Some initial work can be found under Scripts/convert-nib-to-xib, which converts the WorldWideWeb.nib into a modern interface builder XIB.

Progress

• Translate the main menu to XIB (partially done)
  • Find the main menu in the NIB and create corresponding menus in the XIB
  • Rearrange the menus to match macOS conventions (e.g. no items without submenus in the main menu bar)
  • Translate keyboard shortcuts
• Translate the connectors
  • Translate action/control connectors
  • Translate outlet connectors
• Translate the windows to XIB
  • Translate the top-level windows itself
  • Translate more relevant metadata aside from title and geometry
• Translate the widgets to XIB
  • Translate generic views
  • Translate boxes
  • Translate buttons
  • Translate text fields
  • Translate scroll views and clip views
  • Translate forms (may require more testing if there's something in the form cells we missed)
  • Translate text
    • Translate RTF to attributed strings
  • Translate images
    • See https://www.nextop.de/NeXTstep_3.3_Developer_Documentation/GeneralRef/_ApD_SystemBitmaps/SysBitmaps.htmld/index.html
  • Translate matrices
• Translate fonts
• Fix the outlets/actions in the code

Even with the relatively simple translation that almost exclusively takes text and frames (position/size) into account, we already get a pretty decently recognizable UI:

Compared to the 90s NeXT version, this doesn't look too far off:

Implementation notes

• The Reference folder contains some useful demo files for reverse engineering the format:
  • Minimal*.xib are simple valid XIBs, generated by Xcode, with and without a main window
  • WorldWideWeb.{json,xml} is a direct JSON/XML dump of the data in the legacy NIB, generated by the respective convert-nib-to-{json,xml} scripts
• Generally, it seems to be helpful to dig through the WorldWideWeb.xml looking for entry points (e.g. MainMenu) and then trace the object references from there
• The "group structure" of classes is generally fixed, so we can hardcode indices once we find something interesting (such as a menu title or a submenu)
• The object graph may contain backreferences, so we'll have to keep track of visited objects
• A neat trick to find the syntax for a particular XIB element (aside from adding the element in interface builder and observing how the XML changes) is to use GitHub's Code Search e.g. https://github.com/search?q=path%3A**%2F*.xib+%3CtextView&type=code

Web resources

• Legacy NIB format (NextSTEP)
  • https://ftp.nice.ch/pub/next/tools/hack/_NibList.README.html
• Legacy XIB format
  • Docs: http://www.monobjc.net/xib-file-format.html
  • Real-world examples:
    • https://opensource.apple.com/source/Security/Security-55471.14.8/Keychain%20Circle%20Notification/en.lproj/MainMenu.xib.auto.html
    • https://android.googlesource.com/platform/external/chromium_org/+/refs/heads/main/chrome/app/nibs/DownloadItem.xib
• Modern XIB format
  • A minimal XIB file: https://gist.github.com/leiless/fec555e0b83b6d48722227e27825fc00
  • Our MainMenu.xib: https://github.com/fwcd/worldwideweb-cocoa/blob/main/WorldWideWeb/Base.lproj/MainMenu.xib