cyrilbarthelet / chromatism

Obj-C Syntax Highlighting for iOS

Chromatism

This is the beginning of a syntax highlighting UITextView for iOS. Currently it only knows about Obj-C. Previously Chromatism used a combination of CoreText and UITableView for performance, but luckily that is not needed anymore.

Chromatism is currently unstable, changing quickly and without test-coverage.

License

MIT, see LICENSE.txt. If you develop Chromatism further, sharing your improvements are encouraged.

How to add Chromatism to your application:

1. Drag and drop Chromatism.xcodeproj to your project.
2. Add Chromatism as a target dependency and link to libChromatism.a
3. Make sure you have the -ObjC flag on the Other Linker Flags build setting.
4. Add "$(BUILT_PRODUCTS_DIR)/../../Headers" to the Header Search Paths build setting.

Classes

• JLTextView is a textView with a syntaxTokenixer property to a JLTokenizer
• JLTokenizer is the work horse of Chromatism. It uses scopes and tokenPatterns to appropriately tokenize a textStorage or a string. It is a delegate of NSTextStorage and UITextView.
• JLScope has a NSMutableIndexSet-property that corresponds to ranges in the textStorage. Scopes can be arranged in a hierarchy. A scope's children is stored in the subscopes property, and a scopes parent is simply called its scope. A scope can be executed via the -perform-method. The method causes subscopes to perform cascadingly.
• JLTokenPattern is a subclass of JLScope. It has a regex-pattern that in -perform searches through the ranges of its parent scope.

Scopes and Patterns

Scopes and patters can ensure that regex patterns search in the right place. To understand how they work, it is helpful to know what happens in the -perform method.

1. A scope may contain ranges before it's performed. When it's performed, the scope's set is intersected with the parent scope set. A scope can never contain more indexes that its parent scope.
2. The scope calls perform on its subscopes.
3. The scope ensures that its siblings don't search where the scope have found things.

For more detail, see the -perform-implementation on JLScope and JLTokenPattern.