Problems with ~ and ~~

[DaVinci <bombadil@wanadoo.es>]

 Hi all.

 I have problems to understand pattern extraction.

 When trying:

 	; a = {~~ (foo.c foo.x bar.h) *.[ch]}
	; echo $a

 I get:

 	{~~ (foo.c foo.x bar.h) *.[ch]}

 Is this normal?.

 						David