jonny – Page 3 – Johannes Neubauer

Lazy Recursive Drill-Down of Tree Structures in Swift 2.1

11. January 201611. January 2016 jonny Leave a comment

I really do like the Swift programming language, because of features like multiple return types, nice support for optionals, value types (i.e., structs), enums with associated values, method overloading just with the return type, operator overloading, and many more.

But there are some language decision that are quite alien to me and I want to write them down (and my workarounds to them, which might help you), starting with this post. Perhaps you (yes I mean you 🙂 ) have a better answer for me, then please comment.
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LaTeX: replacing “-quotation marks with \glqq{} and \grqq{} in vim

12. February 201512. February 2015 jonny 2 Comments

If you ever had the problem that your LaTeX document contains wrongly formatted quotation marks (either in a german or english text), you most likely went all the way through your document searching for quotation marks and replacing them accordingly. Here are easy vim commands using the substitution feature (similar to the unix sed command) to replace all occurrences of quotation marks with the correct replacement for english texts:

:0,$s/\(\s\)"/\1``/g

:0,$s/\(\S\)"/\1''/g

And this one for german texts:

:0,$s/\(\s\)"/\1\\glqq{}/g

:0,$s/\(\S\)"/\1\\grqq{}/g

Exciting.

Apple Swift: Emulate Partial Fully Applied Functions

27. August 201427. August 2014 jonny Leave a comment

This article is only a short one, that tells an obvious fact, but I love it; hence, I will let you participate. Currently, I am doing a project with the new language Swift from Apple. Swift is a object-functional language like e.g. Scala.

Both languages have the nice functionality partial application of functions. This means you can set some of the parameters which returns a function that has the remaining parameters, only. So, it is not yet executed, but the already passed parameters are stored into the partial applied function and used if it is called with the rest of the parameters. Just for the seek of completeness, currying is then, when a function with multiple parameters is decomposed into a chain of functions that each has exactly one parameter (this is not the same).

But hey, this should be a short one. Here comes the punch line: You can partially apply functions, so that they have only one parameter, but what if I would like to preset all the parameters? It is very simple: Use a closure to create a new anonymous function, that simply executes the function of interest with all its parameters.
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Realize a Product Line with Tapestry 5

19. August 201419. August 2014 jonny Leave a comment

In this article about how to track the logins and logouts of users the AppModule has been used to add some configuration to a Tapestry application. The current article is about adding a product line to a Tapestry application in terms of localized message strings dependent on the language as well as the chosen product. The corresponding project may be found on github.
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Removing a whole bunch of commits from git

29. July 201429. July 2014 jonny Leave a comment

Imagine you have a repository for some time and then decide to publish it to someone (e.g. make it open source). The first n commits are garbage or contain content, that you do not want to share with others. So how do we get rid of these commits? Here we go.
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VirtualBox v4.2.18 with Native Hard Drive Partition in Mac OSX Lion

4. October 20134. October 2013 jonny Leave a comment

Most of the time you use desktop virtualization, you simply add a virtual hard drive and install a guest operating system (like (K)Ubuntu Linux) in it. But some times – as in my case – you already have another operation system on a partition on your native hard drive. For a mac it’s either via Bootcamp or via something like rEfit enabling you to install a BIOS boot manager like Grub. Since it is kind of uncommon using such an existing partition for desktop virtualization, it is not supported (and documented) so good in the different virtualization solutions.
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Uninstall VirtualBox Guest Additions on a Linux Guest OS

2. October 20132. October 2013 jonny Leave a comment

If you’d like to port a virtual machine from VirtualBox e.g. to parallels, you need to uninstall the guest additions. This is how it works:

sudo /opt/VBoxGuestAdditions-${version}/uninstall.sh

Trouble with Black Screen in Parallels Desktop v9 with Linux Guest OS on Native Partition

2. October 20132. October 2013 jonny Leave a comment

This post is a follow up to Using Parallels Desktop v9 with Linux Guest OS in a Native Partition. After the successful utilization of an existing Linux installation in Parallels Desktop v9 you might want to install the Parallel Tools, in order to have a much nicer integration of the guest system.

But I had the problem, that right after installing the Parallel Tools for Linux AMD 64: The screen went black after the login, when the video driver had been loaded. So I uninstalled the parallel tools again and uninstalled all nvidia drivers which I had installed for dual boot use. Afterwards I reinstalled parallel tools and everything was fine.

Using Parallels Desktop v9 with Linux Guest OS in a Native Partition

2. October 20132. October 2013 jonny Leave a comment

HowTo Word Break Type-Writer in LaTeX

30. January 201330. January 2013 jonny Leave a comment

By default LaTeX does not insert word breaks in type writer fonts, because the font has no dedicated character for hyphenations. But you can set the ‘-‘ as the corresponding character:

% line breaks in tt fonts
\newcommand{\origttfamily}{}
\let\origttfamily=\ttfamily
\renewcommand{\ttfamily}{\origttfamily \hyphenchar\font=`\-}