Module c2rust_transpile::rust_ast::comment_store

This module handles accumulating / re-arranging comments for the Rust AST.

The only way we have found to have comments inserted into the pretty-printed Rust output is via a comment vector. The Rust pretty-printer accepts a vector of comments and, before printing any AST node, it dumps out the prefix of comments whose position is less than the span of the AST node.

The logic for creating/storing a comment vector is in CommentStore. For example, if you want to add a comment to a match arm:

  let sp: Span = cmmt_store.add_comment_lines(vec!["Some comment on an arm"]);
  let arm = mk().span(sp).arm(pats, None, body);
  ...

Right before printing the output, it is a good idea to use the CommentTraverser to make sure that the comment vector is in the right order. That just means doing something like this:

  let trav: CommentTraverser = cmmt_store.into_comment_traverser();
  let updated_module: Mod = trav.traverse_mod(module);
  let updated_cmmt_store = trav.into_comment_store();

Structs

CommentStore
CommentTraverser