## File: intro.inc

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cwebx 3.52-3
 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990 \def\currentCWEBxversion{x3.52} % see also version_string end of this file \def\hang{\hangindent 3em\indent\ignorespaces} \def\pb{$\.|\ldots\.|$} % C brackets (|...|) \def\LKC.{Levy/Knuth \.{CWEB}} \def\:#1{\.{@@#1}'} \def\title{\me. (Version \currentCWEBxversion)} \def\topofcontents {\topglue 0pt plus .5 fill \centerline{\titlefont The {\ttitlefont \me.} program} \vskip 15pt \centerline{(\.{CWEB} version \currentCWEBxversion)} \vfill } \def\botofcontents {\vfill\noindent Copyright \copyright\ 1987,\thinspace1990 Silvio Levy and Donald E. Knuth \par\noindent Copyright 1994 Marc A. A. van Leeuwen \bigskip\noindent Permission is granted to make and distribute verbatim copies of this document provided that the copyright notice and this permission notice are preserved on all copies. \smallskip\noindent Permission is granted to copy and distribute modified versions of this document under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. } @* Introduction. @:title@> This is the main source text for the program \.{\me.}, one of the two text processing tools that constitute the \.{CWEB} system. This version of the system, identified as \.{CWEB}\currentCWEBxversion, was written by Marc van Leeuwen. The history of this system is somewhat complicated, and starts with the \.{WEB} system created by D.~E. Knuth (for the programming language Pascal); the program corresponding to the current program in that system was called~\myroots. That program was converted into \.{\me.}, written in and for the \Cee~language, by Silvio Levy, and further developed under joint responsibility with Knuth. Based on \.{CWEB}~2.1 by Levy and Knuth, a version adapted to \caps{ANSI~C} was made by Frank Jensen. That version has served as the starting point for the current author; an intermediate version between it and the current version was made public under the name \.{CWEB}~3.x. Helpful comments and suggestions by Gareth McCaughan, Werner Lemberg, and Andreas Scherer were greatly appreciated. The name \.{CWEB}~3.x was an unfortunate choice, since the Levy/Knuth version of \.{CWEB} had also been independently developed further, and it is currently being distributed as \.{CWEB}~3.4f. Both these branches have retained the basic functionality of the version of \.{CWEB} they were both derived from, making only minor (but different) additions and changes. Realising that this divergence is undesirable and confusing, the development of this branch from \.{CWEB}~3.x to the current version was mainly concerned with improving compatibility and peaceful coexistence with the other branch. First of all the name was changed by moving the character~x' to the front of the version number, so that this branch of the system can be referred to as \.{CWEBx}' without mentioning a complete version number; for clarity we shall refer to the other branch as \LKC.'. @^Levy/Knuth \.{CWEB}@> Secondly, all the extensions of \LKC. were included, although in a few cases in a slightly different form to avoid name conflicts with features already present in \.{CWEB}~3.x. Thirdly, in order to accomodate existing programs written for \LKC., among which are those of Knuth's impressive collection called the Stanford GraphBase, a compatibility mode'' was added, selectable by a command line option (\.{+c}), in which the remaining, mostly trivial, differences in syntax and semantics are removed, and the system attempts to be an alternative implementation for exactly the same language as accepted by \LKC., at the price of losing a few possibilities particular to~\.{CWEBx}. The major version number 3' now corresponds to the same version number of \LKC., and since no further extension of the possibilities of that system are anticipated, we do not expect that compatibility will ever require any further increase of this major version number. The Stanford GraphBase @^Stanford GraphBase@> states that it requires \.{CWEB} version 3.0 or greater; this version of \.{CWEBx} can fully process it in a satisfactory way, using compatibility mode. The banner line'' defined here should be changed whenever changes to \.{\me.} are made publicly available. Users who are discontent with some aspect of the program are encouraged to make the necessary modifications in their copy of the source files; if this involves an improvement of the implementation, they are kindly requested to inform the author responsible for the current version. If they choose to make the resulting program available under the name \.{\me.}, they should modify the non-numeric prefix of the version specification. @d version_string "x3.52" `