Regardless of the presentation (a.k.a. syntax) the important thing is that programs should be described and generated in a controlled way. This is already done by the "Formal verification and mathematically proving" that is mentioned. You should not discard it only because of performance problems. If verification time is the problem, then your description of what you want is too ambitious. You should refine your requirement description to gain more generation/verification performance.
Regardless of the presentation (a.k.a. syntax) the important thing is that programs should be described and generated in a controlled way. This is already done by the "Formal verification and mathematically proving" that is mentioned. You should not discard it only because of performance problems. If verification time is the problem, then your description of what you want is too ambitious. You should refine your requirement description to gain more generation/verification performance.