Summary

Objective-C 2.0 grammars with preprocessor support can be used in 2 different modes:

• One-step processing. Includes a lexer which is used for both directives and ordinary Objective-C code. Used in Swiftify Objective-C to Swift converter.
• Two-step processing. Includes separate lexers for directives and Objective-C code. Used in Codebeat, the web service for automated code review for different programming languages (including Objective-C).

One-step processing

1. Lexer (ObjectiveCLexer.g4).
2. Parser (ObjectiveCPreprocessorParser.g4 and ObjectiveCParser.g4).

Two-step processing

1. Preprocessor lexer (ObjectiveCPreprocessorLexer.g4).
2. Preprocessor parser (ObjectiveCPreprocessorLexer.g4).
3. Visitor class for removing preprocessor directives from code (ObjectiveCPreprocessor.java).
4. Lexer (ObjectiveCLexer.g4).
5. Parser (ObjectiveCParser.g4).

ObjectiveCPreprocessor processes preprocessor directives and replaces code that does not compile with spaces. Spaces are kept for correct detection of error line and column numbers during parsing of the ordinary Objective-C code. ObjectiveCParser is shared by both one-step and two-step processing.

Testing

One-step processing

Successful parsing and conversion of complete projects, ex. Popovers demo.

Two-step processing

More than 95% correctly parsed .m files from these projects:

1. AFNetworking
2. realm-cocoa
3. iOS-Source-Code-Analyze
4. SDWebImage
5. MJRefresh
6. SmarterStreaming
7. ReactiveCocoa
8. GSKStretchyHeaderView
9. JSQMessagesViewController
10. SocketRocket
11. MBProgressHUD
12. DZNEmptyDataSet
13. AsyncDisplayKit
14. UITableView-FDTemplateLayoutCell3
15. SDAutoLayout
16. Chameleon
17. TomatoRead
18. iCarousel
19. SVProgressHUD
20. fmdb

License

ObjectiveC grammars and helper files are licensed under MIT.