VimR
Neovim GUI for macOS in Swift
...We mainly use Swift, but also use C/Objective-C when where appropriate. Markdown preview, generic HTML preview (retains the scroll position when reloading), fuzzy file finder a la Xcode's "Open Quickly". Trackpad support, pinching for zooming and two-finger scrolling. Ligatures, turned off by default. Turn it on in the Preferences. Command line tool, (Simple) file browser. Flexible workspace model a la JetBrain's IDEs.