X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fex.h;h=d16bdbc1998c5b31de414f232b42c8e675baa97a;hp=e9f72bbee36dd501d29e5a86ec5a459368ca8118;hb=757406e244f4f257aafaa0f355d5376122cea10e;hpb=d448856f20cb58f939ddbf636e7f72e3599b1468

diff --git a/ginac/ex.h b/ginac/ex.h
index e9f72bbe..d16bdbc1 100644
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -3,7 +3,7 @@
  *  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
@@ -23,20 +23,34 @@
 #ifndef __GINAC_EX_H__
 #define __GINAC_EX_H__
 
-#include "basic.h"
-#include "operators.h"
-
+#include <iosfwd>
 #include <functional>
 
+#include "basic.h"
+#include "ptr.h"
+
 namespace GiNaC {
 
-// Sorry, this is the only constant to pollute the global scope, the other ones
-// are defined in utils.h and not visible from outside.
-class ex;
-extern const ex & _ex0(void);     ///<  single ex(numeric(0))
 
-class symbol;
-class lst;
+/** Helper class to initialize the library.  There must be one static object
+ *  of this class in every object file that makes use of our flyweights in
+ *  order to guarantee proper initialization.  Hence we put it into this
+ *  file which is included by every relevant file anyways.  This is modeled
+ *  after section 27.4.2.1.6 of the C++ standard, where cout and friends are
+ *  set up.
+ *
+ *  @see utils.cpp */
+class library_init {
+public:
+	library_init();
+	~library_init();
+private:
+	static int count;
+};
+/** For construction of flyweights, etc. */
+static library_init library_initializer;
+
+
 class scalar_products;
 
 
@@ -52,15 +66,15 @@ class ex
 	template<class T> friend bool is_a(const ex &);
 	template<class T> friend bool is_exactly_a(const ex &);
 	
-// member functions
-	
-	// default ctor, dtor, copy ctor assignment operator and helpers
+	// default constructor, copy constructor and assignment operator
 public:
 	ex();
-	~ex();
+#ifdef OBSCURE_CINT_HACK
 	ex(const ex & other);
 	ex & operator=(const ex & other);
-	// other ctors
+#endif
+
+	// other constructors
 public:
 	ex(const basic & other);
 	ex(int i);
@@ -68,89 +82,138 @@ public:
 	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->flags & status_flags::dynallocated);
+		GINAC_ASSERT(other.bp->flags & status_flags::dynallocated);
+		bp.swap(other.bp);
+	}
+
+	// evaluation
+	ex eval(int level = 0) const { return bp->eval(level); }
+	ex evalf(int level = 0) const { return bp->evalf(level); }
+	ex evalm() const { return bp->evalm(); }
+	ex eval_ncmul(const exvector & v) const { return bp->eval_ncmul(v); }
+
+	// printing
 	void print(const print_context & c, unsigned level = 0) const;
-	void printtree(std::ostream & os) const;
-	void dbgprint(void) const;
-	void dbgprinttree(void) const;
+	void dbgprint() const;
+	void dbgprinttree() const;
+
+	// info
 	bool info(unsigned inf) const { return bp->info(inf); }
-	unsigned nops() const { return bp->nops(); }
-	ex expand(unsigned options=0) const;
+
+	// operand access
+	size_t nops() const { return bp->nops(); }
+	ex op(size_t i) const { return bp->op(i); }
+	ex operator[](const ex & index) const { return (*bp)[index]; }
+	ex operator[](size_t i) const { return (*bp)[i]; }
+	ex & let_op(size_t i);
+	ex & operator[](const ex & index);
+	ex & operator[](size_t i);
+	ex lhs() const;
+	ex rhs() const;
+
+	// pattern matching
 	bool has(const ex & pattern) const { return bp->has(pattern); }
+	bool find(const ex & pattern, lst & found) const;
+	bool match(const ex & pattern) const;
+	bool match(const ex & pattern, lst & repl_lst) const { return bp->match(pattern, repl_lst); }
+
+	// substitutions
+	ex subs(const exmap & m, unsigned options = 0) const;
+	ex subs(const lst & ls, const lst & lr, unsigned options = 0) const;
+	ex subs(const ex & e, unsigned options = 0) const;
+
+	// function mapping
 	ex map(map_function & f) const { return bp->map(f); }
 	ex map(ex (*f)(const ex & e)) const;
-	bool find(const ex & pattern, lst & found) const;
+
+	// visitors and tree traversal
+	void accept(visitor & v) const { bp->accept(v); }
+	void traverse_preorder(visitor & v) const;
+	void traverse_postorder(visitor & v) const;
+	void traverse(visitor & v) const { traverse_preorder(v); }
+
+	// degree/coeff
 	int degree(const ex & s) const { return bp->degree(s); }
 	int ldegree(const ex & s) const { return bp->ldegree(s); }
 	ex coeff(const ex & s, int n = 1) const { return bp->coeff(s, n); }
 	ex lcoeff(const ex & s) const { return coeff(s, degree(s)); }
 	ex tcoeff(const ex & s) const { return coeff(s, ldegree(s)); }
-	ex numer(void) const;
-	ex denom(void) const;
-	ex numer_denom(void) const;
+
+	// expand/collect
+	ex expand(unsigned options=0) const;
+	ex collect(const ex & s, bool distributed = false) const { return bp->collect(s, distributed); }
+
+	// differentiation and series expansion
+	ex diff(const symbol & s, unsigned nth = 1) const;
+	ex series(const ex & r, int order, unsigned options = 0) const;
+
+	// rational functions
+	ex normal(int level = 0) const;
+	ex to_rational(lst &repl_lst) const;
+	ex to_polynomial(lst &repl_lst) const;
+	ex numer() const;
+	ex denom() const;
+	ex numer_denom() const;
+
+	// polynomial algorithms
 	ex unit(const symbol &x) const;
 	ex content(const symbol &x) const;
-	numeric integer_content(void) const;
+	numeric integer_content() const;
 	ex primpart(const symbol &x) const;
 	ex primpart(const symbol &x, const ex &cont) const;
-	ex normal(int level = 0) const;
-	ex to_rational(lst &repl_lst) const { return bp->to_rational(repl_lst); }
 	ex smod(const numeric &xi) const { return bp->smod(xi); }
-	numeric max_coefficient(void) const;
-	ex collect(const ex & s, bool distributed = false) const { return bp->collect(s, distributed); }
-	ex eval(int level = 0) const { return bp->eval(level); }
-	ex evalf(int level = 0) const { return bp->evalf(level); }
-	ex evalm(void) const { return bp->evalm(); }
-	ex diff(const symbol & s, unsigned nth = 1) const;
-	ex series(const ex & r, int order, unsigned options = 0) const;
-	bool match(const ex & pattern) const;
-	bool match(const ex & pattern, lst & repl_lst) const { return bp->match(pattern, repl_lst); }
-	ex subs(const lst & ls, const lst & lr, bool no_pattern = false) const { return bp->subs(ls, lr, no_pattern); }
-	ex subs(const ex & e, bool no_pattern = false) const { return bp->subs(e, no_pattern); }
-	exvector get_free_indices(void) const { return bp->get_free_indices(); }
-	ex simplify_indexed(void) const;
+	numeric max_coefficient() const;
+
+	// indexed objects
+	exvector get_free_indices() const { return bp->get_free_indices(); }
+	ex simplify_indexed() const;
 	ex simplify_indexed(const scalar_products & sp) const;
-	ex symmetrize(void) const;
-	ex symmetrize(const lst & l) const;
-	ex antisymmetrize(void) const;
-	ex antisymmetrize(const lst & l) const;
-	ex symmetrize_cyclic(void) const;
-	ex symmetrize_cyclic(const lst & l) const;
-	ex simplify_ncmul(const exvector & v) const { return bp->simplify_ncmul(v); }
-	ex operator[](const ex & index) const;
-	ex operator[](int i) const;
-	ex op(int i) const { return bp->op(i); }
-	ex & let_op(int i);
-	ex lhs(void) const;
-	ex rhs(void) const;
+
+	// comparison
 	int compare(const ex & other) const;
 	bool is_equal(const ex & other) const;
-	bool is_zero(void) const { return is_equal(_ex0()); }
+	bool is_zero() const { extern const ex _ex0; return is_equal(_ex0); }
 	
-	unsigned return_type(void) const { return bp->return_type(); }
-	unsigned return_type_tinfo(void) const { return bp->return_type_tinfo(); }
-	unsigned gethash(void) const { return bp->gethash(); }
+	// symmetry
+	ex symmetrize() const;
+	ex symmetrize(const lst & l) const;
+	ex antisymmetrize() const;
+	ex antisymmetrize(const lst & l) const;
+	ex symmetrize_cyclic() const;
+	ex symmetrize_cyclic(const lst & l) const;
+
+	// noncommutativity
+	unsigned return_type() const { return bp->return_type(); }
+	unsigned return_type_tinfo() const { return bp->return_type_tinfo(); }
+
+	unsigned gethash() const { return bp->gethash(); }
+
 private:
-	void construct_from_basic(const basic & other);
-	void construct_from_int(int i);
-	void construct_from_uint(unsigned int i);
-	void construct_from_long(long i);
-	void construct_from_ulong(unsigned long i);
-	void construct_from_double(double d);
-	void construct_from_string_and_lst(const std::string &s, const ex &l);
+	static ptr<basic> construct_from_basic(const basic & other);
+	static basic & construct_from_int(int i);
+	static basic & construct_from_uint(unsigned int i);
+	static basic & construct_from_long(long i);
+	static basic & construct_from_ulong(unsigned long i);
+	static basic & construct_from_double(double d);
+	static ptr<basic> construct_from_string_and_lst(const std::string &s, const ex &l);
 	void makewriteable();
 
 #ifdef OBSCURE_CINT_HACK
 public:
-	static bool last_created_or_assigned_bp_can_be_converted_to_ex(void)
+	static bool last_created_or_assigned_bp_can_be_converted_to_ex()
 	{
 		if (last_created_or_assigned_bp==0) return false;
 		if ((last_created_or_assigned_bp->flags &
@@ -160,25 +223,21 @@ public:
 		return true;
 	}
 protected:
-	void update_last_created_or_assigned_bp(void)
+	void update_last_created_or_assigned_bp()
 	{
-		if (last_created_or_assigned_bp!=0) {
-			if (--last_created_or_assigned_bp->refcount == 0) {
-				delete last_created_or_assigned_bp;
-			}
-		}
 		last_created_or_assigned_bp = bp;
-		++last_created_or_assigned_bp->refcount;
 		last_created_or_assigned_exp = (long)(void *)(this);
 	}
 #endif // def OBSCURE_CINT_HACK
 
 // member variables
 
-public:
-	basic *bp;      ///< pointer to basic object managed by this, direct manipulation deprecated
+private:
+	ptr<basic> bp;      ///< pointer to basic object managed by this
+
 #ifdef OBSCURE_CINT_HACK
-	static basic * last_created_or_assigned_bp;
+public:
+	static ptr<basic> last_created_or_assigned_bp;
 	static basic * dummy_bp;
 	static long last_created_or_assigned_exp;
 #endif // def OBSCURE_CINT_HACK
@@ -187,125 +246,96 @@ public:
 
 // performance-critical inlined method implementations
 
+// This needs to be a basic* because we don't know that numeric is derived
+// from basic and we need a basic& for the ex default constructor
+extern const basic *_num0_bp;
+
 inline
-ex::ex() : bp(_ex0().bp)
+ex::ex() : bp(*const_cast<basic *>(_num0_bp))
 {
-	/*debugmsg("ex default ctor",LOGLEVEL_CONSTRUCT);*/
-	GINAC_ASSERT(_ex0().bp!=0);
-	GINAC_ASSERT(_ex0().bp->flags & status_flags::dynallocated);
-	GINAC_ASSERT(bp!=0);
-	++bp->refcount;
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
-inline
-ex::~ex()
-{
-	/*debugmsg("ex dtor",LOGLEVEL_DESTRUCT);*/
-	GINAC_ASSERT(bp!=0);
-	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
-	if (--bp->refcount == 0)
-		delete bp;
-}
-
+#ifdef OBSCURE_CINT_HACK
 inline
 ex::ex(const ex & other) : bp(other.bp)
 {
-	/*debugmsg("ex copy ctor",LOGLEVEL_CONSTRUCT);*/
-	GINAC_ASSERT(bp!=0);
 	GINAC_ASSERT((bp->flags) & status_flags::dynallocated);
-	++bp->refcount;
-#ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
-#endif // def OBSCURE_CINT_HACK
 }
 
 inline
 ex & ex::operator=(const ex & other)
 {
-	/*debugmsg("ex operator=",LOGLEVEL_ASSIGNMENT);*/
-	GINAC_ASSERT(bp!=0);
 	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
-	GINAC_ASSERT(other.bp!=0);
 	GINAC_ASSERT(other.bp->flags & status_flags::dynallocated);
-	// NB: must first increment other.bp->refcount, since other might be *this.
-	++other.bp->refcount;
-	if (--bp->refcount==0)
-		delete bp;
 	bp = other.bp;
-#ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
-#endif // def OBSCURE_CINT_HACK
 	return *this;
 }
+#endif // def OBSCURE_CINT_HACK
 
 inline
-ex::ex(const basic & other)
+ex::ex(const basic & other) : bp(construct_from_basic(other))
 {
-	/*debugmsg("ex ctor from basic",LOGLEVEL_CONSTRUCT);*/
-	construct_from_basic(other);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
 inline
-ex::ex(int i)
+ex::ex(int i) : bp(construct_from_int(i))
 {
-	/*debugmsg("ex ctor from int",LOGLEVEL_CONSTRUCT);*/
-	construct_from_int(i);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
 inline
-ex::ex(unsigned int i)
+ex::ex(unsigned int i) : bp(construct_from_uint(i))
 {
-	/*debugmsg("ex ctor from unsigned int",LOGLEVEL_CONSTRUCT);*/
-	construct_from_uint(i);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
 inline
-ex::ex(long i)
+ex::ex(long i) : bp(construct_from_long(i))
 {
-	/*debugmsg("ex ctor from long",LOGLEVEL_CONSTRUCT);*/
-	construct_from_long(i);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
 inline
-ex::ex(unsigned long i)
+ex::ex(unsigned long i) : bp(construct_from_ulong(i))
 {
-	/*debugmsg("ex ctor from unsigned long",LOGLEVEL_CONSTRUCT);*/
-	construct_from_ulong(i);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
 inline
-ex::ex(double const d)
+ex::ex(double const d) : bp(construct_from_double(d))
 {
-	/*debugmsg("ex ctor from double",LOGLEVEL_CONSTRUCT);*/
-	construct_from_double(d);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
 }
 
 inline
-ex::ex(const std::string &s, const ex &l)
+ex::ex(const std::string &s, const ex &l) : bp(construct_from_string_and_lst(s, l))
 {
-	/*debugmsg("ex ctor from string,lst",LOGLEVEL_CONSTRUCT);*/
-	construct_from_string_and_lst(s, l);
+	GINAC_ASSERT(bp->flags & status_flags::dynallocated);
 #ifdef OBSCURE_CINT_HACK
 	update_last_created_or_assigned_bp();
 #endif // def OBSCURE_CINT_HACK
@@ -314,9 +344,7 @@ ex::ex(const std::string &s, const ex &l)
 inline
 int ex::compare(const ex & other) const
 {
-	GINAC_ASSERT(bp!=0);
-	GINAC_ASSERT(other.bp!=0);
-	if (bp==other.bp)  // trivial case: both expressions point to same basic
+	if (bp == other.bp)  // trivial case: both expressions point to same basic
 		return 0;
 	return bp->compare(*other.bp);
 }
@@ -324,22 +352,25 @@ int ex::compare(const ex & other) const
 inline
 bool ex::is_equal(const ex & other) const
 {
-	GINAC_ASSERT(bp!=0);
-	GINAC_ASSERT(other.bp!=0);
-	if (bp==other.bp)  // trivial case: both expressions point to same basic
+	if (bp == other.bp)  // trivial case: both expressions point to same basic
 		return true;
 	return bp->is_equal(*other.bp);
 }
 
 
 // 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;
 }
 
 // wrapper functions around member functions
-inline unsigned nops(const ex & thisex)
+inline size_t nops(const ex & thisex)
 { return thisex.nops(); }
 
 inline ex expand(const ex & thisex, unsigned options = 0)
@@ -375,6 +406,9 @@ inline ex normal(const ex & thisex, int level=0)
 inline ex to_rational(const ex & thisex, lst & repl_lst)
 { return thisex.to_rational(repl_lst); }
 
+inline ex to_polynomial(const ex & thisex, lst & repl_lst)
+{ return thisex.to_polynomial(repl_lst); }
+
 inline ex collect(const ex & thisex, const ex & s, bool distributed = false)
 { return thisex.collect(s, distributed); }
 
@@ -396,12 +430,6 @@ inline ex series(const ex & thisex, const ex & r, int order, unsigned options =
 inline bool match(const ex & thisex, const ex & pattern, lst & repl_lst)
 { return thisex.match(pattern, repl_lst); }
 
-inline ex subs(const ex & thisex, const ex & e)
-{ return thisex.subs(e); }
-
-inline ex subs(const ex & thisex, const lst & ls, const lst & lr)
-{ return thisex.subs(ls, lr); }
-
 inline ex simplify_indexed(const ex & thisex)
 { return thisex.simplify_indexed(); }
 
@@ -426,7 +454,7 @@ inline ex symmetrize_cyclic(const ex & thisex)
 inline ex symmetrize_cyclic(const ex & thisex, const lst & l)
 { return thisex.symmetrize_cyclic(l); }
 
-inline ex op(const ex & thisex, int i)
+inline ex op(const ex & thisex, size_t i)
 { return thisex.op(i); }
 
 inline ex lhs(const ex & thisex)
@@ -442,6 +470,11 @@ 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.compare(rh) < 0; }
@@ -451,17 +484,35 @@ struct ex_is_equal : 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); }
 };
 
+inline ex ex::subs(const exmap & m, unsigned options) const
+{
+	return bp->subs(m, options);
+}
+
+inline ex subs(const ex & thisex, const exmap & m, unsigned options = 0)
+{ return thisex.subs(m, options); }
+
+inline ex subs(const ex & thisex, const lst & ls, const lst & lr, unsigned options = 0)
+{ return thisex.subs(ls, lr, options); }
+
+inline ex subs(const ex & thisex, const ex & e, unsigned options = 0)
+{ return thisex.subs(e, options); }
+
 
 /* Convert function pointer to function object suitable for map(). */
 class pointer_to_map_function : public map_function {
 protected:
 	ex (*ptr)(const ex &);
 public:
-	explicit pointer_to_map_function(ex (*x)(const ex &)) : ptr(x) {}
+	explicit pointer_to_map_function(ex x(const ex &)) : ptr(x) {}
 	ex operator()(const ex & e) { return ptr(e); }
 };
 
@@ -471,7 +522,7 @@ protected:
 	ex (*ptr)(const ex &, T1);
 	T1 arg1;
 public:
-	explicit pointer_to_map_function_1arg(ex (*x)(const ex &, T1), T1 a1) : ptr(x), arg1(a1) {}
+	explicit pointer_to_map_function_1arg(ex x(const ex &, T1), T1 a1) : ptr(x), arg1(a1) {}
 	ex operator()(const ex & e) { return ptr(e, arg1); }
 };
 
@@ -482,7 +533,7 @@ protected:
 	T1 arg1;
 	T2 arg2;
 public:
-	explicit pointer_to_map_function_2args(ex (*x)(const ex &, T1, T2), T1 a1, T2 a2) : ptr(x), arg1(a1), arg2(a2) {}
+	explicit pointer_to_map_function_2args(ex x(const ex &, T1, T2), T1 a1, T2 a2) : ptr(x), arg1(a1), arg2(a2) {}
 	ex operator()(const ex & e) { return ptr(e, arg1, arg2); }
 };
 
@@ -494,16 +545,46 @@ protected:
 	T2 arg2;
 	T3 arg3;
 public:
-	explicit pointer_to_map_function_3args(ex (*x)(const ex &, T1, T2, T3), T1 a1, T2 a2, T3 a3) : ptr(x), arg1(a1), arg2(a2), arg3(a3) {}
+	explicit pointer_to_map_function_3args(ex x(const ex &, T1, T2, T3), T1 a1, T2 a2, T3 a3) : ptr(x), arg1(a1), arg2(a2), arg3(a3) {}
 	ex operator()(const ex & e) { return ptr(e, arg1, arg2, arg3); }
 };
 
-inline ex ex::map(ex (*f)(const ex & e)) const
+inline ex ex::map(ex f(const ex &)) const
 {
 	pointer_to_map_function fcn(f);
 	return bp->map(fcn);
 }
 
+// convenience type checker template functions
+
+/** Check if ex is a handle to a T, including base classes. */
+template <class T>
+inline bool is_a(const ex &obj)
+{
+	return is_a<T>(*obj.bp);
+}
+
+/** Check if ex is a handle to a T, not including base classes. */
+template <class T>
+inline bool is_exactly_a(const ex &obj)
+{
+	return is_exactly_a<T>(*obj.bp);
+}
+
+/** Return a reference to the basic-derived class T object embedded in an
+ *  expression.  This is fast but unsafe: the result is undefined if the
+ *  expression does not contain a T object at its top level.  Hence, you
+ *  should generally check the type of e first.
+ *
+ *  @param e expression
+ *  @return reference to object of class T
+ *  @see is_exactly_a<class T>() */
+template <class T>
+inline const T &ex_to(const ex &e)
+{
+	GINAC_ASSERT(is_a<T>(e));
+	return static_cast<const T &>(*e.bp);
+}
 
 } // namespace GiNaC