The $parms identifier is a non tokenize version of the $1- identifier, effectively preserving spaces. It works everywhere where $1- can be used.
;Execute in mIRC's editbox with a single slash: /testingparms a b alias testingparms echo -a $len($1-) -- $len($parms)
Added: mIRC v7.52
Added on: 28 Feb 2018
Note: Unless otherwise stated, this was the date of original functionality.
Further enhancements may have been made in later versions.