Custom language that compiles to C - integrating and debugging

I'm looking at language that "compiles" to C. It's called Nim -- http://nim-lang.org/

The higher level "nim" code files might contain, for example:

var x: int=2
block block1:
  echo "Hello", x, " more" & " stuff"

My ultimate goal, if possible, is to use the VS toolchain to compile the C code (which is generated by the Nim compiler), and customize the VS debugger so that breakpoints are hit in the Nim code, and the C code is hidden or otherwise suppressed.

The C code will include line directives:
https://msdn.microsoft.com/en-us/library/b5w2czay.aspx

So I can sort-of do the above manually, and I can sort-of get there with GDB.

I realize I would have to figure out some way of displaying variables, watches, etc. I'm more interested in whether I can get even close to using the debugger in this way. I'd appreciate any samples or pointers. Thanks!