     [ port>> ] [ protocol>> protocol-port ] bi over =
     [ drop f ] when ;
 
+: ipv6-host ( host -- host/ipv6 ipv6? )
+    dup { [ "[" head? ] [ "]" tail? ] } 1&& [
+        1 swap [ length 1 - ] [ subseq ] bi t
+    ] [ f ] if ;
+
+: unparse-host ( url -- host )
+    host>> ipv6-host [ url-encode ] [ [ "[" "]" surround ] when ] bi* ;
+
 : unparse-host-part ( url -- )
     {
         [ unparse-username-password ]
-        [ host>> url-encode % ]
+        [ unparse-host % ]
         [ url-port [ ":" % # ] when* ]
         [ path>> "/" head? [ "/" % ] unless ]
     } cleave ;

! Copyright (C) 2008, 2011 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.

USING: accessors ascii assocs combinators fry io.pathnames
io.sockets io.sockets.secure kernel lexer linked-assocs make
math.parser multiline namespaces peg.ebnf present sequences
sequences.generalizations splitting strings strings.parser
urls.encoding vocabs.loader ;

: set-query-params ( url params -- url )
    [ swap set-query-param ] assoc-each ;

ERROR: malformed-port string ;

: parse-port ( string -- port/f )
    [ f ] [ dup string>number [ ] [ malformed-port ] ?if ] if-empty ;

: parse-host ( string -- host/f port/f )
    [
