Sometimes you want to tell somebody how you fixed a problem in their code, but for some reason the code is not on github so you cannot send them a pull request. If you felt really smart then you might put the changes you made into an e-mail, like “in file1.m:102 you change it to x, in file2.m:54 you make change y”. Thought this doesn’t really help the developer you are trying to help. Even when following your change instructions to the letter it is a tedious and error-prone method of applying your changes. Thanks to M. Douglas McIlroy, Adjunct Professor at Dartmouth Colleague – one of the early Unix pioneers – there is a better way. He invented the form of diff that we are using today to get the Difference between two versions of a file. And Larry Wall who invented the patch command which can take a diff file and effectively apply it to files. Read more
Robert Meraner asks:
“Do you have any idea why this code works in iOS 4.3, but no longer under iOS 5? Googling it seems to turn up some ideas, but no immediate explanation.”
This is the code Robert refers to:
NSString *currentElementValue = @"01.12.2011 09:35:13 CET"; NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"dd.MM.yyyy HH:mm:ss zzz"]; NSDate *date = [dateFormatter dateFromString:currentElementValue];
This got me confounded initially as well, but thanks to Cédric Luthi we got an official answer to this riddle: works as intended!
Apple owns patent US5946647 and slapped that around HTC’s team of lawyers successfully. Apple has previously sued HTC over them infringing 4 of their patents seeking to block sales of several Android-based mobile phones that HTC is making. On December 19th the International Trade Commission published their final determination as to the validity of two claims in this patent while finding no infringement on the others.
This result is interesting for us iOS developers for several reasons. For one it shows that something we are taking for granted was actually patented by Apple. They filed it on February 1st, 1996 and the patent was granted 3 years later on August 31, 1999. Usually patents are very elusive and it is generally hard to show how a device or operating system really infringes upon them. But in this rare specimen Apple has the rights on something that you probably see every day.
Joseph Collins asks:
How do you decipher a bit mask from an argument which logically OR’d multiple values together? Enum uses bit shifting.
This question came to me while looking at UIView’s header file and wondering how Apple handles the animation options bitmask.
If you have several modes of something then usually you get by with an emum. But if you can combine several flags in s single value then you have to do this by means of bit masks. Let’s explore these today.
BinPress had custom-built an internal microsite for us judges where we could download the source code and fill in a form with our judgements. That allowed me to go into the components I was assigned to and really dig into the implementation details. Sorry, but I need to be wagging my finger here, all of the ones I saw had terrible form, little to no code style, the project setup generally was a mess and documentation non-existent.
But nevertheless a ranking was possible – especially because there where other equally important judging factors besides code quality. And so the shining winners are …
Honestly I was very much excited when I found that I can use my current knowledge of Objective-C and Foundation classes like NSString to also build nifty little tools. Previously I had to resort to bash script to perform one-off operations on files that where too tedious to do manually. But knowing what I am going to show you in this article will enable you to also write these littler helpers.
I believe that beginners should rather start with writing a couple of command line tools before diving into building user interface driven apps. Commend line tools are linear and thus their function is easier to grasp. They are more akin to “functional programming” then “object oriented programming” if you will.
I am going to show you what goes into building a simple command line tool and you be the judge whether you agree with my assessment.
The second hot fix pack for Linguan 1.0 fixes a couple more issues that some of our (mostly) happy customers reported.
- Fixed: Translations will no longer get trimmed
- Fixed: Problem opening projects with absolute file paths
- Fixed: Table did not update on deletion of token
- Changed: Extended duration of “no new tokens found” HUD
- Changed: Enter key now opens selected recent project in welcome screen
If you haven’t done so please post your feedback on iTunes. To be able to add additional features to Linguan we need to have sufficient sales. And for that we need your positive reviews, high rating and that you tell other developers about Linguan.
Today is the best day for them to also get a copy because: As a Thank You for your interest in our app we reduced the sale price by 50% until the new version gets approval by Apple.
I’m looking at your (nice) project NSAttributedString-Additions-for-HTML and I have some questions about your convention of writing code.
I really hope that you can reply to me, and maybe can be an idea for a future blog post (on naming conventions, and conventions in general for objective-c).
Though it is good practice to reflect on your style every once in a while to see if it still serves the purpose of making your code easier to maintain and read.
A very interesting yet very undocumented functionality of Xcode is that you can have sub-projects in your project tree. You can add an xcodeproj to your project and link to this project’s output.
This is exceptionally useful if you are developing some functionality in a contained project and now want to access this polished functionality from another project. Like for example you want to add to your app the capability of accepting HTML code copied from Safari and use my DTWebArchive classes for that. You could either copy all classes to your project, build two libraries (one for Simulator and one for Device, or lipo these two together), or build a static universal framework.
Or there is an option number 4 which I want to tell you about in this post. This option does neither copy source code nor does it involve building something upfront.
I know I know, Documentation is a bad bad word, especially for us creative people. The true creativity is in writing code, not in writing comments, isn’t it?
Well, regardless, you might find yourself in the situation that you want other people to reuse your code. Or better yet, a different self of you in a year should be able to understand your line of reasoning of today. If you do programming for a longer time you will pass the phase of being shocked at how bad your code was and then get into the phase of having no idea what you where thinking. So a liberal sprinkling of comments can help you get up to speed on your old code.
I invented a technique of chewing on a portion of a programming puzzle where you comment almost every line of code as if you were to explain to somebody the steps in your ingenious approach. Maybe somebody else coined a term for this, for me it helps me sort my thoughts. And probably will do the same a year or ten from now. So commenting comes naturally to me, Documentation by Comment-ation is a logical extension to the concept.