Math parsing libraries can be extremely useful whenever you want to evaluate a complex mathematical expression. In Objective-C you can use NSPredicate. If you want to extend the functionality of NSPredicate however, this can be extremely difficult.
I came across a math parser that provides many advantages over NSPredicate, and other existing math libraries with in my opinion the key feature being the ease at which you can register new functions.
The library is DDMathParser from DaveDeLong. The Github for the library can be found here:
You can also read Dave’s extensive writeup on the library on his website here:
Parsing Mathematical Expressions
There are many other advantages of using Dave’s library over NSPredicate and other existing math parser’s in his writeup.
Looks like the right choice if you need to go beyond the default functionality provided by NSPredicate.
The Core Text library allows for easy text formatting and I have mentioned it several times in the past with the fancy text effects tutorial and an excellent open source project enabling easy multi-column text display.
I’ve come across an excellent tutorial that puts everything together demonstrating how to create a magazine style app. You’ll learn how to format the text in multiple columns, justify, place images within your text, create fancy headlines and more.
What I really like about this tutorial is that it gives a high level overview of the Core Text module, and explains why and when you would want to use core text rather than a UIWebView and does so with a code example that you can actually use and create an app with.
The tutorial is from Marin Todorov and can be found here:
How To Create A Simple Magazine App With Core Text
A great tutorial and source code example if you ever need to create any kind of an app with formatted text.