%% =====================================================================
%% This library is free software; you can redistribute it and/or modify
%% it under the terms of the GNU Lesser General Public License as
%% published by the Free Software Foundation; either version 2 of the
%% License, or (at your option) any later version.
%%
%% This library is distributed in the hope that it will be useful, but
%% WITHOUT ANY WARRANTY; without even the implied warranty of
%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%% Lesser General Public License for more details.
%%
%% You should have received a copy of the GNU Lesser General Public
%% License along with this library; if not, write to the Free Software
%% Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
%% USA
%%
%% @author Richard Carlsson <carlsson.richard@gmail.com>
%% @author Kenneth Lundin <kenneth@erix.ericsson.se>
%% @copyright 2001-2004 Richard Carlsson
%% @see edoc_layout
%% @end
%% =====================================================================

%% @doc The OTP SGML layout module for EDoc. See the module {@link edoc}
%% for details on usage.

%% Note that this is written so that it is *not* depending on edoc.hrl!

-module(otpsgml_layout).

-export([module/2, overview/2,type/1]).

-import(edoc_report, [report/2]).

-include_lib("xmerl/include/xmerl.hrl").

-define(SGML_EXPORT, xmerl_otpsgml).
-define(DEFAULT_XML_EXPORT, ?SGML_EXPORT).
-define(STYLESHEET, "stylesheet.css").
-define(NL, "\n").
-define(DESCRIPTION_TITLE, "Description").
-define(DESCRIPTION_LABEL, "description").
-define(DATA_TYPES_TITLE, "Data Types").
-define(DATA_TYPES_LABEL, "types").
-define(FUNCTION_INDEX_TITLE, "Function Index").
-define(FUNCTION_INDEX_LABEL, "index").
-define(FUNCTIONS_TITLE, "Function Details").
-define(FUNCTIONS_LABEL, "functions").


%% @doc The layout function.
%%
%% Options:
%% <dl>
%%  <dt>{@type {index_columns, integer()@}}
%%  </dt>
%%  <dd>Specifies the number of column pairs used for the function
%%      index tables. The default value is 1.
%%  </dd>
%%  <dt>{@type {stylesheet, string()@}}
%%  </dt>
%%  <dd>Specifies the URI used for referencing the stylesheet. The
%%      default value is `"stylesheet.css"'. If an empty string is
%%      specified, no stylesheet reference will be generated.
%%  </dd>
%%  <dt>{@type {xml_export, Module::atom()@}}
%%  </dt>
%%  <dd>Specifies an {@link //xmerl. `xmerl'} callback module to be
%%      used for exporting the documentation. See {@link
%%      //xmerl/xmerl:export_simple/3} for details.
%%  </dd>
%% </dl>
%%
%% @see edoc:layout/2

-record(opts, {root, stylesheet, index_columns}).

module(Element, Options) ->
    XML = layout_module(Element, init_opts(Element, Options)),
    Export = proplists:get_value(xml_export, Options,
				 ?DEFAULT_XML_EXPORT),
    xmerl:export_simple([XML], Export, []).

% Put layout options in a data structure for easier access.

init_opts(Element, Options) ->
    R = #opts{root = get_attrval(root, Element),
	      index_columns = proplists:get_value(index_columns,
						  Options, 1)
	     },
    case proplists:get_value(stylesheet, Options) of
	undefined ->
	    S = edoc_lib:join_uri(R#opts.root, ?STYLESHEET),
	    R#opts{stylesheet = S};
	"" ->
	    R;  % don't use any stylesheet
	S when is_list(S) ->
	    R#opts{stylesheet = S}; 
	_ ->
	    report("bad value for option `stylesheet'.", []),
	    exit(error)
    end.


%% =====================================================================
%% XML-BASED LAYOUT ENGINE
%% =====================================================================

%% We assume that we have expanded XML data.

%% <!ELEMENT module (moduleName, moduleFullName, behaviour*, description?,
%%                   author*, version?, since?, copyright?, deprecated?,
%%                   see*, reference*, typedecls?, functions)>
%% <!ATTLIST module
%%   root CDATA #IMPLIED>
%% <!ELEMENT moduleName (#PCDATA)>
%% <!ELEMENT moduleFullName (#PCDATA)>
%% <!ELEMENT behaviour (#PCDATA)>
%% <!ATTLIST behaviour
%%   href CDATA #IMPLIED>
%% <!ELEMENT description (briefDescription, fullDescription?)>
%% <!ELEMENT briefDescription (#PCDATA)>
%% <!ELEMENT fullDescription (#PCDATA)>
%% <!ELEMENT author EMPTY>
%% <!ATTLIST author
%%   name CDATA #REQUIRED
%%   email CDATA #IMPLIED
%%   website CDATA #IMPLIED>
%% <!ELEMENT version (#PCDATA)>
%% <!ELEMENT since (#PCDATA)>
%% <!ELEMENT copyright (#PCDATA)>
%% <!ELEMENT deprecated (description)>
%% <!ELEMENT see (#PCDATA)>
%% <!ATTLIST see
%%   name CDATA #REQUIRED
%%   href CDATA #IMPLIED>
%% <!ELEMENT reference (#PCDATA)>
%% <!ELEMENT typedecls (typedecl+)>
%% <!ELEMENT functions (function+)>

layout_module(#xmlElement{name = module, content = Es}=E, _Opts) ->
    Name = get_attrval(name, E),
    Desc = get_content(description, Es),
    ShortDesc = get_content(briefDescription, Desc),
    FullDesc = get_content(fullDescription, Desc),
    Functions = [E || E <- get_content(functions, Es)],
    SortedFs = lists:sort([{function_name(E), E} || E <- Functions]),
    Types = get_content(typedecls, Es),
    SortedTs = lists:sort([{type_name(E), E} || E <- Types]),
    Header = {header, [
		       ?NL,{title, [Name]},
		       ?NL,{prepared, [""]},
		       ?NL,{responsible, [""]},
		       ?NL,{docno, ["1"]},
		       ?NL,{approved, [""]},
		       ?NL,{checked, [""]},
		       ?NL,{date, [""]},
		       ?NL,{rev, ["A"]},
		       ?NL,{file, [Name++".sgml"]}
		      ]},
    Module = {module, [Name]},
    ModuleSummary = {modulesummary, ShortDesc},
    {Short,Long} = find_first_p(FullDesc,[]),
    Description = {description, [?NL,{p,Short}|Long]++[?NL|types(SortedTs)]},
    Funcs = functions(SortedFs),
    Authors = {authors, authors(Es)},
    See = sees1(Es),
    {erlref, [
	      ?NL,Header,
	      ?NL,Module,
	      ?NL,ModuleSummary,
	      ?NL,Description,
	      ?NL,Funcs,
	      ?NL,See,
	      ?NL,Authors
	     ]
    }.

stylesheet(Opts) ->
    case Opts#opts.stylesheet of
	undefined ->
	    [];
	CSS ->
	    [{link, [{rel, "stylesheet"},
		     {type, "text/css"},
		     {href, CSS}], []},
	     ?NL]
    end.

% doc_index(FullDesc, Functions, Types) ->
%     case doc_index_rows(FullDesc, Functions, Types) of
% 	[] -> [];
% 	Rs ->
% 	    [{ul, [{li, [{a, [{href, local_label(R)}], [T]}]}
% 		   || {T, R} <- Rs]}]
%     end.

% doc_index_rows(FullDesc, Functions, Types) ->
%     (if FullDesc == [] -> [];
% 	true -> [{?DESCRIPTION_TITLE, ?DESCRIPTION_LABEL}]
%      end
%      ++ if Types == [] -> [];
% 	   true -> [{?DATA_TYPES_TITLE, ?DATA_TYPES_LABEL}]
% 	end
%      ++ if Functions == [] -> [];
% 	   true -> [{?FUNCTION_INDEX_TITLE, ?FUNCTION_INDEX_LABEL},
% 		    {?FUNCTIONS_TITLE, ?FUNCTIONS_LABEL}]
% 	end).

% function_index(Fs, Cols) ->
%     case function_index_rows(Fs, Cols, []) of
% 	[] -> [];
% 	Rows ->
% 	    [?NL,
% 	     {h2, [{a, [{name, ?FUNCTION_INDEX_LABEL}],
% 		    [?FUNCTION_INDEX_TITLE]}]},
% 	     ?NL,
% 	     {table, [{width, "100%"}, {border, 1}], Rows},
% 	     ?NL]
%     end.

% function_index_rows(Fs, Cols, Title) ->
%     Rows = (length(Fs) + (Cols - 1)) div Cols,
%     (if Title == [] -> [];
% 	true -> [{tr, [{th, [{colspan, Cols * 2}, {align, left}],
% 			[Title]}]},
% 		 ?NL]
%      end
%      ++ lists:flatmap(fun index_row/1,
% 		      edoc_lib:transpose(edoc_lib:segment(Fs, Rows)))).

% index_row(Fs) ->
%     [{tr, lists:flatmap(fun index_col/1, Fs)}, ?NL].

% index_col({Name, F=#xmlElement{content = Es}}) ->
%     [{td, [{valign, "top"}], label_href([Name], F)},
%      {td, index_desc(Es)}].

index_desc(Es) ->
    Desc = get_content(description, Es),
    case get_content(briefDescription, Desc) of
	[] ->
	    equiv(Es);    % no description at all if no equiv
	ShortDesc ->
	    ShortDesc
    end.

% label_href(Content, F) ->
%     case get_attrval(label, F) of
% 	"" -> Content;
% 	Ref -> [{a, [{href, local_label(Ref)}], Content}]
%     end.


%% <!ELEMENT function (args, typespec?, equiv?, description?, since?,
%%                     deprecated?, see*)>
%% <!ATTLIST function
%%   name CDATA #REQUIRED
%%   arity CDATA #REQUIRED
%%   exported NMTOKEN(yes | no) #REQUIRED
%%   label CDATA #IMPLIED>
%% <!ELEMENT args (arg*)>
%% <!ELEMENT arg description?>
%% <!ATTLIST arg name CDATA #REQUIRED>


%% <!ELEMENT equiv (expr, see?)>
%% <!ELEMENT expr (#PCDATA)>

% functions(Fs) ->
%     Es = lists:flatmap(fun ({Name, E}) -> function(Name, E) end, Fs),
%     if Es == [] -> [];
%        true ->
% 	    [?NL,
% 	     {h2, [{a, [{name, ?FUNCTIONS_LABEL}], [?FUNCTIONS_TITLE]}]},
% 	     ?NL | Es]
%     end.

functions(Fs) ->
    Es = lists:flatmap(fun ({Name, E}) -> function(Name, E) end, Fs),
    if Es == [] -> [];
       true ->
	    {funcs, Es}
    end.

% is_exported(E) ->
%     case get_attrval(exported, E) of
% 	"yes" -> true;
% 	_ -> false
%     end.

% function(Name, E=#xmlElement{content = Es}) ->
%     ([?NL, {h3, label_anchor([Name], E)}, ?NL]
%      ++ case typespec(get_content(typespec, Es)) of
% 	    [] ->
% 		signature(get_content(arguments, Es),
% 			  get_text(functionName, Es));
% 	    Spec -> Spec
% 	end
%      ++ equiv(Es)
%      ++ deprecated(Es, "function")
%      ++ fulldesc(Es)
%      ++ since(Es)
%      ++ sees(Es)).

function(_Name, E=#xmlElement{content = Es}) ->
    TypeSpec = get_content(typespec, Es),
    [?NL,{func, [ ?NL,
		  {name, 
%			  case typespec(get_content(typespec, Es)) of
			  case funcheader(TypeSpec) of
			      [] ->
				  signature(get_content(args, Es),
					    get_attrval(name, E));
			      Spec -> Spec
			  end
			 },
		  ?NL,{fsummary, fsummary(Es)},
%		  ?NL,{type, local_types(TypeSpec)},
		  ?NL,local_types(TypeSpec),
		  ?NL,{desc, label_anchor(E)++fulldesc(Es)++sees(Es)}
	   ]}].

fsummary([]) -> ["\s"];
fsummary(Es) ->
    Desc = get_content(description, Es),
    case get_content(briefDescription, Desc) of
	[] ->
	    fsummary_equiv(Es);    % no description at all if no equiv
	ShortDesc ->
	    ShortDesc
    end.


fsummary_equiv(Es) ->
    case get_content(equiv, Es) of
	[] -> ["\s"];
	Es1 ->
	    case get_content(expr, Es1) of
		[] -> ["\s"];
		[Expr] ->
		    ["Equivalent to ", Expr, ".",?NL]
	    end
    end.


function_name(E) ->
    get_attrval(name, E) ++ "/" ++ get_attrval(arity, E).

label_anchor(E) ->
    case get_attrval(label, E) of
	"" -> [];
	Ref -> [{marker, [{id, Ref}],[]},?NL]
    end.

label_anchor(Content, E) ->
    case get_attrval(label, E) of
	"" -> Content;
	Ref -> {p,[{marker, [{id, Ref}],[]},
		   {em, Content}]}
    end.

%% <!ELEMENT args (arg*)>
%% <!ELEMENT arg (argName, description?)>
%% <!ELEMENT argName (#PCDATA)>

%% This is currently only done for functions without type spec.

signature(Es, Name) -> 
%    [{tt, [Name, "("] ++ seq(fun arg/1, Es) ++ [") -> term()", ?NL]}].
    [Name, "("] ++ seq(fun arg/1, Es) ++ [") -> term()", ?NL].

arg(#xmlElement{content = Es}) ->
    [get_text(argName, Es)].

%% <!ELEMENT typespec (erlangName, type, localdef*)>

% typespec([]) -> [];
% typespec(Es) ->
%     [{p, ([{tt, ([t_name(get_elem(qualifiedName, Es))]
% 		 ++ t_type(get_content(type, Es)))}]
% 	  ++ local_defs(get_elem(definition, Es)))},
%      ?NL].

funcheader([]) -> [];
funcheader(Es) ->
    [t_name(get_elem(erlangName, Es))] ++ t_utype(get_elem(type, Es)).

local_types([]) -> [];
local_types(Es) ->
    local_defs2(get_elem(localdef, Es)).

local_defs2([]) -> [];
local_defs2(Es) ->
    {type,[?NL | [{v, localdef(E)} || E <- Es]]}.

%% <!ELEMENT typedecl (typedef, description?)>
%% <!ELEMENT typedef (erlangName, argtypes, type?, localdef*)>

types([]) -> [];
types(Ts) ->
    Es = lists:flatmap(fun ({Name, E}) -> typedecl(Name, E) end, Ts),
    [?NL,
%    {h2, [{a, [{name, ?DATA_TYPES_LABEL}],
%	   [?DATA_TYPES_TITLE]}]},
%    ?NL | Es]
     {p,[{marker, [{id, ?DATA_TYPES_LABEL}],[]},
	 {em,[?DATA_TYPES_TITLE]}]},
     ?NL, {taglist,[?NL|Es]}].

%%type(Name, E=#xmlElement{content = Es}) ->
%%    ([?NL, {h3, label_anchor([Name, "()"], E)}, ?NL]
%%     ++ [{p, typedef(get_content(typedef, Es))}, ?NL]
%%     ++ fulldesc(Es)).
typedecl(_Name, #xmlElement{content = Es}) ->
    [{tag, typedef(get_content(typedef, Es))},?NL,{item,fulldesc(Es)},?NL].


type_name(#xmlElement{content = Es}) ->
    t_name(get_elem(erlangName, get_content(typedef, Es))).

typedef(Es) ->
    Name = ([t_name(get_elem(erlangName, Es)), "("]
  	    ++ seq(fun t_utype_elem/1, get_content(argtypes, Es), [")"])),
    (case get_elem(type, Es) of
 	 [] -> [{b, ["abstract datatype"]}, ": ", {tt, Name}];
 	 Type ->
	     [{tt, Name ++ [" = "] ++ t_utype(Type)}]
     end
     ++ local_defs(get_elem(localdef, Es))).

local_defs([]) -> [];
local_defs(Es) ->
    [?NL, {ul, [{li, [{tt, localdef(E)}]} || E <- Es]}].

localdef(E = #xmlElement{content = Es}) ->
    (case get_elem(typevar, Es) of
	 [] -> 
	     label_anchor(t_abstype(get_content(abstype, Es)), E);
	 [V] ->
	     t_var(V)
     end
     ++ [" = "] ++ t_utype(get_elem(type, Es))).

fulldesc(Es) ->
    case get_content(fullDescription, get_content(description, Es)) of
%	[] -> [?NL];
	[] -> index_desc(Es);
%	Desc -> [{p, Desc}, ?NL]
	Desc ->
	    {Short,Long} = find_first_p(Desc,[]),
	    [?NL,{p,Short}|Long] ++[?NL]
    end.

find_first_p([#xmlElement{name=p}|_]=Long,Short) ->
    {lists:reverse(Short),Long};
find_first_p([H|T],Short) ->
    find_first_p(T,[H|Short]);
find_first_p([],Short) ->
    {lists:reverse(Short),[]}.


sees1(Es) ->
    case get_elem(see, Es) of
	[] -> [];
	Es1 ->
	    {section,[{title,["See also"]},{p,seq(fun see/1, Es1, [])}]}
    end.

sees(Es) ->
    case get_elem(see, Es) of
	[] -> [];
	Es1 ->
	    [{p, [{em, ["See also:"]}, " "] ++ seq(fun see/1, Es1, ["."])},
	     ?NL]
    end.

see(E=#xmlElement{content = Es}) ->
    see(E,Es).

see(E, Es) ->
    case get_attrval(href, E) of
	"" -> Es;
	Ref -> 
	    case lists:reverse(Ref) of
		"lmgs.ppa_"++Ppa -> 
		    App = lists:reverse(Ppa),
		    [{seealso, [{marker, App++"_app"}], [App]},"(6)"];
		"lmgs."++Dom -> 
		    Mod = lists:reverse(Dom),
		    [{seealso, [{marker, Mod}], [Mod]},"(3)"];
		_ -> 
		    [{seealso, [{marker, Ref}], Es}]
	    end
    end.

equiv(Es) ->
    case get_content(equiv, Es) of
	[] -> ["\s"];
	Es1 ->
	    case get_content(expr, Es1) of
		[] -> [];
		[Expr] ->
%		    Expr1 = {tt, [Expr]},
%		    Expr1 = {c, [Expr]},
		    Expr1 = [Expr],
		    Expr2 = case get_elem(see, Es1) of
				[] ->
				    {c,Expr1};
				[E=#xmlElement{}] ->
%				    see(E,Expr1)
 				    case get_attrval(href, E) of
 					"" ->
 					    {c,Expr1};
 					Ref ->
 					    {seealso, [{marker, Ref}], Expr1}
 				    end
			    end,
		    [{p, ["Equivalent to ", Expr2, "."]}, ?NL]
	    end
    end.

% replace_minus_with_percent([$-|T]) ->
%     [$%|T];
% replace_minus_with_percent([H|T]) ->
%     [H|replace_minus_with_percent(T)].

copyright(Es) ->
    case get_content(copyright, Es) of
	[] -> [];
	Es1 ->
	    [{p, ["Copyright \251 " | Es1]}, ?NL]
    end.

version(Es) ->
    case get_content(version, Es) of
	[] -> [];
	Es1 ->
	    [{p, [{b, ["Version:"]}, " " | Es1]}, ?NL]
    end.

since(Es) ->
    case get_content(since, Es) of
	[] -> [];
	Es1 ->
	    [{p, [{b, ["Introduced in:"]}, " " | Es1]}, ?NL]
    end.

deprecated(Es, S) ->
    Es1 = get_content(description, get_content(deprecated, Es)),
    case get_content(fullDescription, Es1) of
	[] -> [];
	Es2 ->
	    [{p, [{b, ["This " ++ S ++ " is deprecated:"]}, " " | Es2]},
	     ?NL]
    end.

% behaviours(Es) ->
%     case get_elem(behaviour, Es) of
% 	[] -> [];
% 	Es1 ->
% 	    [{p, [{b, ["Behaviour:"]}, " "] ++ seq(fun behaviour/1, Es1, ["."])},
% 	     ?NL]
%     end.

% behaviour(E=#xmlElement{content = Es}) ->
%     case get_attrval(href, E) of
% 	"" -> [{tt, Es}];
% 	Ref -> [{a, [{href, Ref}], [{tt, Es}]}]
%     end.

authors(Es) ->
    case get_elem(author, Es) of
	[] -> [?NL,{aname,["\s"]},?NL,{email,["\s"]}];
	Es1 -> [?NL|seq(fun author/1, Es1, [])]
%
%	    [{p, [{b, ["Authors:"]}, " "] ++ seq(fun author/1, Es1, ["."])},
%	     ?NL]
    end.


%% <!ATTLIST author
%%   name CDATA #REQUIRED
%%   email CDATA #IMPLIED
%%   website CDATA #IMPLIED>

author(E=#xmlElement{}) ->
    Name = case get_attrval(name, E) of
	       [] -> "\s";
	       N -> N
	   end,
    Mail = case get_attrval(email, E) of
	       [] -> "\s";
	       M -> M
	   end,
    [?NL,{aname,[Name]},?NL,{email,[Mail]}].

% author(E=#xmlElement{}) ->
%     Name = get_attrval(name, E),
%     Mail = get_attrval(email, E),
%     URI = get_attrval(website, E),
%     (if Name == Mail ->
% 	     [{a, [{href, "mailto:" ++ Mail}],[{tt, [Mail]}]}];
% 	true ->
% 	     if Mail == "" -> [Name];
% 		true -> [Name, " (", {a, [{href, "mailto:" ++ Mail}],
% 				      [{tt, [Mail]}]}, ")"]
% 	     end
%      end
%      ++ if URI == "" -> [];
% 	   true -> [" [", {em, ["web site:"]}, " ",
% 		    {tt, [{a, [{href, URI}], [URI]}]}, "]"]
% 	end).

references(Es) ->
    case get_elem(reference, Es) of
	[] -> [];
	Es1 ->
	    [{p, [{b, ["References"]},
		  {ul, [{li, C} || #xmlElement{content = C} <- Es1]}]},
	     ?NL]
    end.

t_name([E]) ->
    N = get_attrval(name, E),
    case get_attrval(module, E) of
	"" -> N;
	M ->
	    S = M ++ ":" ++ N,
	    case get_attrval(app, E) of
		"" -> S;
		A -> "//" ++ A ++ "/" ++ S
	    end
    end.

t_utype([E]) ->
    t_utype_elem(E).

t_utype_elem(E=#xmlElement{content = Es}) ->
    case get_attrval(name, E) of
	"" -> t_type(Es);
	Name ->
	    T = t_type(Es),
	    case T of
		[Name] -> T;    % avoid generating "Foo::Foo"
		T -> [Name] ++ ["::"] ++ T
	    end
    end.

t_type([E=#xmlElement{name = typevar}]) ->
    t_var(E);
t_type([E=#xmlElement{name = atom}]) ->
    t_atom(E);
t_type([E=#xmlElement{name = integer}]) ->
    t_integer(E);
t_type([E=#xmlElement{name = float}]) ->
    t_float(E);
t_type([#xmlElement{name = nil}]) ->
    t_nil();
t_type([#xmlElement{name = list, content = Es}]) ->
    t_list(Es);
t_type([#xmlElement{name = tuple, content = Es}]) ->
    t_tuple(Es);
t_type([#xmlElement{name = 'fun', content = Es}]) ->
    t_fun(Es);
t_type([E = #xmlElement{name = abstype, content = Es}]) ->
    T = t_abstype(Es),
%    see(E,T);
     case get_attrval(href, E) of
 	"" -> T;
 %	Ref -> [{seealso, [{marker, Ref}], T}]
 	_Ref -> T
     end;
t_type([#xmlElement{name = union, content = Es}]) ->
    t_union(Es).

t_var(E) ->
    [get_attrval(name, E)].


t_atom(E) ->
    [get_attrval(value, E)].

t_integer(E) ->
    [get_attrval(value, E)].

t_float(E) ->
    [get_attrval(value, E)].

t_nil() ->
    ["[]"].

t_list(Es) ->
    ["["] ++ t_utype(get_elem(type, Es)) ++ ["]"].

t_tuple(Es) ->
    ["{"] ++ seq(fun t_utype_elem/1, Es, ["}"]).

t_fun(Es) ->
    ["("] ++ seq(fun t_utype_elem/1, get_content(argtypes, Es),
		 [") -> "] ++ t_utype(get_elem(type, Es))).

t_abstype(Es) ->
%    ([t_name(get_elem(qualifiedName, Es)), "("]
%     ++ seq(fun t_type_elem/1, get_elem(type, Es), [")"])).
    case split_at_colon(t_name(get_elem(erlangName, Es)),[]) of
	{Mod,Type} -> 
	    [Type, "("] ++ 
		seq(fun t_utype_elem/1, get_elem(type, Es), [")"]) ++ 
		[" (see module ", Mod, ")"];
	Type ->
	    [Type, "("] ++ 
		seq(fun t_utype_elem/1, get_elem(type, Es), [")"])
    end.

%% Split at one colon, but not at two (or more)
split_at_colon([$:,$:|_]=Rest,Acc) ->
    lists:reverse(Acc)++Rest;
split_at_colon([$:|Type],Acc) ->
    {lists:reverse(Acc),Type};
split_at_colon([Char|Rest],Acc) ->
    split_at_colon(Rest,[Char|Acc]);
split_at_colon([],Acc) ->
    lists:reverse(Acc).

% t_par(Es) ->
%     T = t_type(get_content(type, Es)),
%     case get_elem(variable, Es) of
% 	[] -> T;
% 	[V0] -> case t_variable(V0) of
% 		   T -> T;
% 		   V -> V ++ ["::"] ++ T
% 	       end
%     end.

% t_par_elem(#xmlElement{content = Es}) -> t_par(Es).

t_union(Es) ->
    seq(fun t_utype_elem/1, Es, " | ", []).

seq(F, Es) ->
    seq(F, Es, []).

seq(F, Es, Tail) ->
    seq(F, Es, ", ", Tail).

seq(F, [E], _Sep, Tail) ->
    F(E) ++ Tail;
seq(F, [E | Es], Sep, Tail) ->
    F(E) ++ [Sep] ++ seq(F, Es, Sep, Tail);
seq(_F, [], _Sep, Tail) ->
    Tail.

get_elem(Name, [#xmlElement{name = Name} = E | Es]) ->
    [E | get_elem(Name, Es)];
get_elem(Name, [_ | Es]) ->
    get_elem(Name, Es);
get_elem(_, []) ->
    [].

get_attr(Name, [#xmlAttribute{name = Name} = A | As]) ->
    [A | get_attr(Name, As)];
get_attr(Name, [_ | As]) ->
    get_attr(Name, As);
get_attr(_, []) ->
    [].

get_attrval(Name, #xmlElement{attributes = As}) ->
    case get_attr(Name, As) of
	[#xmlAttribute{value = V}] ->
	    V;
	[] -> ""
    end.

get_content(Name, Es) ->
    case get_elem(Name, Es) of
	[#xmlElement{content = Es1}] ->
	    Es1;
	[] -> []
    end.

get_text(Name, Es) ->
    case get_content(Name, Es) of
	[#xmlText{value = Text}] ->
	    Text;
	[] -> ""
    end.

% local_label(R) ->
%     "#" ++ R.

xml(Title, CSS, Body) ->
    {html, [?NL,
	    {head, [?NL,
		    {title, [Title]},
		    ?NL] ++ CSS},
	    ?NL,
	    {body, [{bgcolor, "white"}], Body},
	    ?NL]
    }.

%% ---------------------------------------------------------------------

 type(E) ->
     type(E, []).

% type(E, Ds) ->
%     xmerl:export_simple_content(t_utype_elem(E) ++ local_defs(Ds),
% 				?HTML_EXPORT).
 type(E, Ds) ->
     xmerl:export_simple_content(t_utype_elem(E) ++ local_defs(Ds),
 				?SGML_EXPORT).

overview(E=#xmlElement{name = overview, content = Es}, Options) ->
    Opts = init_opts(E, Options),
    Title = get_text(title, Es),
    Desc = get_content(description, Es),
%    ShortDesc = get_content(briefDescription, Desc),
    FullDesc = get_content(fullDescription, Desc),
    Body = ([?NL, {h1, [Title]}, ?NL]
%	    ++ ShortDesc
	    ++ copyright(Es)
	    ++ version(Es)
	    ++ since(Es)
	    ++ deprecated(Es, "application")
	    ++ authors(Es)
	    ++ references(Es)
	    ++ sees(Es)
	    ++ FullDesc),
    XML = xml(Title, stylesheet(Opts), Body),
    xmerl:export_simple([XML], ?SGML_EXPORT, []).