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 6cac523c38625d8bddad69dcbc648d4b629665c4..992b151079c60aee8daaf6a632c4cbff1f5486a3 100644 (file)
--- a/ginac/parser/parser.cpp
+++ b/ginac/parser/parser.cpp
@@ -1,13 +1,72 @@
-#include <stdexcept>
-#include <sstream>
-#include "parser.hpp"
-#include "lexer.hpp"
-#include "debug.hpp"
+/** @file parser.cpp
+ *
+ *  Implementation of GiNaC's parser. */
+
+/*
+ *  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
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "parser.h"
+#include "lexer.h"
+#include "debug.h"
 #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;
+}
 
-namespace GiNaC 
+// 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()
@@ -43,7 +102,9 @@ ex parser::parse_identifier_expr()
                Parse_error_("no function \"" << name << "\" with " <<
                             args.size() << " arguments");
        }
-       ex ret = reader->second(args);
+       // 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;
 }
 
@@ -59,8 +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()
@@ -138,6 +198,13 @@ ex parser::operator()(std::istream& input)
        scanner->switch_input(&input);
        get_next_tok();
        ex ret = parse_expression();
+       // parse_expression() stops if it encounters an unknown token.
+       // This is not a bug: since the parser is recursive checking
+       // whether the next token is valid is responsibility of the caller.
+       // Hence make sure nothing is left in the stream:
+       if (token != lexer::token_type::eof)
+               Parse_error("expected EOF");
+
        return ret;
 }