* Added some long-pending docu.

[ginac.git] / ginac / ex.h

diff --git a/ginac/ex.h b/ginac/ex.h
index e9f72bbee36dd501d29e5a86ec5a459368ca8118..e819d13f10544eb8f34e44bf370c3b2995299399 100644 (file)
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -23,17 +23,38 @@
 #ifndef __GINAC_EX_H__
 #define __GINAC_EX_H__
 
+#include <iosfwd>
+#include <functional>
+
 #include "basic.h"
 #include "operators.h"
 
-#include <functional>
-
 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))
+/** 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;
+
+// Current versions of Cint don't link data declared extern within functions.
+// FIXME: Fix Cint and later remove this from here.
+#if defined(G__CINTVERSION)
+extern const class numeric *_num0_p;
+#endif
+
 
 class symbol;
 class lst;
@@ -54,7 +75,7 @@ class ex
        
 // member functions
        
-       // default ctor, dtor, copy ctor assignment operator and helpers
+       // default ctor, dtor, copy ctor, assignment operator and helpers
 public:
        ex();
        ~ex();
@@ -133,7 +154,7 @@ public:
        ex rhs(void) const;
        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(void) 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(); }
@@ -188,12 +209,12 @@ public:
 // performance-critical inlined method implementations
 
 inline
-ex::ex() : bp(_ex0().bp)
+ex::ex()
 {
-       /*debugmsg("ex default ctor",LOGLEVEL_CONSTRUCT);*/
-       GINAC_ASSERT(_ex0().bp!=0);
-       GINAC_ASSERT(_ex0().bp->flags & status_flags::dynallocated);
+       extern const class numeric *_num0_p;
+       bp = (basic*)_num0_p;
        GINAC_ASSERT(bp!=0);
+       GINAC_ASSERT(bp->flags & status_flags::dynallocated);
        ++bp->refcount;
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -203,7 +224,6 @@ ex::ex() : bp(_ex0().bp)
 inline
 ex::~ex()
 {
-       /*debugmsg("ex dtor",LOGLEVEL_DESTRUCT);*/
        GINAC_ASSERT(bp!=0);
        GINAC_ASSERT(bp->flags & status_flags::dynallocated);
        if (--bp->refcount == 0)
@@ -213,7 +233,6 @@ ex::~ex()
 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;
@@ -225,7 +244,6 @@ ex::ex(const ex & other) : bp(other.bp)
 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);
@@ -244,7 +262,6 @@ ex & ex::operator=(const ex & other)
 inline
 ex::ex(const basic & other)
 {
-       /*debugmsg("ex ctor from basic",LOGLEVEL_CONSTRUCT);*/
        construct_from_basic(other);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -254,7 +271,6 @@ ex::ex(const basic & other)
 inline
 ex::ex(int i)
 {
-       /*debugmsg("ex ctor from int",LOGLEVEL_CONSTRUCT);*/
        construct_from_int(i);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -264,7 +280,6 @@ ex::ex(int i)
 inline
 ex::ex(unsigned int i)
 {
-       /*debugmsg("ex ctor from unsigned int",LOGLEVEL_CONSTRUCT);*/
        construct_from_uint(i);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -274,7 +289,6 @@ ex::ex(unsigned int i)
 inline
 ex::ex(long i)
 {
-       /*debugmsg("ex ctor from long",LOGLEVEL_CONSTRUCT);*/
        construct_from_long(i);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -284,7 +298,6 @@ ex::ex(long i)
 inline
 ex::ex(unsigned long i)
 {
-       /*debugmsg("ex ctor from unsigned long",LOGLEVEL_CONSTRUCT);*/
        construct_from_ulong(i);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -294,7 +307,6 @@ ex::ex(unsigned long i)
 inline
 ex::ex(double const d)
 {
-       /*debugmsg("ex ctor from double",LOGLEVEL_CONSTRUCT);*/
        construct_from_double(d);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -304,7 +316,6 @@ ex::ex(double const d)
 inline
 ex::ex(const std::string &s, const ex &l)
 {
-       /*debugmsg("ex ctor from string,lst",LOGLEVEL_CONSTRUCT);*/
        construct_from_string_and_lst(s, l);
 #ifdef OBSCURE_CINT_HACK
        update_last_created_or_assigned_bp();
@@ -333,6 +344,11 @@ bool ex::is_equal(const ex & other) 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;