[Gavino]

Originally Posted by lisztfr9

Very useful ! but

http://manao4.free.fr/mt_masktools.html

Don't say anything about mt_infix, or i'm blind

Ok it's shown as add (Alpha 5)

The on-line web page is hopelessly out of date, and covers only up to v2.0a27.
mt_infix was introduced in v2.0a37 (it was actually mt_polish that came in at alpha 5).

You need to look at the documentation in the masktools download zip file - documentation\mt_masktools.html.