[gcc r14-7417] gccrs: ast: Add trailing comma formatting option

[Arthur Cohen]

https://gcc.gnu.org/g:06dcc5fdf4d72e4c43beb1a2eb3376c4e252e1f4

commit r14-7417-g06dcc5fdf4d72e4c43beb1a2eb3376c4e252e1f4
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Wed Mar 22 14:39:34 2023 +0100

    gccrs: ast: Add trailing comma formatting option
    
    Add an option to output trailing commas depending on the configuration
    of the TokenStream.
    
    gcc/rust/ChangeLog:
    
            * ast/rust-ast-tokenstream.cc (TokenStream::trailing_comma):
            Output a trailing comma to the token stream according to the
            configuration.
            * ast/rust-ast-tokenstream.h: Add function prototype.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/ast/rust-ast-tokenstream.cc | 9 +++++++++
 gcc/rust/ast/rust-ast-tokenstream.h  | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/gcc/rust/ast/rust-ast-tokenstream.cc b/gcc/rust/ast/rust-ast-tokenstream.cc
index a7fee13a1ae..d68c19a44fe 100644
--- a/gcc/rust/ast/rust-ast-tokenstream.cc
+++ b/gcc/rust/ast/rust-ast-tokenstream.cc
@@ -92,6 +92,15 @@ TokenStream::visit_items_as_block (T &collection,
   tokens.push_back (Rust::Token::make (right_brace, Location ()));
 }
 
+void
+TokenStream::trailing_comma ()
+{
+  if (output_trailing_commas)
+    {
+      tokens.push_back (Rust::Token::make (COMMA, Location ()));
+    }
+}
+
 void
 TokenStream::visit (FunctionParam &param)
 {
diff --git a/gcc/rust/ast/rust-ast-tokenstream.h b/gcc/rust/ast/rust-ast-tokenstream.h
index 70ef24637ff..58459c6317a 100644
--- a/gcc/rust/ast/rust-ast-tokenstream.h
+++ b/gcc/rust/ast/rust-ast-tokenstream.h
@@ -31,6 +31,7 @@ class TokenStream : public ASTVisitor
 {
 public:
   TokenStream (std::vector<TokenPtr> &container);
+  bool output_trailing_commas = false;
 
   void go (AST::Crate &crate);
   void go (AST::Item &item);
@@ -86,6 +87,7 @@ private:
 			     TokenId left_brace = LEFT_CURLY,
 			     TokenId right_brace = RIGHT_CURLY);
 
+  void trailing_comma ();
   /**
    * Visit common items of functions: Parameters, return type, block
    */