PSS DSL (Portable Stimulus Specification domain-specific language) syntax for Sublime Text 3+4. It supports highlighting of embedded C-code in exec blocks.
Place the syntax files somewhere in the Packages directory of Sublime. Check View->Syntax, an entry "PSS" should be there. If not, check View -> Show Console for errors.
Go to Preferences -> Package Control, "Install Package" and search for "PSS"
PSS 2.0 specification, see also https://www.accellera.org/activities/working-groups/portable-stimulus/
