This project actually uses Yosys. From a quick glance at the code, this tool essentially uses Yosys for the heavy-duty logic stuff [1], resulting in a JSON-based logic definition using a couple of standard cells (DFF, MUX, arithmetic, etc.) that verilog2factorio parses [2] and translates into predefined Factorio blueprints. The only part that I couldn't find would be laying out the cells into the overall blueprint (and performing routing).

[1] https://github.com/Redcrafter/verilog2factorio/blob/9691b702...

[2] https://github.com/Redcrafter/verilog2factorio/blob/9691b702...

You don't need much understanding in advance to develop a novel backend, since you are forced and guided to learn the whole language as you try to write the backend and start pattern matching on the data structures.

I think the apparent increase in Verilog popularity is due to pretty much all FOSS toolchains (i.e. mostly Yosys) only supporting Verilog [1], so most of the content publicly visible on blogs etc. uses Verilog.

And I guess the reason that most tooling focuses on Verilog is that the VHDL standard is a little bit of a mess from a parsing point of view. Essentially, in order to correctly parse some VHDL file A you first need to parse every other file that A might depend on. [2] Source: Tried writing a VHDL parser a few years ago.

[1] AFAIK you can buy a license for a VHDL frontend from one of the companies contributing to Yosys, but that's a different story.

[2] Example: What is f(1)? It could be a) calling a function called f with a parameter_association_list consisting of 1 or b) an indexed name, accessing an array called f at index 1, or c) some other things if we're not currently in an expression context. The only way to parse this correctly is to know what f is, but if f is not defined in the file you're currently parsing, there's no way to know other than parsing all other files...

VHDL/Verilog is a bit like Pascal/C division used to be, with VHDL having more fans in Europe and Verilog on US, and then the respective countries that do business with them.

At least that is how I understand the market division, it might also be that one of them has already won, not sure about that.