I built a script shell to add signature to .mli 
as follow

When I use it for global variabale as hash table 
the signature is 

let L = hashtbl__new 30 ;;

L : hashtbl__t  _a 

instead of the real instantion of L 

======================= 
if test -f $1.ml
then
	echo $1.mli  "transformation  en cours"
else
	echo le fichier $1.ml n existe pas
	exit 
fi

sed '/$1/d' $1.ml|sed '/\#open/w .tmp' > /dev/null #recuperation des open sauf les open ayan comme nom le fichier passe

if test -f $1.mli
then
	camlc -c $1.mli			# on compile le fichier .mli
	echo "(* -------------------------------*)" >.tmp
	cat $1.mli >> .tmp		# insertion dans .tmp du fichier	
fi

echo "(* fonction de  $1.ml  -----------------*)" 	>>.tmp
camlc  -c -i $1.ml >> .tmp
mv .tmp  $1.mli


echo "verifier le fichier genere "