On second though, it doesn't clash. It's actually a straightforward extension to implement:
-{ mlp.expr.add_postfix_sequence{ "`",
mlp.id, "`",
mlp.expr,
prec = 30, assoc = "left", builder = |x| `Call{ x[2], x[1], x[3] } } }
But there's still an issue, it relies on a partially unimplemented feature of the grammar generator: precedence and associativity hints aren't handled properly by postfix sequences, so the extension above will behave as if it had infinite precedence and were right associative. But that will be fixed eventually, so this infix call extension will work.
