I like it! I don't think it'll break anything; can you send a pull request? Then we'll be able to run such code reliably at the repl! That would be sweet.
Edit 38 minutes later: hmm, there's one issue. Right now you can type multiple expressions in on a single line, but this change would drop everything after the end of the first expression. A better approach would be to drop only whitespace and stop at the very first non-whitespace character.
