I really like initiatives like Crystal and Nim, in that they appeal to users of popular languages like Ruby and Python yet are much faster. But I fear that the problem they solve isn't big enough. For desktop/mobile apps, they need a UI framework so I suppose they're targeted at web or network/system programming mostly. However, "Faster Ruby" or "Faster Python" is, in practice, solved by faster hardware as well. At t…
Then use FreePascal/Lazarus for your client. Don't know about the state of the mobile libs, but Delphi/FP perfected desktop UI development a long time ago. Decouple backend into whatever you want so you have an asset that is UI agnostic.