revset: move tagging of alias arguments from tokenization to parsing phase In short, this patch moves the hack from tokenizedefn() to _relabelaliasargs(), which is called after parsing. This change aims to eliminate tight dependency on the revset tokenizer. Before this patch, we had to rewrite an alias argument to a pseudo function: "$1" -> "_aliasarg('$1')" ('symbol', '$1') -> ('function', ('symbol', '_aliasarg'), ('string', '$1')) This was because the tokenizer must generate tokens that are syntactically valid. By moving the process to the parsing phase, we can assign a unique tag to an alias argument. ('symbol', '$1') -> ('_aliasarg', '$1') Since new _aliasarg node never be generated from a user input, we no longer have to verify a user input at findaliases(). The test for _aliasarg("$1") is removed as it is syntactically valid and should pass the parsing phase.