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1 | /*============================================================================= | |
2 | Copyright (c) 2001-2011 Joel de Guzman | |
3 | Copyright (c) 2001-2011 Hartmut Kaiser | |
4 | Copyright (c) 2010-2011 Bryce Lelbach | |
5 | ||
6 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
7 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
8 | =============================================================================*/ | |
9 | #if !defined(BOOST_SPIRIT_UTREE) | |
10 | #define BOOST_SPIRIT_UTREE | |
11 | ||
12 | #include <cstddef> | |
13 | #include <algorithm> | |
14 | #include <string> | |
15 | #include <iostream> | |
16 | #include <ios> | |
17 | #include <sstream> | |
18 | #include <typeinfo> | |
19 | ||
20 | #include <boost/io/ios_state.hpp> | |
21 | #include <boost/integer.hpp> | |
22 | #include <boost/throw_exception.hpp> | |
23 | #include <boost/assert.hpp> | |
24 | #include <boost/noncopyable.hpp> | |
25 | #include <boost/iterator/iterator_facade.hpp> | |
26 | #include <boost/range/iterator_range.hpp> | |
27 | #include <boost/type_traits/remove_pointer.hpp> | |
28 | #include <boost/type_traits/is_polymorphic.hpp> | |
29 | #include <boost/utility/enable_if.hpp> | |
30 | #include <boost/utility/result_of.hpp> | |
31 | #include <boost/ref.hpp> | |
32 | #include <boost/config.hpp> | |
33 | ||
34 | #include <boost/spirit/home/support/utree/detail/utree_detail1.hpp> | |
35 | ||
36 | #if defined(BOOST_MSVC) | |
37 | # pragma warning(push) | |
38 | # pragma warning(disable: 4804) | |
39 | # pragma warning(disable: 4805) | |
40 | # pragma warning(disable: 4244) | |
41 | #endif | |
42 | ||
43 | namespace boost { namespace spirit | |
44 | { | |
45 | //[utree_exceptions | |
46 | /*` All exceptions thrown by utree are derived from utree_exception. */ | |
47 | struct BOOST_SYMBOL_VISIBLE utree_exception : std::exception {}; | |
48 | ||
49 | /*`The `bad_type_exception` is thrown whenever somebody calls a member | |
50 | function, which applies to certain stored utree_type's only, but this | |
51 | precondition is violated as the `utree` instance holds some other type. | |
52 | */ | |
53 | struct bad_type_exception /*: utree_exception*/; | |
54 | ||
55 | /*`The `empty_exception` is thrown whenever a precondition of a list | |
56 | or range utree method is violated due to the list or range being empty. | |
57 | */ | |
58 | struct empty_exception /*: utree_exception*/; | |
59 | //] | |
60 | ||
61 | //[utree_types | |
62 | /*`Each instance of an `utree` data structure can store exactly one of the | |
63 | following data types at a time: | |
64 | */ | |
65 | struct utree_type | |
66 | { | |
67 | enum info | |
68 | { | |
69 | invalid_type, // the utree has not been initialized (it's | |
70 | // default constructed) | |
71 | nil_type, // nil is the sentinel (empty) utree type. | |
72 | list_type, // A doubly linked list of utrees. | |
73 | range_type, // A range of list::iterators. | |
74 | reference_type, // A reference to another utree. | |
75 | any_type, // A pointer or reference to any C++ type. | |
76 | function_type, // A utree holding a stored_function<F> object, | |
77 | // where F is an unary function object taking a | |
78 | // utree as it's parameter and returning a | |
79 | // utree. | |
80 | ||
81 | // numeric atoms | |
82 | bool_type, // An utree holding a boolean value | |
83 | int_type, // An utree holding a integer (int) value | |
84 | double_type, // An utree holding a floating point (double) value | |
85 | ||
86 | // text atoms (utf8) | |
87 | string_type, // An UTF-8 string | |
88 | string_range_type, // A pair of iterators into an UTF-8 string | |
89 | symbol_type, // An UTF-8 symbol name | |
90 | ||
91 | binary_type // Arbitrary binary data | |
92 | }; | |
93 | typedef boost::uint_t<sizeof(info)*8>::exact exact_integral_type; | |
94 | typedef boost::uint_t<sizeof(info)*8>::fast fast_integral_type; | |
95 | }; | |
96 | //] | |
97 | ||
98 | // streaming operator for utree types - essential for diagnostics | |
99 | inline std::ostream& operator<<(std::ostream& out, utree_type::info t) | |
100 | { | |
101 | boost::io::ios_all_saver saver(out); | |
102 | switch (t) { | |
103 | case utree_type::invalid_type: { out << "invalid"; break; } | |
104 | case utree_type::nil_type: { out << "nil"; break; } | |
105 | case utree_type::list_type: { out << "list"; break; } | |
106 | case utree_type::range_type: { out << "range"; break; } | |
107 | case utree_type::reference_type: { out << "reference"; break; } | |
108 | case utree_type::any_type: { out << "any"; break; } | |
109 | case utree_type::function_type: { out << "function"; break; } | |
110 | case utree_type::bool_type: { out << "bool"; break; } | |
111 | case utree_type::int_type: { out << "int"; break; } | |
112 | case utree_type::double_type: { out << "double"; break; } | |
113 | case utree_type::string_type: { out << "string"; break; } | |
114 | case utree_type::string_range_type: { out << "string_range"; break; } | |
115 | case utree_type::symbol_type: { out << "symbol"; break; } | |
116 | case utree_type::binary_type: { out << "binary"; break; } | |
117 | default: { out << "unknown"; break; } | |
118 | } | |
119 | out << std::hex << "[0x" | |
120 | << static_cast<utree_type::fast_integral_type>(t) << "]"; | |
121 | return out; | |
122 | } | |
123 | ||
124 | struct bad_type_exception : utree_exception | |
125 | { | |
126 | std::string msg; | |
127 | ||
128 | bad_type_exception(char const* error, utree_type::info got) | |
129 | : msg() | |
130 | { | |
131 | std::ostringstream oss; | |
132 | oss << "utree: " << error | |
133 | << " (got utree type '" << got << "')"; | |
134 | msg = oss.str(); | |
135 | } | |
136 | ||
137 | bad_type_exception(char const* error, utree_type::info got1, | |
138 | utree_type::info got2) | |
139 | : msg() | |
140 | { | |
141 | std::ostringstream oss; | |
142 | oss << "utree: " << error | |
143 | << " (got utree types '" << got1 << "' and '" << got2 << "')"; | |
144 | msg = oss.str(); | |
145 | } | |
146 | ||
147 | virtual ~bad_type_exception() BOOST_NOEXCEPT_OR_NOTHROW {} | |
148 | ||
149 | virtual char const* what() const BOOST_NOEXCEPT_OR_NOTHROW | |
150 | { return msg.c_str(); } | |
151 | }; | |
152 | ||
153 | struct empty_exception : utree_exception | |
154 | { | |
155 | char const* msg; | |
156 | ||
157 | empty_exception(char const* error) : msg(error) {} | |
158 | ||
159 | virtual ~empty_exception() BOOST_NOEXCEPT_OR_NOTHROW {} | |
160 | ||
161 | virtual char const* what() const BOOST_NOEXCEPT_OR_NOTHROW | |
162 | { return msg; } | |
163 | }; | |
164 | ||
165 | /////////////////////////////////////////////////////////////////////////// | |
166 | // A typed string with parametric Base storage. The storage can be any | |
167 | // range or (stl container) of chars. | |
168 | /////////////////////////////////////////////////////////////////////////// | |
169 | template <typename Base, utree_type::info type_> | |
170 | struct basic_string : Base | |
171 | { | |
172 | static utree_type::info const type = type_; | |
173 | ||
174 | basic_string() | |
175 | : Base() {} | |
176 | ||
177 | basic_string(Base const& base) | |
178 | : Base(base) {} | |
179 | ||
180 | template <typename Iterator> | |
181 | basic_string(Iterator bits, std::size_t len) | |
182 | : Base(bits, bits + len) {} | |
183 | ||
184 | template <typename Iterator> | |
185 | basic_string(Iterator first, Iterator last) | |
186 | : Base(first, last) {} | |
187 | ||
188 | basic_string& operator=(basic_string const& other) | |
189 | { | |
190 | Base::operator=(other); | |
191 | return *this; | |
192 | } | |
193 | ||
194 | basic_string& operator=(Base const& other) | |
195 | { | |
196 | Base::operator=(other); | |
197 | return *this; | |
198 | } | |
199 | }; | |
200 | ||
201 | //[utree_strings | |
202 | /*`The `utree` string types described below are used by the `utree` API | |
203 | only. These are not used to store information in the `utree` itself. | |
204 | Their purpose is to refer to different internal `utree` node types | |
205 | only. For instance, creating a `utree` from a binary data type will | |
206 | create a `binary_type` utree node (see above). | |
207 | */ | |
208 | /*`The binary data type can be represented either verbatim as a sequence | |
209 | of bytes or as a pair of iterators into some other stored binary data | |
210 | sequence. Use this string type to access/create a `binary_type` `utree`. | |
211 | */ | |
212 | typedef basic_string< | |
213 | boost::iterator_range<char const*>, utree_type::binary_type | |
214 | > binary_range_type; | |
215 | typedef basic_string< | |
216 | std::string, utree_type::binary_type | |
217 | > binary_string_type; | |
218 | ||
219 | /*`The UTF-8 string can be represented either verbatim as a sequence of | |
220 | characters or as a pair of iterators into some other stored binary data | |
221 | sequence. Use this string type to access/create a `string_type` `utree`. | |
222 | */ | |
223 | typedef basic_string< | |
224 | boost::iterator_range<char const*>, utree_type::string_type | |
225 | > utf8_string_range_type; | |
226 | typedef basic_string< | |
227 | std::string, utree_type::string_type | |
228 | > utf8_string_type; | |
229 | ||
230 | /*`The UTF-8 symbol can be represented either verbatim as a sequence of | |
231 | characters or as a pair of iterators into some other stored binary data | |
232 | sequence. Use this string type to access/create a `symbol_type` `utree`. | |
233 | */ | |
234 | typedef basic_string< | |
235 | boost::iterator_range<char const*>, utree_type::symbol_type | |
236 | > utf8_symbol_range_type; | |
237 | typedef basic_string< | |
238 | std::string, utree_type::symbol_type | |
239 | > utf8_symbol_type; | |
240 | //] | |
241 | ||
242 | /////////////////////////////////////////////////////////////////////////// | |
243 | // Our function type | |
244 | /////////////////////////////////////////////////////////////////////////// | |
245 | class utree; | |
246 | ||
247 | //[utree_function_object_interface | |
248 | struct function_base | |
249 | { | |
250 | virtual ~function_base() {} | |
251 | virtual utree operator()(utree const& env) const = 0; | |
252 | virtual utree operator()(utree& env) const = 0; | |
253 | ||
254 | // Calling f.clone() must return a newly allocated function_base | |
255 | // instance that is equal to f. | |
256 | virtual function_base* clone() const = 0; | |
257 | }; | |
258 | ||
259 | template <typename F> | |
260 | struct stored_function : function_base | |
261 | { | |
262 | F f; | |
263 | stored_function(F f = F()); | |
264 | virtual ~stored_function(); | |
265 | virtual utree operator()(utree const& env) const; | |
266 | virtual utree operator()(utree& env) const; | |
267 | virtual function_base* clone() const; | |
268 | }; | |
269 | ||
270 | template <typename F> | |
271 | struct referenced_function : function_base | |
272 | { | |
273 | F& f; | |
274 | referenced_function(F& f); | |
275 | virtual ~referenced_function(); | |
276 | virtual utree operator()(utree const& env) const; | |
277 | virtual utree operator()(utree& env) const; | |
278 | virtual function_base* clone() const; | |
279 | }; | |
280 | //] | |
281 | ||
282 | /////////////////////////////////////////////////////////////////////////// | |
283 | // Shallow tag. Instructs utree to hold an iterator_range | |
284 | // as-is without deep copying the range. | |
285 | /////////////////////////////////////////////////////////////////////////// | |
286 | struct shallow_tag {}; | |
287 | shallow_tag const shallow = {}; | |
288 | ||
289 | /////////////////////////////////////////////////////////////////////////// | |
290 | // A void* plus type_info | |
291 | /////////////////////////////////////////////////////////////////////////// | |
292 | class any_ptr | |
293 | { | |
294 | public: | |
295 | template <typename Ptr> | |
296 | typename boost::disable_if< | |
297 | boost::is_polymorphic< | |
298 | typename boost::remove_pointer<Ptr>::type>, | |
299 | Ptr>::type | |
300 | get() const | |
301 | { | |
302 | if (*i == typeid(Ptr)) | |
303 | { | |
304 | return static_cast<Ptr>(p); | |
305 | } | |
306 | boost::throw_exception(std::bad_cast()); | |
307 | } | |
308 | ||
309 | template <typename T> | |
310 | any_ptr(T* p) | |
311 | : p(p), i(&typeid(T*)) | |
312 | {} | |
313 | ||
314 | friend bool operator==(any_ptr const& a, any_ptr const& b) | |
315 | { | |
316 | return (a.p == b.p) && (*a.i == *b.i); | |
317 | } | |
318 | ||
319 | private: | |
320 | // constructor is private | |
321 | any_ptr(void* p, std::type_info const* i) | |
322 | : p(p), i(i) {} | |
323 | ||
324 | template <typename UTreeX, typename UTreeY> | |
325 | friend struct detail::visit_impl; | |
326 | ||
327 | friend class utree; | |
328 | ||
329 | void* p; | |
330 | std::type_info const* i; | |
331 | }; | |
332 | ||
333 | //[utree | |
334 | class utree { | |
335 | public: | |
336 | /////////////////////////////////////////////////////////////////////// | |
337 | // The invalid type | |
338 | struct invalid_type {}; | |
339 | ||
340 | /////////////////////////////////////////////////////////////////////// | |
341 | // The nil type | |
342 | struct nil_type {}; | |
343 | ||
344 | /////////////////////////////////////////////////////////////////////// | |
345 | // The list type, this can be used to initialize an utree to hold an | |
346 | // empty list | |
347 | struct list_type; | |
348 | ||
349 | //[utree_container_types | |
350 | typedef utree value_type; | |
351 | typedef utree& reference; | |
352 | typedef utree const& const_reference; | |
353 | typedef std::ptrdiff_t difference_type; | |
354 | typedef std::size_t size_type; | |
355 | ||
356 | typedef detail::list::node_iterator<utree> iterator; | |
357 | typedef detail::list::node_iterator<utree const> const_iterator; | |
358 | //] | |
359 | ||
360 | typedef detail::list::node_iterator<boost::reference_wrapper<utree> > | |
361 | ref_iterator; | |
362 | ||
363 | typedef boost::iterator_range<iterator> range; | |
364 | typedef boost::iterator_range<const_iterator> const_range; | |
365 | ||
366 | // dtor | |
367 | ~utree(); | |
368 | ||
369 | //////////////////////////////////////////////////////////////////////// | |
370 | //[utree_initialization | |
371 | /*`A `utree` can be constructed or initialized from a wide range of | |
372 | data types, allowing to create `utree` instances for every | |
373 | possible node type (see the description of `utree_type::info` above). | |
374 | For this reason it exposes a constructor and an assignment operator | |
375 | for each of the allowed node types as shown below. All constructors | |
376 | are non-explicit on purpose, allowing to use an utree instance as | |
377 | the attribute to almost any Qi parser. | |
378 | */ | |
379 | // This constructs an `invalid_type` node. When used in places | |
380 | // where a boost::optional is expected (i.e. as an attribute for the | |
381 | // optional component), this represents the 'empty' state. | |
382 | utree(invalid_type = invalid_type()); | |
383 | ||
384 | // This initializes a `nil_type` node, which represents a valid, | |
385 | // 'initialized empty' utree (different from invalid_type!). | |
386 | utree(nil_type); | |
387 | reference operator=(nil_type); | |
388 | ||
389 | // This initializes a `boolean_type` node, which can hold 'true' or | |
390 | // 'false' only. | |
391 | explicit utree(bool); | |
392 | reference operator=(bool); | |
393 | ||
394 | // This initializes an `integer_type` node, which can hold arbitrary | |
395 | // integers. For convenience these functions are overloaded for signed | |
396 | // and unsigned integer types. | |
397 | utree(unsigned int); | |
398 | utree(int); | |
399 | reference operator=(unsigned int); | |
400 | reference operator=(int); | |
401 | ||
402 | // This initializes a `double_type` node, which can hold arbitrary | |
403 | // floating point (double) values. | |
404 | utree(double); | |
405 | reference operator=(double); | |
406 | ||
407 | // This initializes a `string_type` node, which can hold a narrow | |
408 | // character sequence (usually an UTF-8 string). | |
409 | utree(char); | |
410 | utree(char const*); | |
411 | utree(char const*, std::size_t); | |
412 | utree(std::string const&); | |
413 | reference operator=(char); | |
414 | reference operator=(char const*); | |
415 | reference operator=(std::string const&); | |
416 | ||
417 | // This constructs a `string_range_type` node, which does not copy the | |
418 | // data but stores the iterator range to the character sequence the | |
419 | // range has been initialized from. | |
420 | utree(utf8_string_range_type const&, shallow_tag); | |
421 | ||
422 | // This initializes a `reference_type` node, which holds a reference to | |
423 | // another utree node. All operations on such a node are automatically | |
424 | // forwarded to the referenced utree instance. | |
425 | utree(boost::reference_wrapper<utree>); | |
426 | reference operator=(boost::reference_wrapper<utree>); | |
427 | ||
428 | // This initializes an `any_type` node, which can hold a pointer to an | |
429 | // instance of any type together with the typeid of that type. When | |
430 | // accessing that pointer the typeid will be checked, causing a | |
431 | // std::bad_cast to be thrown if the typeids do not match. | |
432 | utree(any_ptr const&); | |
433 | reference operator=(any_ptr const&); | |
434 | ||
435 | // This initializes a `range_type` node, which holds an utree list node | |
436 | // the elements of which are copy constructed (assigned) from the | |
437 | // elements referenced by the given range of iterators. | |
438 | template <class Iterator> | |
439 | utree(boost::iterator_range<Iterator>); | |
440 | template <class Iterator> | |
441 | reference operator=(boost::iterator_range<Iterator>); | |
442 | ||
443 | // This initializes a `function_type` node from a polymorphic function | |
444 | // object pointer (takes ownership) or reference. | |
445 | utree(function_base const&); | |
446 | reference operator=(function_base const&); | |
447 | utree(function_base*); | |
448 | reference operator=(function_base*); | |
449 | ||
450 | // This initializes either a `string_type`, a `symbol_type`, or a | |
451 | // `binary_type` node (depending on the template parameter `type_`), | |
452 | // which will hold the corresponding narrow character sequence (usually | |
453 | // an UTF-8 string). | |
454 | template <class Base, utree_type::info type_> | |
455 | utree(basic_string<Base, type_> const&); | |
456 | template <class Base, utree_type::info type_> | |
457 | reference operator=(basic_string<Base, type_> const&); | |
458 | //] | |
459 | ||
460 | // copy | |
461 | utree(const_reference); | |
462 | reference operator=(const_reference); | |
463 | ||
464 | // range | |
465 | utree(range, shallow_tag); | |
466 | utree(const_range, shallow_tag); | |
467 | ||
468 | // assign dispatch | |
469 | template <class Iterator> | |
470 | void assign(Iterator, Iterator); | |
471 | ||
472 | //////////////////////////////////////////////////////////////////////// | |
473 | ||
474 | //////////////////////////////////////////////////////////////////////// | |
475 | // function object visitation interface | |
476 | ||
477 | // single dispatch | |
478 | template <class F> | |
479 | typename boost::result_of<F(utree const&)>::type | |
480 | static visit(utree const&, F); | |
481 | ||
482 | template <class F> | |
483 | typename boost::result_of<F(utree&)>::type | |
484 | static visit(utree&, F); | |
485 | ||
486 | // double dispatch | |
487 | template <class F> | |
488 | typename boost::result_of<F(utree const&, utree const&)>::type | |
489 | static visit(utree const&, utree const&, F); | |
490 | ||
491 | template <class F> | |
492 | typename boost::result_of<F(utree&, utree const&)>::type | |
493 | static visit(utree&, utree const&, F); | |
494 | ||
495 | template <class F> | |
496 | typename boost::result_of<F(utree const&, utree&)>::type | |
497 | static visit(utree const&, utree&, F); | |
498 | ||
499 | template <class F> | |
500 | typename boost::result_of<F(utree&, utree&)>::type | |
501 | static visit(utree&, utree&, F); | |
502 | ||
503 | //////////////////////////////////////////////////////////////////////// | |
504 | ||
505 | /////////////////////////////////////////////////////////////////////// | |
506 | //[utree_container_functions | |
507 | // STL Container interface | |
508 | ||
509 | // insertion | |
510 | template <class T> | |
511 | void push_back(T const&); | |
512 | template <class T> | |
513 | void push_front(T const&); | |
514 | template <class T> | |
515 | iterator insert(iterator, T const&); | |
516 | template <class T> | |
517 | void insert(iterator, std::size_t, T const&); | |
518 | template <class Iterator> | |
519 | void insert(iterator, Iterator, Iterator); | |
520 | ||
521 | // erasure | |
522 | void pop_front(); | |
523 | void pop_back(); | |
524 | iterator erase(iterator); | |
525 | iterator erase(iterator, iterator); | |
526 | ||
527 | // front access | |
528 | reference front(); | |
529 | const_reference front() const; | |
530 | iterator begin(); | |
531 | const_iterator begin() const; | |
532 | ref_iterator ref_begin(); | |
533 | ||
534 | // back access | |
535 | reference back(); | |
536 | const_reference back() const; | |
537 | iterator end(); | |
538 | const_iterator end() const; | |
539 | ref_iterator ref_end(); | |
540 | //] | |
541 | ||
542 | // This clears the utree instance and resets its type to `invalid_type` | |
543 | void clear(); | |
544 | ||
545 | void swap(utree&); | |
546 | ||
547 | bool empty() const; | |
548 | ||
549 | size_type size() const; | |
550 | /*`[warning `size()` has O(n) complexity on `utree` ranges. On utree | |
551 | lists, it has O(1) complexity.]`*/ | |
552 | ||
553 | //////////////////////////////////////////////////////////////////////// | |
554 | ||
555 | //[utree_variant_functions | |
556 | // return the data type (`utree_type::info`) of the currently stored | |
557 | // data item | |
558 | utree_type::info which() const; | |
559 | ||
560 | // access the currently stored data in a type safe manner, this will | |
561 | // throw a `std::bad_cast()` if the currently stored data item is not | |
562 | // default convertible to `T`. | |
563 | template <class T> | |
564 | T get() const; | |
565 | //] | |
566 | ||
567 | reference deref(); | |
568 | const_reference deref() const; | |
569 | ||
570 | short tag() const; | |
571 | void tag(short); | |
572 | ||
573 | utree eval(utree const&) const; | |
574 | utree eval(utree&) const; | |
575 | ||
576 | utree operator() (utree const&) const; | |
577 | utree operator() (utree&) const; | |
578 | //<- | |
579 | protected: | |
580 | void ensure_list_type(char const* failed_in = "ensure_list_type()"); | |
581 | ||
582 | private: | |
583 | typedef utree_type type; | |
584 | ||
585 | template <class UTreeX, class UTreeY> | |
586 | friend struct detail::visit_impl; | |
587 | friend struct detail::index_impl; | |
588 | ||
589 | type::info get_type() const; | |
590 | void set_type(type::info); | |
591 | void free(); | |
592 | void copy(const_reference); | |
593 | ||
594 | union { | |
595 | detail::fast_string s; | |
596 | detail::list l; | |
597 | detail::range r; | |
598 | detail::string_range sr; | |
599 | detail::void_ptr v; | |
600 | bool b; | |
601 | int i; | |
602 | double d; | |
603 | utree* p; | |
604 | function_base* pf; | |
605 | }; | |
606 | //-> | |
607 | }; | |
608 | //] | |
609 | ||
610 | //[utree_tuple_interface | |
611 | /*<-*/inline/*->*/ | |
612 | utree::reference get(utree::reference, utree::size_type); | |
613 | /*<-*/inline/*->*/ | |
614 | utree::const_reference get(utree::const_reference, utree::size_type); | |
615 | /*`[warning `get()` has O(n) complexity.]`*/ | |
616 | //] | |
617 | ||
618 | struct utree::list_type : utree | |
619 | { | |
620 | using utree::operator=; | |
621 | ||
622 | list_type() : utree() { ensure_list_type("list_type()"); } | |
623 | ||
624 | template <typename T0> | |
625 | list_type(T0 t0) : utree(t0) {} | |
626 | ||
627 | template <typename T0, typename T1> | |
628 | list_type(T0 t0, T1 t1) : utree(t0, t1) {} | |
629 | }; | |
630 | ||
631 | /////////////////////////////////////////////////////////////////////////// | |
632 | // predefined instances for singular types | |
633 | utree::invalid_type const invalid = {}; | |
634 | utree::nil_type const nil = {}; | |
635 | utree::list_type const empty_list = utree::list_type(); | |
636 | }} | |
637 | ||
638 | #if defined(BOOST_MSVC) | |
639 | #pragma warning(pop) | |
640 | #endif | |
641 | ||
642 | #endif | |
643 |