#include <iosfwd>
#include <iterator>
#include <functional>
+#include <stack>
#include "basic.h"
#include "ptr.h"
class scalar_products;
+class const_iterator;
/** Lightweight wrapper for GiNaC's symbolic objects. Basically all it does is
ex(const std::string &s, const ex &l);
public:
- // Iterators
- class const_iterator : public std::iterator<std::random_access_iterator_tag, ex, ptrdiff_t, const ex *, const ex &>
- {
- friend class ex;
-
- public:
- const_iterator() throw() {}
- const_iterator(const basic *bp_, size_t i_) throw() : bp(bp_), i(i_) {}
-
- bool operator==(const const_iterator &other) const throw()
- {
- return bp == other.bp && i == other.i;
- }
-
- bool operator!=(const const_iterator &other) const throw()
- {
- return !(*this == other);
- }
-
- bool operator<(const const_iterator &other) const throw()
- {
- return i < other.i;
- }
-
- bool operator>(const const_iterator &other) const throw()
- {
- return other < *this;
- }
-
- bool operator<=(const const_iterator &other) const throw()
- {
- return !(other < *this);
- }
-
- bool operator>=(const const_iterator &other) const throw()
- {
- return !(*this < other);
- }
-
- // This should return an ex&, but that would be a reference to a
- // temporary value
- ex operator*() const
- {
- return bp->op(i);
- }
-
-#if 0
- // How do we make this work in the context of the "reference to
- // temporary" problem? Return an auto_ptr?
- pointer operator->() const
- {
- return &(operator*());
- }
-#endif
-
- const_iterator &operator++() throw()
- {
- ++i;
- return *this;
- }
-
- const_iterator operator++(int) throw()
- {
- const_iterator tmp = *this;
- ++i;
- return tmp;
- }
-
- const_iterator &operator+=(difference_type n) throw()
- {
- i += n;
- return *this;
- }
-
- const_iterator operator+(difference_type n) const throw()
- {
- return const_iterator(bp, i + n);
- }
-
- inline friend const_iterator operator+(difference_type n, const const_iterator &it) throw()
- {
- return const_iterator(it.bp, it.i + n);
- }
-
- const_iterator &operator--() throw()
- {
- --i;
- return *this;
- }
-
- const_iterator operator--(int) throw()
- {
- const_iterator tmp = *this;
- --i;
- return tmp;
- }
-
- const_iterator &operator-=(difference_type n) throw()
- {
- i -= n;
- return *this;
- }
-
- const_iterator operator-(difference_type n) const throw()
- {
- return const_iterator(bp, i - n);
- }
-
- inline friend difference_type operator-(const const_iterator &lhs, const const_iterator &rhs) throw()
- {
- return lhs.i - rhs.i;
- }
-
- ex operator[](difference_type n) const
- {
- return bp->op(i + n);
- }
-
- protected:
- const basic *bp;
- size_t i;
- };
-
- const_iterator begin() const throw() { return const_iterator(get_pointer(bp), 0); }
- const_iterator end() const throw() { return const_iterator(get_pointer(bp), bp->nops()); }
-
-#if 0
- // This doesn't work because of the "reference to temporary" problem
- // in operator*()
- typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
- const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
- const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
-#endif
-
// non-virtual functions in this class
public:
/** Efficiently swap the contents of two expressions. */
bp.swap(other.bp);
}
+ // iterators
+ const_iterator begin() const throw();
+ const_iterator end() const throw();
+
// evaluation
ex eval(int level = 0) const { return bp->eval(level); }
ex evalf(int level = 0) const { return bp->evalf(level); }
}
+// Iterators
+
+class const_iterator : public std::iterator<std::random_access_iterator_tag, ex, ptrdiff_t, const ex *, const ex &>
+{
+ friend class ex;
+ friend class const_preorder_iterator;
+ friend class const_postorder_iterator;
+
+public:
+ const_iterator() throw() {}
+
+private:
+ const_iterator(const ex &e_, size_t i_) throw() : e(e_), i(i_) {}
+
+public:
+ // This should return an ex&, but that would be a reference to a
+ // temporary value
+ ex operator*() const
+ {
+ return e.op(i);
+ }
+
+#if 0
+ // How do we make this work in the context of the "reference to
+ // temporary" problem? Return an auto_ptr?
+ pointer operator->() const
+ {
+ return &(operator*());
+ }
+#endif
+
+ ex operator[](difference_type n) const
+ {
+ return e.op(i + n);
+ }
+
+ const_iterator &operator++() throw()
+ {
+ ++i;
+ return *this;
+ }
+
+ const_iterator operator++(int) throw()
+ {
+ const_iterator tmp = *this;
+ ++i;
+ return tmp;
+ }
+
+ const_iterator &operator+=(difference_type n) throw()
+ {
+ i += n;
+ return *this;
+ }
+
+ const_iterator operator+(difference_type n) const throw()
+ {
+ return const_iterator(e, i + n);
+ }
+
+ inline friend const_iterator operator+(difference_type n, const const_iterator &it) throw()
+ {
+ return const_iterator(it.e, it.i + n);
+ }
+
+ const_iterator &operator--() throw()
+ {
+ --i;
+ return *this;
+ }
+
+ const_iterator operator--(int) throw()
+ {
+ const_iterator tmp = *this;
+ --i;
+ return tmp;
+ }
+
+ const_iterator &operator-=(difference_type n) throw()
+ {
+ i -= n;
+ return *this;
+ }
+
+ const_iterator operator-(difference_type n) const throw()
+ {
+ return const_iterator(e, i - n);
+ }
+
+ inline friend difference_type operator-(const const_iterator &lhs, const const_iterator &rhs) throw()
+ {
+ return lhs.i - rhs.i;
+ }
+
+ bool operator==(const const_iterator &other) const throw()
+ {
+ return are_ex_trivially_equal(e, other.e) && i == other.i;
+ }
+
+ bool operator!=(const const_iterator &other) const throw()
+ {
+ return !(*this == other);
+ }
+
+ bool operator<(const const_iterator &other) const throw()
+ {
+ return i < other.i;
+ }
+
+ bool operator>(const const_iterator &other) const throw()
+ {
+ return other < *this;
+ }
+
+ bool operator<=(const const_iterator &other) const throw()
+ {
+ return !(other < *this);
+ }
+
+ bool operator>=(const const_iterator &other) const throw()
+ {
+ return !(*this < other);
+ }
+
+protected:
+ ex e; // this used to be a "const basic *", but in view of object fusion that wouldn't be safe
+ size_t i;
+};
+
+namespace internal {
+
+struct _iter_rep {
+ _iter_rep(const ex &e_, size_t i_, size_t i_end_) : e(e_), i(i_), i_end(i_end_) {}
+
+ bool operator==(const _iter_rep &other) const throw()
+ {
+ return are_ex_trivially_equal(e, other.e) && i == other.i;
+ }
+
+ bool operator!=(const _iter_rep &other) const throw()
+ {
+ return !(*this == other);
+ }
+
+ ex e;
+ size_t i;
+ size_t i_end;
+};
+
+} // namespace internal
+
+class const_preorder_iterator : public std::iterator<std::forward_iterator_tag, ex, ptrdiff_t, const ex *, const ex &>
+{
+public:
+ const_preorder_iterator() throw() {}
+
+ // Provide implicit conversion from const_iterator, so begin() and
+ // end() can be used to create const_preorder_iterators
+ const_preorder_iterator(const const_iterator & cit)
+ {
+ s.push(internal::_iter_rep(cit.e, cit.i, cit.e.nops()));
+ }
+
+public:
+ ex operator*() const
+ {
+ const internal::_iter_rep & r = s.top();
+ return r.e.op(r.i);
+ }
+
+ // operator->() not implemented (see above)
+
+ const_preorder_iterator &operator++()
+ {
+ increment();
+ return *this;
+ }
+
+ const_preorder_iterator operator++(int)
+ {
+ const_preorder_iterator tmp = *this;
+ increment();
+ return tmp;
+ }
+
+ bool operator==(const const_preorder_iterator &other) const throw()
+ {
+ return s == other.s;
+ }
+
+ bool operator!=(const const_preorder_iterator &other) const throw()
+ {
+ return !(*this == other);
+ }
+
+private:
+ std::stack<internal::_iter_rep> s;
+
+ void increment()
+ {
+ internal::_iter_rep & current = s.top();
+ const ex & child = current.e.op(current.i);
+ size_t n = child.nops();
+ if (n)
+ s.push(internal::_iter_rep(child, 0, n));
+ else
+ ++current.i;
+
+ while (s.top().i == s.top().i_end && s.size() > 1) {
+ s.pop();
+ ++s.top().i;
+ }
+ }
+};
+
+class const_postorder_iterator : public std::iterator<std::forward_iterator_tag, ex, ptrdiff_t, const ex *, const ex &>
+{
+public:
+ const_postorder_iterator() throw() {}
+
+ // Provide implicit conversion from const_iterator, so begin() and
+ // end() can be used to create const_postorder_iterators
+ const_postorder_iterator(const const_iterator & cit)
+ {
+ s.push(internal::_iter_rep(cit.e, cit.i, cit.e.nops()));
+ descend();
+ }
+
+public:
+ ex operator*() const
+ {
+ const internal::_iter_rep & r = s.top();
+ return r.e.op(r.i);
+ }
+
+ // operator->() not implemented
+
+ const_postorder_iterator &operator++()
+ {
+ increment();
+ return *this;
+ }
+
+ const_postorder_iterator operator++(int)
+ {
+ const_postorder_iterator tmp = *this;
+ increment();
+ return tmp;
+ }
+
+ bool operator==(const const_postorder_iterator &other) const throw()
+ {
+ return s == other.s;
+ }
+
+ bool operator!=(const const_postorder_iterator &other) const throw()
+ {
+ return !(*this == other);
+ }
+
+private:
+ std::stack<internal::_iter_rep> s;
+
+ void descend()
+ {
+ while (s.top().i != s.top().i_end && s.top().e.op(s.top().i).nops() > 0) {
+ const internal::_iter_rep & current = s.top();
+ const ex & child = current.e.op(current.i);
+ s.push(internal::_iter_rep(child, 0, child.nops()));
+ }
+ }
+
+ void increment()
+ {
+ ++s.top().i;
+ descend();
+ if (s.top().i == s.top().i_end && s.size() > 1)
+ s.pop();
+ }
+};
+
+inline const_iterator ex::begin() const throw()
+{
+ return const_iterator(*this, 0);
+}
+
+inline const_iterator ex::end() const throw()
+{
+ return const_iterator(*this, nops());
+}
+
+
// utility functions
/** Compare two objects of class quickly without doing a deep tree traversal.
git://www.ginac.de / ginac.git / blobdiff