Initial data commit

Task/Empty-string/Icon/empty-string.icon

@@ -0,0 +1,16 @@
+s := ""                 # null string
+s := string('A'--'A')   # ... converted from cset difference
+s := char(0)[0:0]       # ... by slicing
+
+s1 == ""                # lexical comparison, could convert s1 to string
+s1 === ""               # comparison won't force conversion
+*s1 = 0                 # zero length, however, *x is polymorphic
+*string(s1) = 0         # zero length string
+
+s1 ~== ""               # non null strings comparisons
+s1 ~=== ""
+*string(s1) ~= 0
+
+s := &null              # NOT a null string, null type
+/s                      # test for null type
+\s                      # test for non-null type