Parser: don't bother to generate 3 (C++) functions with autogen.

[ginac.git] / ginac / parser / parser.cpp

diff --git a/ginac/parser/parser.cpp b/ginac/parser/parser.cpp
index 52f7e1df3454c9df01b5dc9f90511d4373260397..992b151079c60aee8daaf6a632c4cbff1f5486a3 100644 (file)
--- a/ginac/parser/parser.cpp
+++ b/ginac/parser/parser.cpp
@@ -3,7 +3,7 @@
  *  Implementation of GiNaC's parser. */
 
 /*
- *  GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2011 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
@@ -26,12 +26,48 @@
 #include "mul.h"
 #include "constant.h"
 #include "function.h"
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
+#ifdef HAVE_STDINT_H
+#include <stdint.h> // for uintptr_t
+#endif
 #include <sstream>
 #include <stdexcept>
 
 namespace GiNaC {
 
+// <KLUDGE>
+// Find out if ptr is a pointer to a function or a specially crafted integer.
+// It's possible to distinguish between these because functions are aligned.
+// Returns true if ptr is a pointer and false otherwise.
+static bool decode_serial(unsigned& serial, const reader_func ptr)
+{
+       uintptr_t u = (uintptr_t)(void *)ptr;
+       if (u & 1) {
+               u >>= 1;
+               serial = (unsigned)u;
+               return false;
+       }
+       return true;
+}
+
+// Figures out if ptr is a pointer to function or a serial of GiNaC function.
+// In the former case calls that function, in the latter case constructs
+// GiNaC function with corresponding serial and arguments.
+static ex dispatch_reader_fcn(const reader_func ptr, const exvector& args)
+{
+       unsigned serial = 0; // dear gcc, could you please shut up?
+       bool is_ptr = decode_serial(serial, ptr);
+       if (is_ptr)
+               return ptr(args);
+       else
+               return function(serial, args);
+}
+// </KLUDGE>
+
+
 /// identifier_expr:  identifier |  identifier '(' expression* ')'
 ex parser::parse_identifier_expr()
 {
@@ -66,18 +102,10 @@ ex parser::parse_identifier_expr()
                Parse_error_("no function \"" << name << "\" with " <<
                             args.size() << " arguments");
        }
-       // dirty hack to distinguish between serial numbers of functions and real
-       // pointers.
-       GiNaC::function* f = NULL;
-       try {
-               f = new GiNaC::function(reinterpret_cast<unsigned>(reader->second), args);
-       }
-       catch ( std::runtime_error ) {
-               if ( f ) delete f;
-               ex ret = reader->second(args);
-               return ret;
-       }
-       return f->setflag(status_flags::dynallocated);
+       // reader->second might be a pointer to a C++ function or a specially
+       // crafted serial of a GiNaC::function.
+       ex ret = dispatch_reader_fcn(reader->second, args);
+       return ret;
 }
 
 /// paren_expr:  '(' expression ')'
@@ -92,8 +120,7 @@ ex parser::parse_paren_expr()
        return e;
 }
 
-extern numeric* _num_1_p;
-extern ex _ex0;
+extern const ex _ex0;
 
 /// unary_expr: [+-] expression
 ex parser::parse_unary_expr()