-.\" $OpenBSD: yacc.1,v 1.23 2010/07/20 12:53:43 jmc Exp $
+.\" $OpenBSD: yacc.1,v 1.24 2010/07/21 19:44:47 jmc Exp $
.\"
.\" Copyright (c) 1989, 1990 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" from: @(#)yacc.1 5.7 (Berkeley) 7/30/91
.\"
-.Dd $Mdocdate: July 20 2010 $
+.Dd $Mdocdate: July 21 2010 $
.Dt YACC 1
.Os
.Sh NAME
.Op Fl or
are extensions to that specification.
.Sh HISTORY
+Yacc was originally developed at AT&T by Stephen C. Johnson.
+.Pp
Berkeley Yacc was originally developed using PCC on a VAX with the
intent of being as compatible as possible with AT&T Yacc.
Much is owed to the unflagging efforts of Keith Bostic.