1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: jan@swi-prolog.org 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2025, SWI-Prolog Solutions b.v. 7 All rights reserved. 8 9 Redistribution and use in source and binary forms, with or without 10 modification, are permitted provided that the following conditions 11 are met: 12 13 1. Redistributions of source code must retain the above copyright 14 notice, this list of conditions and the following disclaimer. 15 16 2. Redistributions in binary form must reproduce the above copyright 17 notice, this list of conditions and the following disclaimer in 18 the documentation and/or other materials provided with the 19 distribution. 20 21 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 29 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 31 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 POSSIBILITY OF SUCH DAMAGE. 33*/ 34 35:- module(html_decl, 36 [ (html_meta)/1, % +Spec 37 html_no_content/1, % ?Element 38 39 op(1150, fx, html_meta) 40 ]). 41:- autoload(library(apply),[maplist/3,maplist/4]). 42:- if(exists_source(library(http/http_dispatch))). 43:- autoload(library(http/http_dispatch), [http_location_by_id/2]). 44:- endif.

HTML emitter analysis and IDE support

This library supports declaring DCG rules that process HTML terms. It supports the cross-referencer as well as syntax highlighting that is based on library(prolog_colour). */

72html_meta(Spec) :- 73 throw(error(context_error(nodirective, html_meta(Spec)), _)). 74 75html_meta_decls(Var, _, _) :- 76 var(Var), 77 !, 78 instantiation_error(Var). 79html_meta_decls((A,B), (MA,MB), [MH|T]) :- 80 !, 81 html_meta_decl(A, MA, MH), 82 html_meta_decls(B, MB, T). 83html_meta_decls(A, MA, [MH]) :- 84 html_meta_decl(A, MA, MH). 85 86html_meta_decl(Head, MetaHead, 87 html_decl:html_meta_head(GenHead, Module, Head)) :- 88 functor(Head, Name, Arity), 89 functor(GenHead, Name, Arity), 90 prolog_load_context(module, Module), 91 Head =.. [Name|HArgs], 92 maplist(html_meta_decl, HArgs, MArgs), 93 MetaHead =.. [Name|MArgs]. 94 95html_meta_decl(html, :) :- !. 96html_meta_decl(Meta, Meta). 97 98system:term_expansion((:- html_meta(Heads)), 99 [ (:- meta_predicate(Meta)) 100 | MetaHeads 101 ]) :- 102 html_meta_decls(Heads, Meta, MetaHeads). 103 104:- multifile 105 html_meta_head/3. 106 107html_meta_colours(Head, Goal, built_in-Colours) :- 108 Head =.. [_|MArgs], 109 Goal =.. [_|Args], 110 maplist(meta_colours, MArgs, Args, Colours). 111 112meta_colours(html, HTML, Colours) :- 113 !, 114 html_colours(HTML, Colours). 115meta_colours(I, _, Colours) :- 116 integer(I), I>=0, 117 !, 118 Colours = meta(I). 119meta_colours(_, _, classify). 120 121html_meta_called(Head, Goal, Called) :- 122 Head =.. [_|MArgs], 123 Goal =.. [_|Args], 124 meta_called(MArgs, Args, Called, []). 125 126meta_called([], [], Called, Called). 127meta_called([html|MT], [A|AT], Called, Tail) :- 128 !, 129 phrase(called_by(A), Called, Tail1), 130 meta_called(MT, AT, Tail1, Tail). 131meta_called([0|MT], [A|AT], [A|CT0], CT) :- 132 !, 133 meta_called(MT, AT, CT0, CT). 134meta_called([I|MT], [A|AT], [A+I|CT0], CT) :- 135 integer(I), I>0, 136 !, 137 meta_called(MT, AT, CT0, CT). 138meta_called([_|MT], [_|AT], Called, Tail) :- 139 !, 140 meta_called(MT, AT, Called, Tail). 141 142 143 144 /******************************* 145 * PCE EMACS SUPPORT * 146 *******************************/ 147 148:- multifile 149 prolog_colour:goal_colours/2, 150 prolog_colour:style/2, 151 prolog_colour:message//1, 152 prolog:called_by/2, 153 prolog:xref_update_syntax/2. % +Term, +Module 154 155prolog_colour:goal_colours(Goal, Colours) :- 156 ( html_meta_head(Goal, _Module, Head) 157 -> true 158 ; dyn_html_meta_head(Goal, _Module, Head) 159 ), 160 html_meta_colours(Head, Goal, Colours). 161prolog_colour:goal_colours(html_meta(_), 162 built_in-[meta_declarations([html])]). 163 164 % TBD: Check with do_expand! 165html_colours(Var, classify) :- 166 var(Var), 167 !. 168html_colours(\List, html_raw-[list-Colours]) :- 169 is_list(List), 170 !, 171 list_colours(List, Colours). 172html_colours(\_, html_call-[dcg]) :- !. 173html_colours(_:Term, built_in-[classify,Colours]) :- 174 !, 175 html_colours(Term, Colours). 176html_colours(&(Entity), functor-[entity(Entity)]) :- !. 177html_colours(List, list-ListColours) :- 178 List = [_|_], 179 !, 180 list_colours(List, ListColours). 181html_colours(Var=Spec, functor-[classify,SpecColors]) :- 182 var(Var), 183 !, 184 html_colours(Spec, SpecColors). 185html_colours(Format-Args, functor-[FormatColor,ArgsColors]) :- 186 !, 187 format_colours(Format, FormatColor), 188 format_arg_colours(Args, Format, ArgsColors). 189html_colours(Term, TermColours) :- 190 compound(Term), 191 compound_name_arguments(Term, Name, Args), 192 Name \== '.', 193 !, 194 ( Args = [One] 195 -> TermColours = html(Name)-ArgColours, 196 ( html_no_content(Name) 197 -> attr_colours(One, ArgColours) 198 ; html_colours(One, Colours), 199 ArgColours = [Colours] 200 ) 201 ; Args = [AList,Content] 202 -> TermColours = html(Name)-[AColours, Colours], 203 attr_colours(AList, AColours), 204 html_colours(Content, Colours) 205 ; TermColours = error 206 ). 207html_colours(_, classify). 208 209list_colours(Var, classify) :- 210 var(Var), 211 !. 212list_colours([], []). 213list_colours([H0|T0], [H|T]) :- 214 !, 215 html_colours(H0, H), 216 list_colours(T0, T). 217list_colours(Last, Colours) :- % improper list 218 html_colours(Last, Colours). 219 220attr_colours(Var, classify) :- 221 var(Var), 222 !. 223attr_colours([], classify) :- !. 224attr_colours(Term, list-Elements) :- 225 Term = [_|_], 226 !, 227 attr_list_colours(Term, Elements). 228attr_colours(Name=Value, built_in-[html_attribute(Name), VColour]) :- 229 !, 230 attr_value_colour(Value, VColour). 231attr_colours(NS:Term, built_in-[ html_xmlns(NS), 232 html_attribute(Name)-[classify] 233 ]) :- 234 compound(Term), 235 compound_name_arity(Term, Name, 1). 236attr_colours(Term, html_attribute(Name)-[VColour]) :- 237 compound(Term), 238 compound_name_arity(Term, Name, 1), 239 !, 240 Term =.. [Name,Value], 241 attr_value_colour(Value, VColour). 242attr_colours(Name, html_attribute(Name)) :- 243 atom(Name), 244 !. 245attr_colours(Term, classify) :- 246 compound(Term), 247 compound_name_arity(Term, '.', 2), 248 !. 249attr_colours(_, error). 250 251attr_list_colours(Var, classify) :- 252 var(Var), 253 !. 254attr_list_colours([], []). 255attr_list_colours([H0|T0], [H|T]) :- 256 attr_colours(H0, H), 257 attr_list_colours(T0, T). 258 259attr_value_colour(Var, classify) :- 260 var(Var). 261attr_value_colour(location_by_id(ID), sgml_attr_function-[Colour]) :- 262 !, 263 location_id(ID, Colour). 264attr_value_colour(#(ID), sgml_attr_function-[Colour]) :- 265 !, 266 location_id(ID, Colour). 267attr_value_colour(A+B, sgml_attr_function-[CA,CB]) :- 268 !, 269 attr_value_colour(A, CA), 270 attr_value_colour(B, CB). 271attr_value_colour(encode(_), sgml_attr_function-[classify]) :- !. 272attr_value_colour(Atom, classify) :- 273 atomic(Atom), 274 !. 275attr_value_colour([_|_], classify) :- !. 276attr_value_colour(_Fmt-_Args, classify) :- !. 277attr_value_colour(Term, classify) :- 278 compound(Term), 279 compound_name_arity(Term, '.', 2), 280 !. 281attr_value_colour(_, error). 282 283location_id(ID, classify) :- 284 var(ID), 285 !. 286:- if(current_predicate(http_location_for_id/1)). 287location_id(ID, Class) :- 288 ( catch(http_location_by_id(ID, Location), _, fail) 289 -> Class = http_location_for_id(Location) 290 ; Class = http_no_location_for_id(ID) 291 ). 292:- endif. 293location_id(_, classify). 294 295format_colours(Format, format_string) :- atom(Format), !. 296format_colours(Format, format_string) :- string(Format), !. 297format_colours(_Format, type_error(text)). 298 299format_arg_colours(Args, _Format, classify) :- is_list(Args), !. 300format_arg_colours(_, _, type_error(list)).

306html_no_content(area). 307html_no_content(base). 308html_no_content(br). 309html_no_content(col). 310html_no_content(embed). 311html_no_content(hr). 312html_no_content(img). 313html_no_content(input). 314html_no_content(link). 315html_no_content(meta). 316html_no_content(param). 317html_no_content(source). 318html_no_content(track). 319html_no_content(wbr). 320 321:- op(990, xfx, :=). % allow compiling without XPCE 322:- op(200, fy, @). 323 324prolog_colour:style(html(_), [colour(magenta4), bold(true)]). 325prolog_colour:style(entity(_), [colour(magenta4)]). 326prolog_colour:style(html_attribute(_), [colour(magenta4)]). 327prolog_colour:style(html_xmlns(_), [colour(magenta4)]). 328prolog_colour:style(format_string(_), [colour(magenta4)]). 329prolog_colour:style(sgml_attr_function, [colour(blue)]). 330prolog_colour:style(http_location_for_id(_), [bold(true)]). 331prolog_colour:style(http_no_location_for_id(_), [colour(red), bold(true)]). 332 333 334prolog_colour:message(html(Element)) --> 335 [ '~w: SGML element'-[Element] ]. 336prolog_colour:message(entity(Entity)) --> 337 [ '~w: SGML entity'-[Entity] ]. 338prolog_colour:message(html_attribute(Attr)) --> 339 [ '~w: SGML attribute'-[Attr] ]. 340prolog_colour:message(sgml_attr_function) --> 341 [ 'SGML Attribute function'-[] ]. 342prolog_colour:message(http_location_for_id(Location)) --> 343 [ 'ID resolves to ~w'-[Location] ]. 344prolog_colour:message(http_no_location_for_id(ID)) --> 345 [ '~w: no such ID'-[ID] ]. 346 347 348 /******************************* 349 * XREF HTML_META * 350 *******************************/ 351 352:- dynamic dyn_html_meta_head/3 as volatile. 353 354prolog:xref_update_syntax((:- html_meta(Decls)), Module) :- 355 dyn_meta_heads(Decls, Module). 356 357dyn_meta_heads((A,B), Module) => 358 dyn_meta_heads(A, Module), 359 dyn_meta_heads(B, Module). 360dyn_meta_heads(QHead, Module) => 361 strip_module(Module:QHead, M, Head), 362 most_general_goal(Head, Gen), 363 retractall(dyn_html_meta_head(Gen, M, _)), 364 asserta(dyn_html_meta_head(Gen, M, Head)). 365 366% prolog:called_by(+Goal, -Called) 367% 368% Hook into library(pce_prolog_xref). Called is a list of callable 369% or callable+N to indicate (DCG) arglist extension. 370 371prolog:called_by(Goal, Called) :- 372 ( html_meta_head(Goal, _Module, Head) 373 -> true 374 ; dyn_html_meta_head(Goal, _Module, Head) 375 ), 376 html_meta_called(Head, Goal, Called). 377 378called_by(Term) --> 379 called_by(Term, _). 380 381called_by(Var, _) --> 382 { var(Var) }, 383 !, 384 []. 385called_by(\G, M) --> 386 !, 387 ( { is_list(G) } 388 -> called_by(G, M) 389 ; {atom(M)} 390 -> [(M:G)+2] 391 ; [G+2] 392 ). 393called_by([], _) --> 394 !, 395 []. 396called_by([H|T], M) --> 397 !, 398 called_by(H, M), 399 called_by(T, M). 400called_by(M:Term, _) --> 401 !, 402 ( {atom(M)} 403 -> called_by(Term, M) 404 ; [] 405 ). 406called_by(Var=Term, M) --> 407 { var(Var) }, 408 called_by(Term, M). 409called_by(Term, M) --> 410 { compound(Term), 411 !, 412 Term =.. [_|Args] 413 }, 414 called_by(Args, M). 415called_by(_, _) --> 416 []