* Interface to GiNaC's light-weight expression handles. */
/*
- * GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
+ * GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
ex(long i);
ex(unsigned long i);
ex(double const d);
+
/** Construct ex from string and a list of symbols. The input grammar is
- * similar to the GiNaC output format. All symbols to be used in the
- * expression must be specified in a lst in the second argument. Undefined
- * symbols and other parser errors will throw an exception. */
+ * similar to the GiNaC output format. All symbols and indices to be used
+ * in the expression must be specified in a lst in the second argument.
+ * Undefined symbols and other parser errors will throw an exception. */
ex(const std::string &s, const ex &l);
// non-virtual functions in this class
public:
- void swap(ex & other);
+ /** Efficiently swap the contents of two expressions. */
+ void swap(ex & other)
+ {
+ GINAC_ASSERT(bp!=0);
+ GINAC_ASSERT(bp->flags & status_flags::dynallocated);
+ GINAC_ASSERT(other.bp!=0);
+ GINAC_ASSERT(other.bp->flags & status_flags::dynallocated);
+
+ basic * tmpbp = bp;
+ bp = other.bp;
+ other.bp = tmpbp;
+ }
+
void print(const print_context & c, unsigned level = 0) const;
void printtree(std::ostream & os) const;
void dbgprint(void) const;
// utility functions
+
+/** Compare two objects of class quickly without doing a deep tree traversal.
+ * @return "true" if they are equal
+ * "false" if equality cannot be established quickly (e1 and e2 may
+ * still be equal, in this case. */
inline bool are_ex_trivially_equal(const ex &e1, const ex &e2)
{
return e1.bp == e2.bp;
inline void swap(ex & e1, ex & e2)
{ e1.swap(e2); }
+// This makes STL algorithms use the more efficient swap operation for ex objects
+inline void iter_swap(std::vector<ex>::iterator i1, std::vector<ex>::iterator i2)
+{ i1->swap(*i2); }
+
/* Function objects for STL sort() etc. */
struct ex_is_less : public std::binary_function<ex, ex, bool> {
bool operator() (const ex &lh, const ex &rh) const { return lh.is_equal(rh); }
};
+struct op0_is_equal : public std::binary_function<ex, ex, bool> {
+ bool operator() (const ex &lh, const ex &rh) const { return lh.op(0).is_equal(rh.op(0)); }
+};
+
struct ex_swap : public std::binary_function<ex, ex, void> {
void operator() (ex &lh, ex &rh) const { lh.swap(rh); }
};