X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fparser%2Fparse_context.h;h=60151fd37988af0538f6b000bd50285930ee8d7d;hp=07496d7e8e26f0ac13fe0484f42643a2118b0ccd;hb=9a4f392521083d28e1c238e7898ab1d2ac5b73cd;hpb=df823d53c56c762072f534c9f24479090162e33a

diff --git a/ginac/parser/parse_context.h b/ginac/parser/parse_context.h
index 07496d7e..60151fd3 100644
--- a/ginac/parser/parse_context.h
+++ b/ginac/parser/parse_context.h
@@ -3,7 +3,7 @@
  *  Interface to parser context. */
 
 /*
- *  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
@@ -72,18 +72,49 @@ typedef ex (*reader_func)(const exvector& args);
  * foo(x+y, z^2, t)), it looks up such a table to find out which
  * function (or class) corresponds to the given name and has the given
  * number of the arguments.
+ *
+ * N.B.
+ *
+ * 1. The function don't have to return a (GiNaC) function or class, it
+ *    can return any expression.
+ * 2. Overloaded functions/ctors are paritally supported, i.e. there might
+ *    be several functions with the same name, but they should take different
+ *    number of arguments.
+ * 3. User can extend the parser via custom prototype tables. It's possible
+ *    to read user defined classes, create abbreviations, etc.
+ *
+ * NOTE: due to a hack that allows user defined functions to be parsed, the map
+ *       value of type reader_func is internally treated as an unsigned and not as a
+ *       function pointer!! The unsigned has to correspond to the serial number of
+ *       the defined GiNaC function.
  */
-typedef std::map<prototype, unsigned> prototype_table;
+class PrototypeLess
+{
+public:
+	bool operator()(const prototype& p1, const prototype& p2) const
+	{
+		int s = p1.first.compare(p2.first);
+		if (s == 0) {
+			if ((p1.second == 0) || (p2.second == 0)) return false;
+			return p1.second < p2.second;
+		}
+		return s < 0;
+	}
+};
+typedef std::map<prototype, reader_func, PrototypeLess> prototype_table;
 
 /**
- * Creates a default prototype table containing all defined GiNaC functions.
+ * Default prototype table.
+ *
+ * It supports all defined GiNaC functions and "pow", "sqrt", and "power".
+ */
+extern const prototype_table& get_default_reader();
+/**
+ * Builtin prototype table.
  *
- * The data referenced by the return value is only created once when this
- * function is called for the first time. This might cause problems in very
- * rare stituations (i.e. if functions are added after this first call). In
- * that case, a new initialization can be forced with an "true" argument.
+ * It supports only the builtin GiNaC functions and "pow", "sqrt", and "power".
  */
-extern const prototype_table& get_default_reader(bool force_init = false);
+extern const prototype_table& get_builtin_reader();
 
 } // namespace GiNaC