[PATCH] D102579: [Demangle][Rust] Parse tuples

[Tomasz Miąsko via Phabricator via llvm-commits]

tmiasko added inline comments.


================
Comment at: llvm/lib/Demangle/RustDemangle.cpp:450-451
+    }
+    if (I == 1)
+      print(",");
+    print(")");
----------------
dblaikie wrote:
> tmiasko wrote:
> > dblaikie wrote:
> > > Looks a bit awkward to print a comma after a single argument (`(_,)`) - is that necessary? (does it disambiguate this with some other case that has only a list of 1 between parentheses?)
> > The intention is to match Rust language syntax which requires a comma after one element tuples to disambiguate them from parenthesized types.
> Cool - thanks for the context!
> 
> And stylistically, that trailing comma is usually written without a space after it, unlike separating commas?
> 
> Pity, this could come out more naturally from the algorithm if that was the case (always printing ", " after every type - rather than having to special case)
> 
> I guess you could do it this way:
> ```
> for (...) {
>   if (I > 0)
>     print(" ");
>   demangleType();
>   print(",");
> }
> ```
> Marginally less special casing
Looking at rustfmt, rustc type printer and other demanglers, they are consistent writing trailing comma without a space. They also include the trailing comma only when necessary, i.e., for one element tuple only (so I retained the special case).


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102579/new/

https://reviews.llvm.org/D102579