The claim is often made that languages like Forth and Scheme are better for building applications than less elegant and orthogonal languages. But the evidence on the ground is overwhelmingly to the contrary. The vast majority of commercially significant apps are built in relatively baroque and ugly languages like Java and C++.
Personally I think that the ability to define your own language constructs is ultimately a lot less useful than things like rich libraries and robust tooling and I'm still waiting to see real-world proof of the advantages of programmable programming languages.
Personally I think that the ability to define your own language constructs is ultimately a lot less useful than things like rich libraries and robust tooling and I'm still waiting to see real-world proof of the advantages of programmable programming languages.