cup

Cup is an excellent Vim plugin that delivers CUP syntax highlighting to your editing experience. Vim was developed by Bram Moolenaar in 1991, primarily for the Amiga computer. This powerful text editor was crafted as a more elaborate version of the vi editor, with multiple extra features capable of improving editing of programming source code. Vim is versatile, with cross-platform compatibility, and primarily popular in Unix-like operating systems. It is also free and open source software, released under a software license that's compatible with the GNU General Public License, with some charityware clauses included.

Vim’s user interface is based on text user interfaces, utilizing commands rather than menus or icons. However, its GUI mode (gVim) features menus and toolbars used for commonplace functionalities, but the full range of operations is still only available via its command-line mode. In the beginning, Vim can be hard and slow to comprehend. Still, once you master its basic functions and commands, your editing becomes more efficient. To simplify the process of learning vim, Vim offers a built-in tutorial for novices and a Vim Users' Manual, which provides more advanced Vim features in detail. This manual can be accessed within Vim or found online.

For users who seek it, Vim also provides a built-in help facility via the :help command, allowing users to navigate through commands and features. If you are looking for excellent syntax highlighting with CUP on Vim, Cup will undoubtedly be a great option.