Merge #608

608: Add `parse_items()` function from `parse_crate()` r=philberty a=CohenArthur

In order to support multiple file parsing, we will need to be able to parse items from a file without specifically parsing an entire crate. This PR splits up the `parse_crate()` function in two and exposes the `parse_items()` function.

The function was previously hidden and didn't have the exact same behavior as the main loop of `parse_crate()`.

This will be especially useful when trying to expand 
```rust
mod <file>;
```
to
```rust
mod <file> {
    <items>
}
```
in the AST as we will need to parse the items present in the file.

Co-authored-by: CohenArthur <arthur.cohen@epita.fr>

2 files changed, 23 insertions, 39 deletions

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index 596a682..ccfff84 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -388,15 +388,12 @@ Parser<ManagedTokenSource>::done_end_of_file ()
   return lexer.peek_token ()->get_id () == END_OF_FILE;
 }
 
-// Parses a crate (compilation unit) - entry point
+// Parses a sequence of items within a module or the implicit top-level module
+// in a crate
 template <typename ManagedTokenSource>
-AST::Crate
-Parser<ManagedTokenSource>::parse_crate ()
+std::vector<std::unique_ptr<AST::Item>>
+Parser<ManagedTokenSource>::parse_items ()
 {
-  // parse inner attributes
-  AST::AttrVec inner_attrs = parse_inner_attributes ();
-
-  // parse items
   std::vector<std::unique_ptr<AST::Item>> items;
 
   const_TokenPtr t = lexer.peek_token ();
@@ -419,6 +416,20 @@ Parser<ManagedTokenSource>::parse_crate ()
       t = lexer.peek_token ();
     }
 
+  return items;
+}
+
+// Parses a crate (compilation unit) - entry point
+template <typename ManagedTokenSource>
+AST::Crate
+Parser<ManagedTokenSource>::parse_crate ()
+{
+  // parse inner attributes
+  AST::AttrVec inner_attrs = parse_inner_attributes ();
+
+  // parse items
+  std::vector<std::unique_ptr<AST::Item>> items = parse_items ();
+
   // emit all errors
   for (const auto &error : error_table)
     error.emit_error ();
@@ -992,37 +1003,6 @@ Parser<ManagedTokenSource>::parse_token_tree ()
     }
 }
 
-/* Parses a sequence of items within a module or the implicit top-level module
- * in a crate. Note: this is not currently used as parsing an item sequence
- * individually is pretty simple and allows for better error diagnostics and
- * detection. */
-template <typename ManagedTokenSource>
-std::vector<std::unique_ptr<AST::Item>>
-Parser<ManagedTokenSource>::parse_items ()
-{
-  std::vector<std::unique_ptr<AST::Item>> items;
-
-  // TODO: replace with do-while loop?
-  // infinite loop to save on comparisons (may be a tight loop) - breaks when
-  // next item is null
-  while (true)
-    {
-      std::unique_ptr<AST::Item> item = parse_item (false);
-
-      if (item != nullptr)
-	{
-	  items.push_back (std::move (item));
-	}
-      else
-	{
-	  break;
-	}
-    }
-
-  items.shrink_to_fit ();
-  return items;
-}
-
 // Parses a single item
 template <typename ManagedTokenSource>
 std::unique_ptr<AST::Item>
diff --git a/gcc/rust/parse/rust-parse.h b/gcc/rust/parse/rust-parse.h
index 1c7bd78..3920893 100644
--- a/gcc/rust/parse/rust-parse.h
+++ b/gcc/rust/parse/rust-parse.h
@@ -141,7 +141,6 @@ private:
   std::unique_ptr<AST::MacroMatchRepetition> parse_macro_match_repetition ();
 
   // Top-level item-related
-  std::vector<std::unique_ptr<AST::Item> > parse_items ();
   std::unique_ptr<AST::Item> parse_item (bool called_from_statement);
   std::unique_ptr<AST::VisItem> parse_vis_item (AST::AttrVec outer_attrs);
   std::unique_ptr<AST::MacroItem> parse_macro_item (AST::AttrVec outer_attrs);
@@ -580,11 +579,16 @@ private:
   bool done_end_of_file ();
 
   void add_error (Error error) { error_table.push_back (std::move (error)); }
+  std::vector<Error> &get_errors () { return error_table; }
 
 public:
   // Construct parser with specified "managed" token source.
   Parser (ManagedTokenSource tokenSource) : lexer (std::move (tokenSource)) {}
 
+  // Parse items without parsing an entire crate. This function is the main
+  // parsing loop of AST::Crate::parse_crate().
+  std::vector<std::unique_ptr<AST::Item> > parse_items ();
+
   // Main entry point for parser.
   AST::Crate parse_crate ();