Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!csc.ti.com!ti-csl!m2.csc.ti.com!usenet
From: stenger@csc.ti.com (Dan Stenger)
Newsgroups: comp.lang.c++
Subject: RE: C++ gets typecast
Message-ID: <1990Aug8.122043.12643@csc.ti.com>
Date: 8 Aug 90 12:20:43 GMT
Sender: usenet@csc.ti.com (USENET News System)
Organization: TI Computer Science Center, Dallas
Lines: 58
In-Reply-To: <9007230453.AA12697@ucbvax.Berkeley.EDU>

To encourage additional experimentation with parameterized types in the C++
programming community we have made available an implementation of "templates"
as described by Stroustrup in his 1988 USENIX C++ Conference paper
"Parameterized types for C++".  Here is a simple example of this syntax:


template<class T> class Vector<T> {
	T* v;
	int sz;
  public:
	Vector<T>(int);
	T& operator[](int);
	inline T& elem(int i) { return v[i]; }
};

template<class T>
T& Vector<T>::operator[](int i) {
	if (i<0 || sz<=i) error("vector: range error");
	return elem(i);
};

template<class T>
Vector<T>::Vector<T>(size) {
	v = new(T[size]);
};

DECLARE Vector<char*>;   // create definitions for a vector of strings
IMPLEMENT Vector<char*>; // generate code to support vector of strings
Vector<char*> vs(30);	 // declare a vector of 30 strings


This implementation is provided through an enhanced macro facility in a
portable C++ preprocessor.  We started with the DECUS C preprocessor that is
provided in the MIT X Consortium distribution.  First, we made it compliant
with ANSI C (except for tri-graphs).  Next, we made it recognize a #pragma
form with the syntax "#pragma defmacro NAME PROGRAM", where NAME is the macro
keyword to use in the source text and PROGRAM is a program to execute to
translate the macro.  Finally, we wrote the defmacros to translate the
template syntax to standard C++.

Interested parties can find all of this available for anonymous ftp from:

	csc.ti.com	(internet address 128.247.159.141)

in compressed form in the file:

	/pub/cpp.tar.Z

Be forewarned that this is experimental, research software (although we have
used it extensively here at TI) and the standard syntax for parameterized
types is still evolving (the current ANSI proposal is slightly different).
Also, I am willing to help and answer questions but I only have a limited
capacity to deal with them.

	Dan Stenger
	Texas Instruments
	Computer Science Center
	stenger@csc.ti.com