or over on twitter! 👋 @langhard

Resources

A User's Guide to the Z-Shell

What are your five most used terminal commands?

riscie — Wed, 15 May 2019 12:59:49 +0000

I start:

     1  1874  18.3942%     git
     2  709   6.95917%     sudo
     3  622   6.10522%     cd
     4  565   5.54574%     kubectl
     5  480   4.71143%     docker

I found this nice gem in the-book-of-secret-knowledge. (A good link for any terminal user. Have a look!)

show your top 5 most used commands including their usage %

history | \
awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | \
grep -v "./" | \
column -c3 -s " " -t | \
sort -nr | nl |  head -n 5

(the original was slightly modified to only show the top 5, instead of 20)

I tought it would be fun to share our most used commands here. Show me yours! ;)

❤️ Let's connect!

I would love to grow my network with other tech enthusiasts. Let's connect here or over on twitter! 👋 @langhard

Heads up

I mean I almost don't need to say this, but: Please have a close look at your commands before you share them, don't share private information!

Using keyboard-shortcuts with zsh

riscie — Tue, 14 May 2019 08:35:18 +0000

Are you a zsh user? Do you like to tweak your shell to the maxium in order to gain a bit of time here or there? You might be in the right place here.

This post will show you how to use keyboard shortcuts within zsh to run common commands.

git pull using a keyboard shortcut

In this example we want to run git pull with the shortcut ctrl-g+p (meaning ctrl-g - releasing g - pressing p) as seen in the gif above.

We define our shortcuts in the zsh ressource file. It's normally called .zshrc and we find it within our home directory. I use visual studio code to edit the file:

code ~/.zshrc

Add the following content to the file:

# git pull (ctrl-g+p)
function gitpull() { echo "git pull"; git pull; zle reset-prompt; zle redisplay}
zle -N gitpull
bindkey '^gp' gitpull

Lets break it down line-by-line

A nice comment
We define the function gitpull which we use for our keybinding later. The function does:
1. Write out the command we send. (I like this over having an empty screen doing something)
2. Runs git pull
3. Resets our prompt. (This is useful, if we have git information in our prompt, as they are not updated if we don't use reset-prompt)
4. Redisplays our prompt
We define a widget that points to the function
We bind our key-combination to the widget

That's it. Let me know if it works for you. If there is some interest in this kind of stuff, I could follow up with an example of how to pass an argument to a keyboard shortcut. I for example use this option to create feature branches by doing:

typing the name of the feature branch --> ctrl-g+f

Bonus

Some more shortcut definition examples also using alt as the modifier to get you started:

'^g'   # ctrl-g
'^gp'  # ctrl-g and then p (as shown in the example)
'^[x'  # alt-x
'^[xc' # alt-x and then c

❤️ Let's connect!

I would love to grow my network with other tech enthusiasts. Let's connect here or over on twitter! 👋 @langhard

Resources

A User's Guide to the Z-Shell

Update

Part 2 - Passing a parameter to a zsh keyboard-shortcut - is now online.