if /true/	fodder
/1/	1
if /false/
/2/	2
endif		fodder
/3/	3
endif
/a/!/b/	a!b
/c/
/(1)(2)(3)(5)/	($1)($2)($3)($4)($5)
/(1)(2)(3)(4)/	($1)($2)($3)($4)
/(1)(2)(3)/	($1)($2)($3)
# trailing whitespace below
if /bar/ 	
if !/xyzzy/
/(elbereth)/	($1)
!/(bogus)/	($1)
!/find/		Don't have a liquor license
endif
endif	 
# trailing whitespace above
!
# dangling endif and if
endif
endif
if /./
if /./
