This change cleans up remove-aliases.py by extracting inline operator tokens like |-, comparison operators, and arithmetic operators into dedicated grammar rules. The parser behavior stays the same, but the grammar is now more structured and readable, which makes future changes to expression handling less error-prone. In practice, this is a small but useful maintainability improvement for anyone evolving the alias-removal logic.

Refactored the alias-removal grammar to define operator literals as named rules, making the parser easier to maintain and extend. - zhengqunkoo/hipsleek