Sublime Text with GDL theme plus eventually GDL nucleus;
see: https://www.b-prisma.de/object-shop/index.php?cPath=10&MODsid=fa5254130320afdd8c5c04fc28716d19
and: https://www.youtube.com/watch?v=i7zEu4wtVvE
and: https://www.opengdl.org/Default.aspx?tabid=9748
GDL Object Developer
b-prisma
MAC OSx 10.14