1%% =====================================================================
2%% Licensed under the Apache License, Version 2.0 (the "License"); you may
3%% not use this file except in compliance with the License. You may obtain
4%% a copy of the License at <http://www.apache.org/licenses/LICENSE-2.0>
5%%
6%% Unless required by applicable law or agreed to in writing, software
7%% distributed under the License is distributed on an "AS IS" BASIS,
8%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
9%% See the License for the specific language governing permissions and
10%% limitations under the License.
11%%
12%% Alternatively, you may use this file under the terms of the GNU Lesser
13%% General Public License (the "LGPL") as published by the Free Software
14%% Foundation; either version 2.1, or (at your option) any later version.
15%% If you wish to allow use of your version of this file only under the
16%% terms of the LGPL, you should delete the provisions above and replace
17%% them with the notice and other provisions required by the LGPL; see
18%% <http://www.gnu.org/licenses/>. If you do not delete the provisions
19%% above, a recipient may use your version of this file under the terms of
20%% either the Apache License or the LGPL.
21%%
22%% @private
23%% @copyright 2001-2005 Richard Carlsson
24%% @author Richard Carlsson <carlsson.richard@gmail.com>
25%% @see edoc
26%% @end
27%% =====================================================================
28
29%% @doc EDoc macro expansion
30
31-module(edoc_macros).
32
33-export([expand_tags/3, std_macros/1, check_defs/1]).
34
35-import(edoc_report, [report/2, error/3, warning/4]).
36
37-include("edoc.hrl").
38-include("edoc_types.hrl").
39
40-define(DEFAULT_XML_EXPORT, xmerl_html).
41
42
43std_macros(Env) ->
44    (if Env#env.module =:= [] -> [];
45	true -> [{module, atom_to_list(Env#env.module)}]
46     end
47     ++
48     [{date, fun date_macro/3},
49      {docRoot, Env#env.root},
50      {link, fun link_macro/3},
51      {section, fun section_macro/3},
52      {time, fun time_macro/3},
53      {type, fun type_macro/3},
54      {version, fun version_macro/3}]).
55
56
57%% Check well-formedness of user-specified list of macro definitions.
58
59check_defs([{K, D} | Ds]) when is_atom(K), is_list(D) ->
60    check_defs(Ds);
61check_defs([X | _Ds]) ->
62    report("bad macro definition: ~P.", [X, 10]),
63    exit(error);
64check_defs([]) ->
65    ok.
66
67%% Code for special macros should throw {error, Line, Reason} for error
68%% reporting, where Reason and Line are passed to edoc_report:error(...)
69%% together with the file name etc. The expanded text must be flat!
70
71date_macro(_S, _Line, _Env) ->
72    edoc_lib:datestr(date()).
73
74time_macro(_S, _Line, _Env) ->
75    edoc_lib:timestr(time()).
76
77version_macro(S, Line, Env) ->
78    date_macro(S, Line, Env)
79	++ " " ++ time_macro(S, Line, Env).
80
81link_macro(S, Line, Env) ->
82    {S1, S2} = edoc_lib:split_at_stop(S),
83    Ref = edoc_parser:parse_ref(S1, Line),
84    URI = edoc_refs:get_uri(Ref, Env),
85    Txt = if S2 =:= [] -> "<code>" ++ S1 ++ "</code>";
86	     true -> S2
87	  end,
88    Target = case edoc_refs:is_top(Ref, Env) of
89		 true -> " target=\"_top\""; % note the initial space
90		 false -> ""
91	     end,
92    lists:flatten(io_lib:fwrite("<a href=\"~ts\"~ts>~ts</a>",
93				[URI, Target, Txt])).
94
95section_macro(S, _Line, _Env) ->
96    S1 = lists:reverse(edoc_lib:strip_space(
97			 lists:reverse(edoc_lib:strip_space(S)))),
98    lists:flatten(io_lib:format("<a href=\"#~ts\">~ts</a>",
99				[edoc_lib:to_label(S1), S1])).
100
101type_macro(S, Line, Env) ->
102    S1 = "t()=" ++ S,
103    Def = edoc_parser:parse_typedef(S1, Line),
104    {#t_typedef{type = T}, _} = Def,
105    Txt = edoc_layout:type(edoc_data:type(T, Env)),
106    lists:flatten(io_lib:fwrite("<code>~ts</code>", [Txt])).
107
108
109%% Expand inline macros in tag content.
110
111expand_tags(Ts, Env, Where) ->
112    Defs = dict:from_list(lists:reverse(Env#env.macros)),
113    expand_tags(Ts, Defs, Env, Where).
114
115expand_tags([#tag{data = Cs, line = L} = T | Ts], Defs, Env, Where) ->
116    [T#tag{data = expand_tag(Cs, L, Defs, Env, Where)}
117     | expand_tags(Ts, Defs, Env, Where)];
118expand_tags([T | Ts], Defs, Env, Where) ->
119    [T | expand_tags(Ts, Defs, Env, Where)];
120expand_tags([], _, _, _) ->
121    [].
122
123expand_tag(Cs, L, Defs, Env, Where) ->
124    case catch {ok, expand_text(Cs, L, Defs, Env, Where)} of
125 	{ok, Cs1} ->
126	    lists:reverse(Cs1);
127 	{'EXIT', R} ->
128	    exit(R);
129	{error, L1, Error} ->
130	    error(L1, Where, Error),
131	    exit(error);
132	Other ->
133	    throw(Other)
134    end.
135
136%% Expand macros in arbitrary lines of text.
137%% The result is in reverse order.
138
139-record(state, {where, env, seen}).
140
141expand_text(Cs, L, Defs, Env, Where) ->
142    St = #state{where = Where,
143		env = Env,
144		seen = sets:new()},
145    expand(Cs, L, Defs, St, []).
146
147%% Inline macro syntax: "{@name content}"
148%%   where 'content' is optional, and separated from 'name' by one or
149%%   more whitespace characters. The content is bound to the '{@?}'
150%%   parameter variable, and the macro definition is expanded and
151%%   substituted for the call. Recursion is detected and reported as an
152%%   error, since there are (currently) no control flow operators.
153%% Escape sequences:
154%%   "@{" -> "{"
155%%   "@}" -> "}"
156%%   "@@" -> "@"
157
158expand([$@, $@ | Cs], L, Defs, St, As) ->
159    expand(Cs, L, Defs, St, [$@ | As]);
160expand([$@, ${ | Cs], L, Defs, St, As) ->
161    expand(Cs, L, Defs, St, [${ | As]);
162expand([$@, $} | Cs], L, Defs, St, As) ->
163    expand(Cs, L, Defs, St, [$} | As]);
164expand([${, $@ | Cs], L, Defs, St, As) ->
165    expand_macro(Cs, L, Defs, St, As);
166expand([$\n = C | Cs], L, Defs, St, As) ->
167    expand(Cs, L + 1, Defs, St, [C | As]);
168expand([C | Cs], L, Defs, St, As) ->
169    expand(Cs, L, Defs, St, [C | As]);
170expand([], _, _, _, As) ->
171    As.
172
173expand_macro(Cs, L, Defs, St, As) ->
174    {M, Cs1, L1} = macro_name(Cs, L),
175    {Arg, Cs2, L2} = macro_content(Cs1, L1),
176    As1 = expand_macro_def(M, Arg, L, Defs, St, As),
177    expand(Cs2, L2, Defs, St, As1).
178
179%% The macro argument (the "content") is expanded in the environment of
180%% the call, and the result is bound to the '{@?}' parameter. The result
181%% of the macro expansion is then expanded again. This allows macro
182%% definitions to contain calls to other macros, avoids name capture of
183%% '{@?}', and makes it easier to write handler functions for special
184%% macros such as '{@link ...}', since the argument is already expanded.
185
186expand_macro_def(M, Arg, L, Defs, St, As) ->
187    Seen = St#state.seen,
188    case sets:is_element(M, Seen) of
189	true ->
190	    throw_error(L, {"recursive macro expansion of {@~s}.",
191			    [M]});
192	false ->
193	    Arg1 = lists:reverse(expand(Arg, L, Defs, St, [])),
194	    Defs1 = dict:store('?', Arg1, Defs),
195	    St1 = St#state{seen = sets:add_element(M, Seen)},
196	    case dict:find(M, Defs) of
197		{ok, Def} ->
198		    Txt = if is_function(Def) ->
199				  Def(Arg1, L, St1#state.env);
200			     is_list(Def) ->
201				  Def
202			  end,
203		    expand(Txt, L, Defs1, St1, As);
204		error ->
205		    warning(L, St1#state.where,
206			    "undefined macro {@~s}.", [M]),
207		    "??"
208	    end
209    end.
210
211%% The macro name ends at the first whitespace or '}' character.  The
212%% content, if any, starts at the next non-whitespace character.
213
214%% See edoc_tags:scan_tag/is_name/1 for details on what is a valid
215%% name. In macro names we also allow '?' as the initial character.
216
217macro_name(Cs, L) ->
218    macro_name(Cs, [], L).
219
220macro_name([C | Cs], As, L) when C >= $a, C =< $z ->
221    macro_name_1(Cs, [C | As], L);
222macro_name([C | Cs], As, L) when C >= $A, C =< $Z ->
223    macro_name_1(Cs, [C | As], L);
224macro_name([C | Cs], As, L) when C >= $\300, C =< $\377,
225				 C =/= $\327, C =/= $\367 ->
226    macro_name_1(Cs, [C | As], L);
227macro_name([$_ | Cs], As, L) ->
228    macro_name_1(Cs, [$_ | As], L);
229macro_name([$? | Cs], As, L) ->
230    macro_name_1(Cs, [$? | As], L);
231macro_name([$\s | _Cs], _As, L) ->
232    throw_error(L, macro_name);
233macro_name([$\t | _Cs], _As, L) ->
234    throw_error(L, macro_name);
235macro_name([$\n | _Cs], _As, L) ->
236    throw_error(L, macro_name);
237macro_name([C | _Cs], As, L) ->
238    throw_error(L, {macro_name, [C | As]});
239macro_name([], _As, L) ->
240    throw_error(L, macro_name).
241
242macro_name_1([C | Cs], As, L) when C >= $a, C =< $z ->
243    macro_name_1(Cs, [C | As], L);
244macro_name_1([C | Cs], As, L) when C >= $A, C =< $Z ->
245    macro_name_1(Cs, [C | As], L);
246macro_name_1([C | Cs], As, L) when C >= $0, C =< $9 ->
247    macro_name_1(Cs, [C | As], L);
248macro_name_1([C | Cs], As, L) when C >= $\300, C =< $\377,
249				   C =/= $\327, C =/= $\367 ->
250    macro_name_1(Cs, [C | As], L);
251macro_name_1([$_ | Cs], As, L) ->
252    macro_name_1(Cs, [$_ | As], L);
253macro_name_1([$\s | Cs], As, L) ->
254    macro_name_2(Cs, As, L);
255macro_name_1([$\t | Cs], As, L) ->
256    macro_name_2(Cs, As, L);
257macro_name_1([$\n | Cs], As, L) ->
258    macro_name_2(Cs, As, L + 1);
259macro_name_1([$} | _] = Cs, As, L) ->
260    macro_name_3(Cs, As, L);
261macro_name_1([C | _Cs], As, L) ->
262    throw_error(L, {macro_name, [C | As]});
263macro_name_1([], _As, L) ->
264    throw_error(L, unterminated_macro).
265
266macro_name_2([$\s | Cs], As, L) ->
267    macro_name_2(Cs, As, L);
268macro_name_2([$\t | Cs], As, L) ->
269    macro_name_2(Cs, As, L);
270macro_name_2([$\n | Cs], As, L) ->
271    macro_name_2(Cs, As, L + 1);
272macro_name_2([_ | _] = Cs, As, L) ->
273    macro_name_3(Cs, As, L);
274macro_name_2([], _As, L) ->
275    throw_error(L, unterminated_macro).
276
277macro_name_3(Cs, As, L) ->
278    {list_to_atom(lists:reverse(As)), Cs, L}.
279
280
281%% The macro content ends at the first non-escaped '}' character that is
282%% not balanced by a corresponding non-escaped '{@' sequence.
283%% Escape sequences are those defined above.
284
285macro_content(Cs, L) ->
286    %% If there is an error, we report the start line, not the end line.
287    case catch {ok, macro_content(Cs, [], L, 0)} of
288	{ok, X} ->
289	    X;
290	{'EXIT', R} ->
291	    exit(R);
292	'end' ->
293	    throw_error(L, unterminated_macro);
294	Other ->
295	    throw(Other)
296    end.
297
298%% @throws 'end'
299
300macro_content([$@, $@ | Cs], As, L, N) ->
301    macro_content(Cs, [$@, $@ | As], L, N);  % escaped '@'
302macro_content([$@, $} | Cs], As, L, N) ->
303    macro_content(Cs, [$}, $@ | As], L, N);  % escaped '}'
304macro_content([$@, ${ | Cs], As, L, N) ->
305    macro_content(Cs, [${, $@ | As], L, N);  % escaped '{'
306macro_content([${, $@ | Cs], As, L, N) ->
307    macro_content(Cs, [$@, ${ | As], L, N + 1);
308macro_content([$} | Cs], As, L, 0) ->
309    {lists:reverse(As), Cs, L};
310macro_content([$} | Cs], As, L, N) ->
311    macro_content(Cs, [$} | As], L, N - 1);
312macro_content([$\n = C | Cs], As, L, N) ->
313    macro_content(Cs, [C | As], L + 1, N);
314macro_content([C | Cs], As, L, N) ->
315    macro_content(Cs, [C | As], L, N);
316macro_content([], _As, _L, _N) ->
317    throw('end').
318
319-type line() :: erl_anno:line().
320-type err()  :: 'unterminated_macro'
321	      | 'macro_name'
322	      | {'macro_name', string()}
323	      | {string(), [string()]}.
324
325-spec throw_error(line(), err()) -> no_return().
326
327throw_error(L, unterminated_macro) ->
328    throw_error(L, {"unexpected end of macro.", []});
329throw_error(L, macro_name) ->
330    throw_error(L, {"missing macro name.", []});
331throw_error(L, {macro_name, S}) ->
332    throw_error(L, {"bad macro name: '@~s...'.", [lists:reverse(S)]});
333throw_error(L, D) ->
334    throw({error, L, D}).
335