Gotta check if it's needed here or not, might be unneeded. It's meant to be used with macros, as commas in angle brackets get treated as argument separators for surrounding macros, e.g.
```
MACRO(Foo<Bar, Baz> plugh)
```
is evaluated as `MACRO(arg1, arg2)` with `arg1 = Foo<Bar` and `arg2 = Baz> plugh`