rcsfile(4) DG/UX R4.11MU05 rcsfile(4)
NAME
rcsfile - format of RCS file
DESCRIPTION
An RCS file's contents are described by the grammar below.
The text is free format: space, backspace, tab, newline, vertical
tab, form feed, and carriage return (collectively, white space) have
no significance except in strings. However, an RCS file must end in
a newline character.
Strings are enclosed by @. If a string contains a @, it must be
doubled; otherwise, strings may contain arbitrary binary data.
The meta syntax uses the following conventions: `|' (bar) separates
alternatives; `{' and `}' enclose optional phrases; `{' and `}*'
enclose phrases that may be repeated zero or more times; `{' and '}+'
enclose phrases that must appear at least once and may be repeated;
Terminal symbols are in boldface; nonterminal symbols are in italics.
rcstext ::= admin {delta}* desc {deltatext}*
admin ::= head {num};
{ branch {num}; }
access {id}*;
symbols {id : num}*;
locks {id : num}*; {strict ;}
{ comment {string}; }
{ expand {string}; }
{ newphrase }*
delta ::= num
date num;
author id;
state {id};
branches {num}*;
next {num};
{ newphrase }*
desc ::= desc string
deltatext ::= num
log string
{ newphrase }*
text string
num ::= {digit{.}}+
digit ::= 0 | 1 | ... | 9
id ::= letter{idchar}*
letter ::= any letter
idchar ::= any visible graphic character except special
special ::= $ | , | . | : | ; | @
string ::= @{any character, with @ doubled}*@
newphrase ::= id word* ;
word ::= id | num | string | :
Identifiers are case sensitive. Keywords are in lower case only.
The sets of keywords and identifiers may overlap. In most
environments RCS uses the ISO 8859/1 encoding: letters are octal
codes 101-132, 141-172, 300-326, 330-366 and 370-377, visible graphic
characters are codes 041-176 and 240-377, and white space characters
are codes 010-015 and 040.
The newphrase productions in the grammar are reserved for future
extensions to the format of RCS files. No newphrase will begin with
any keyword already in use.
The delta nodes form a tree. All nodes whose numbers consist of a
single pair (e.g., 2.3, 2.1, 1.3, etc.) are on the trunk, and are
linked through the next field in order of decreasing numbers. The
head field in the admin node points to the head of that sequence
(i.e., contains the highest pair). The branch node in the admin node
indicates the default branch (or revision) for most RCS operations.
If empty, the default branch is the highest branch on the trunk.
All delta nodes whose numbers consist of 2n fields (n>=2) (e.g.,
3.1.1.1, 2.1.2.2, etc.) are linked as follows. All nodes whose
first 2n-1 number fields are identical are linked through the next
field in order of increasing numbers. For each such sequence, the
delta node whose number is identical to the first 2n-2 number fields
of the deltas on that sequence is called the branchpoint. The
branches field of a node contains a list of the numbers of the first
nodes of all sequences for which it is a branchpoint. This list is
ordered in increasing numbers.
Example:
Head
|
|
v / \
--------- / \
/ \ / \ | | / \ / \
/ \ / \ | 2.1 | / \ / \
/ \ / \ | | / \ / \
/1.2.1.3\ /1.3.1.1\ | | /1.2.2.2\ /1.2.2.1.1.1\
--------- --------- --------- --------- -------------
^ ^ | ^ ^
| | | | |
| | v | |
/ \ | --------- / \ |
/ \ | \ 1.3 / / \ |
/ \ ---------\ / / \-----------
/1.2.1.1\ \ / /1.2.2.1\
--------- \ / ---------
^ | ^
| | |
| v |
| --------- |
| \ 1.2 / |
----------------------\ /---------
\ /
\ /
|
|
v
---------
\ 1.1 /
\ /
\ /
\ /
Fig. 1: A revision tree
IDENTIFICATION
Author: Walter F. Tichy, Purdue University, West Lafayette, IN,
47907.
Revision Number: 1997/10/18; Release Date: 08:52:05.
Copyright © 1982, 1988, 1989 by Walter F. Tichy.
Copyright © 1990, 1991 by Paul Eggert.
SEE ALSO
ci(1), co(1), ident(1), rcs(1), rcsdiff(1), rcsmerge(1), rlog(1),
Walter F. Tichy, RCS--A System for Version Control, Software
--Practice & Experience 15, 7 (July 1985), 637-654.
Licensed material--property of copyright holder(s)