substitute command :s with script

script.vim

" pokus - 1 search for items with at least 1 char between asterisks eg: not **
"	  2 substitute them with the same string with stripped spaces
"       list - mujList - is here for testing purposes
let flags = ''
let mujList = []
call cursor(1,1)
while search('\*\(.\{-}\)\*', flags,line("$")) > 0
	" last search register "/
	let @/='\*\(.\{-}\)\*'
	" trigger next search using gn object and copy it
	execute ':normal! ygn'
	" result of copying is in register"0
	let pomS = trim(@0,"* ")
	if strchars(pomS) > 0
		call add(mujList,[ @0,pomS] )
		execute ":normal! ct**".pomS."\e"
	endif
endwhile
echo mujList
echo "xxx"