SmartEiffel doesn't have is_space.

json/scanner/json_parser.e

@@ -381,7 +381,7 @@ feature {NONE} -- Implementation
 			end
 			from
 			until
-				not actual.is_space or  not actual.is_equal ('%R') or
+				not actual.is_equal (' ') or not actual.is_equal ('%R') or
 				not actual.is_equal ('%U') or  not actual.is_equal ('%T')
 				or not actual.is_equal ('%N') or not has_next
 			loop

json/scanner/json_reader.e

@@ -74,7 +74,7 @@ feature -- Commands
 			-- Remove withe spaces
 		do
 			from
-			until not actual.is_space or not has_next
+			until actual /= ' ' or not has_next
 			loop
 				next
 			end