3 * Implementation of GiNaC's light-weight expression handles. */
6 * GiNaC Copyright (C) 1999-2005 Johannes Gutenberg University Mainz, Germany
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
33 #include "relational.h"
34 #include "input_lexer.h"
46 // non-virtual functions in this class
51 /** Print expression to stream. The formatting of the output is determined
52 * by the kind of print_context object that is passed. Possible formattings
53 * include ginsh-parsable output (the default), tree-like output for
54 * debugging, and C++ source.
55 * @see print_context */
56 void ex::print(const print_context & c, unsigned level) const
61 /** Little wrapper arount print to be called within a debugger. */
62 void ex::dbgprint() const
67 /** Little wrapper arount printtree to be called within a debugger. */
68 void ex::dbgprinttree() const
73 ex ex::expand(unsigned options) const
75 if (options == 0 && (bp->flags & status_flags::expanded)) // The "expanded" flag only covers the standard options; someone might want to re-expand with different options
78 return bp->expand(options);
81 /** Compute partial derivative of an expression.
83 * @param s symbol by which the expression is derived
84 * @param nth order of derivative (default 1)
85 * @return partial derivative as a new expression */
86 ex ex::diff(const symbol & s, unsigned nth) const
91 return bp->diff(s, nth);
94 /** Check whether expression matches a specified pattern. */
95 bool ex::match(const ex & pattern) const
98 return bp->match(pattern, repl_lst);
101 /** Find all occurrences of a pattern. The found matches are appended to
102 * the "found" list. If the expression itself matches the pattern, the
103 * children are not further examined. This function returns true when any
104 * matches were found. */
105 bool ex::find(const ex & pattern, lst & found) const
107 if (match(pattern)) {
113 bool any_found = false;
114 for (size_t i=0; i<nops(); i++)
115 if (op(i).find(pattern, found))
120 /** Substitute objects in an expression (syntactic substitution) and return
121 * the result as a new expression. */
122 ex ex::subs(const lst & ls, const lst & lr, unsigned options) const
124 GINAC_ASSERT(ls.nops() == lr.nops());
126 // Convert the lists to a map
128 for (lst::const_iterator its = ls.begin(), itr = lr.begin(); its != ls.end(); ++its, ++itr) {
129 m.insert(std::make_pair(*its, *itr));
131 // Search for products and powers in the expressions to be substituted
132 // (for an optimization in expairseq::subs())
133 if (is_exactly_a<mul>(*its) || is_exactly_a<power>(*its))
134 options |= subs_options::pattern_is_product;
136 if (!(options & subs_options::pattern_is_product))
137 options |= subs_options::pattern_is_not_product;
139 return bp->subs(m, options);
142 /** Substitute objects in an expression (syntactic substitution) and return
143 * the result as a new expression. There are two valid types of
144 * replacement arguments: 1) a relational like object==ex and 2) a list of
145 * relationals lst(object1==ex1,object2==ex2,...). */
146 ex ex::subs(const ex & e, unsigned options) const
148 if (e.info(info_flags::relation_equal)) {
150 // Argument is a relation: convert it to a map
152 const ex & s = e.op(0);
153 m.insert(std::make_pair(s, e.op(1)));
155 if (is_exactly_a<mul>(s) || is_exactly_a<power>(s))
156 options |= subs_options::pattern_is_product;
158 options |= subs_options::pattern_is_not_product;
160 return bp->subs(m, options);
162 } else if (e.info(info_flags::list)) {
164 // Argument is a list: convert it to a map
166 GINAC_ASSERT(is_a<lst>(e));
167 for (lst::const_iterator it = ex_to<lst>(e).begin(); it != ex_to<lst>(e).end(); ++it) {
169 if (!r.info(info_flags::relation_equal))
170 throw(std::invalid_argument("basic::subs(ex): argument must be a list of equations"));
171 const ex & s = r.op(0);
172 m.insert(std::make_pair(s, r.op(1)));
174 // Search for products and powers in the expressions to be substituted
175 // (for an optimization in expairseq::subs())
176 if (is_exactly_a<mul>(s) || is_exactly_a<power>(s))
177 options |= subs_options::pattern_is_product;
179 if (!(options & subs_options::pattern_is_product))
180 options |= subs_options::pattern_is_not_product;
182 return bp->subs(m, options);
185 throw(std::invalid_argument("ex::subs(ex): argument must be a relation_equal or a list"));
188 /** Traverse expression tree with given visitor, preorder traversal. */
189 void ex::traverse_preorder(visitor & v) const
194 for (size_t i = 0; i < n; ++i)
195 op(i).traverse_preorder(v);
198 /** Traverse expression tree with given visitor, postorder traversal. */
199 void ex::traverse_postorder(visitor & v) const
202 for (size_t i = 0; i < n; ++i)
203 op(i).traverse_postorder(v);
208 /** Return modifyable operand/member at position i. */
209 ex & ex::let_op(size_t i)
212 return bp->let_op(i);
215 ex & ex::operator[](const ex & index)
221 ex & ex::operator[](size_t i)
227 /** Left hand side of relational expression. */
230 if (!is_a<relational>(*this))
231 throw std::runtime_error("ex::lhs(): not a relation");
235 /** Right hand side of relational expression. */
238 if (!is_a<relational>(*this))
239 throw std::runtime_error("ex::rhs(): not a relation");
245 /** Make this ex writable (if more than one ex handle the same basic) by
246 * unlinking the object and creating an unshared copy of it. */
247 void ex::makewriteable()
249 GINAC_ASSERT(bp->flags & status_flags::dynallocated);
251 GINAC_ASSERT(bp->get_refcount() == 1);
254 /** Share equal objects between expressions.
255 * @see ex::compare(const ex &) */
256 void ex::share(const ex & other) const
258 if ((bp->flags | other.bp->flags) & status_flags::not_shareable)
261 if (bp->get_refcount() <= other.bp->get_refcount())
267 /** Helper function for the ex-from-basic constructor. This is where GiNaC's
268 * automatic evaluator and memory management are implemented.
269 * @see ex::ex(const basic &) */
270 ptr<basic> ex::construct_from_basic(const basic & other)
272 if (!(other.flags & status_flags::evaluated)) {
274 // The object is not yet evaluated, so call eval() to evaluate
275 // the top level. This will return either
276 // a) the original object with status_flags::evaluated set (when the
277 // eval() implementation calls hold())
279 // b) a different expression.
281 // eval() returns an ex, not a basic&, so this will go through
282 // construct_from_basic() a second time. In case a) we end up in
283 // the "else" branch below. In case b) we end up here again and
284 // apply eval() once more. The recursion stops when eval() calls
285 // hold() or returns an object that already has its "evaluated"
286 // flag set, such as a symbol or a numeric.
287 const ex & tmpex = other.eval(1);
289 // Eventually, the eval() recursion goes through the "else" branch
290 // below, which assures that the object pointed to by tmpex.bp is
291 // allocated on the heap (either it was already on the heap or it
292 // is a heap-allocated duplicate of another object).
293 GINAC_ASSERT(tmpex.bp->flags & status_flags::dynallocated);
295 // If the original object is not referenced but heap-allocated,
296 // it means that eval() hit case b) above. The original object is
297 // no longer needed (it evaluated into something different), so we
298 // delete it (because nobody else will).
299 if ((other.get_refcount() == 0) && (other.flags & status_flags::dynallocated))
300 delete &other; // yes, you can apply delete to a const pointer
302 // We can't return a basic& here because the tmpex is destroyed as
303 // soon as we leave the function, which would deallocate the
309 // The easy case: making an "ex" out of an evaluated object.
310 if (other.flags & status_flags::dynallocated) {
312 // The object is already heap-allocated, so we can just make
313 // another reference to it.
314 return ptr<basic>(const_cast<basic &>(other));
318 // The object is not heap-allocated, so we create a duplicate
320 basic *bp = other.duplicate();
321 bp->setflag(status_flags::dynallocated);
322 GINAC_ASSERT(bp->get_refcount() == 0);
328 basic & ex::construct_from_int(int i)
330 switch (i) { // prefer flyweights over new objects
332 return *const_cast<numeric *>(_num_12_p);
334 return *const_cast<numeric *>(_num_11_p);
336 return *const_cast<numeric *>(_num_10_p);
338 return *const_cast<numeric *>(_num_9_p);
340 return *const_cast<numeric *>(_num_8_p);
342 return *const_cast<numeric *>(_num_7_p);
344 return *const_cast<numeric *>(_num_6_p);
346 return *const_cast<numeric *>(_num_5_p);
348 return *const_cast<numeric *>(_num_4_p);
350 return *const_cast<numeric *>(_num_3_p);
352 return *const_cast<numeric *>(_num_2_p);
354 return *const_cast<numeric *>(_num_1_p);
356 return *const_cast<numeric *>(_num0_p);
358 return *const_cast<numeric *>(_num1_p);
360 return *const_cast<numeric *>(_num2_p);
362 return *const_cast<numeric *>(_num3_p);
364 return *const_cast<numeric *>(_num4_p);
366 return *const_cast<numeric *>(_num5_p);
368 return *const_cast<numeric *>(_num6_p);
370 return *const_cast<numeric *>(_num7_p);
372 return *const_cast<numeric *>(_num8_p);
374 return *const_cast<numeric *>(_num9_p);
376 return *const_cast<numeric *>(_num10_p);
378 return *const_cast<numeric *>(_num11_p);
380 return *const_cast<numeric *>(_num12_p);
382 basic *bp = new numeric(i);
383 bp->setflag(status_flags::dynallocated);
384 GINAC_ASSERT(bp->get_refcount() == 0);
389 basic & ex::construct_from_uint(unsigned int i)
391 switch (i) { // prefer flyweights over new objects
393 return *const_cast<numeric *>(_num0_p);
395 return *const_cast<numeric *>(_num1_p);
397 return *const_cast<numeric *>(_num2_p);
399 return *const_cast<numeric *>(_num3_p);
401 return *const_cast<numeric *>(_num4_p);
403 return *const_cast<numeric *>(_num5_p);
405 return *const_cast<numeric *>(_num6_p);
407 return *const_cast<numeric *>(_num7_p);
409 return *const_cast<numeric *>(_num8_p);
411 return *const_cast<numeric *>(_num9_p);
413 return *const_cast<numeric *>(_num10_p);
415 return *const_cast<numeric *>(_num11_p);
417 return *const_cast<numeric *>(_num12_p);
419 basic *bp = new numeric(i);
420 bp->setflag(status_flags::dynallocated);
421 GINAC_ASSERT(bp->get_refcount() == 0);
426 basic & ex::construct_from_long(long i)
428 switch (i) { // prefer flyweights over new objects
430 return *const_cast<numeric *>(_num_12_p);
432 return *const_cast<numeric *>(_num_11_p);
434 return *const_cast<numeric *>(_num_10_p);
436 return *const_cast<numeric *>(_num_9_p);
438 return *const_cast<numeric *>(_num_8_p);
440 return *const_cast<numeric *>(_num_7_p);
442 return *const_cast<numeric *>(_num_6_p);
444 return *const_cast<numeric *>(_num_5_p);
446 return *const_cast<numeric *>(_num_4_p);
448 return *const_cast<numeric *>(_num_3_p);
450 return *const_cast<numeric *>(_num_2_p);
452 return *const_cast<numeric *>(_num_1_p);
454 return *const_cast<numeric *>(_num0_p);
456 return *const_cast<numeric *>(_num1_p);
458 return *const_cast<numeric *>(_num2_p);
460 return *const_cast<numeric *>(_num3_p);
462 return *const_cast<numeric *>(_num4_p);
464 return *const_cast<numeric *>(_num5_p);
466 return *const_cast<numeric *>(_num6_p);
468 return *const_cast<numeric *>(_num7_p);
470 return *const_cast<numeric *>(_num8_p);
472 return *const_cast<numeric *>(_num9_p);
474 return *const_cast<numeric *>(_num10_p);
476 return *const_cast<numeric *>(_num11_p);
478 return *const_cast<numeric *>(_num12_p);
480 basic *bp = new numeric(i);
481 bp->setflag(status_flags::dynallocated);
482 GINAC_ASSERT(bp->get_refcount() == 0);
487 basic & ex::construct_from_ulong(unsigned long i)
489 switch (i) { // prefer flyweights over new objects
491 return *const_cast<numeric *>(_num0_p);
493 return *const_cast<numeric *>(_num1_p);
495 return *const_cast<numeric *>(_num2_p);
497 return *const_cast<numeric *>(_num3_p);
499 return *const_cast<numeric *>(_num4_p);
501 return *const_cast<numeric *>(_num5_p);
503 return *const_cast<numeric *>(_num6_p);
505 return *const_cast<numeric *>(_num7_p);
507 return *const_cast<numeric *>(_num8_p);
509 return *const_cast<numeric *>(_num9_p);
511 return *const_cast<numeric *>(_num10_p);
513 return *const_cast<numeric *>(_num11_p);
515 return *const_cast<numeric *>(_num12_p);
517 basic *bp = new numeric(i);
518 bp->setflag(status_flags::dynallocated);
519 GINAC_ASSERT(bp->get_refcount() == 0);
524 basic & ex::construct_from_double(double d)
526 basic *bp = new numeric(d);
527 bp->setflag(status_flags::dynallocated);
528 GINAC_ASSERT(bp->get_refcount() == 0);
532 ptr<basic> ex::construct_from_string_and_lst(const std::string &s, const ex &l)
535 set_lexer_symbols(l);
536 ginac_yyrestart(NULL);
538 throw (std::runtime_error(get_parser_error()));
544 // static member variables
550 // functions which are not member functions