discontinued special treatment of structure Ast: no pervasive content, no inclusion in structure Syntax;
if String.isPrefix "polyml" ml_system
then
(use "unicode_symbols.ML";
use "html_unicode.ML";
use "mime.ML";
use "http_status.ML";
use "http_util.ML";
use "xhtml.ML";
use "socket_util.ML";
use "scgi_req.ML";
use "scgi_server.ML";
use "echo.ML";
use "find_theorems.ML")
else ()