(lists-to-xmllist?)->string?
convert lists to xml, the list should obey below rules.
1. First node of list should be a string? or symbol? It represent node name.
'("H1")-><H1/>
2. All the pairs represent node’s attributes.
'("H1"("attr1"."1")("attr2"."2"))-><H1"attr1"="1""attr2"="2"/>
3. If have children, string/symbol represent its value, or, the lists represents its children. Node’s children should either string? or symbol? or lists?, only one of these three types.
'("H1""haha")-><H1>haha</H1>'("H1"("H2""haha"))-><H1><H2>haha</H2></H1>
(lists-to-compact_xmllist?)->string?
remove all the format characters.
'("H1"("H2""haha"))-><H1><H2>haha</H2></H1>