IN: scratchpad \ path-without-extension see
USING: kernel sequences ;
IN: scratchpad
: path-without-extension ( path -- path )
    [ [ 46 = ] find-last drop ] keep swap head ;
IN: scratchpad \ bump-ext see
USING: io.pathnames kernel math math.parser sequences ;
IN: scratchpad
: bump-ext ( path -- path )
    dup file-extension string>number [
        [ path-without-extension "." ] dip 1 +
        number>string 3append
    ] [ ".1" append ] if* ;
IN: scratchpad "/Users/username/Desktop/dummy.txt" bump-ext

--- Data stack:
"/Users/username/Desktop/dummy.txt.1"
IN: scratchpad bump-ext

--- Data stack:
"/Users/username/Desktop/dummy.txt.2"
IN: scratchpad bump-ext .
"/Users/username/Desktop/dummy.txt.3"
IN: scratchpad "/Users/username/Desktop/dummy" bump-ext

--- Data stack:
"/Users/username/Desktop/dummy.1"
IN: scratchpad bump-ext .
"/Users/username/Desktop/dummy.2"