RCSFILE(4) RCSFILE(4)
NAME
rcsfile - format of RCS file
DESCRIPTION
An RCS file is an ASCII file. Its contents are described by
the grammar below. The text is free format, i.e., spaces,
tabs and new lines have no significance except in strings.
Strings are enclosed by `@'. If a string contains a `@', it
must be doubled.
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; `<' and `>'
enclose nonterminals.
<rcstext> ::= <admin> {<delta>}* <desc> {<deltatext>}*
<admin> ::= head {<num>};
access {<id>}*;
symbols {<id> : <num>}*;
locks {<id> : <num>}*;
comment {<string>};
<delta> ::= <num>
date <num>;
author <id>;
state {<id>};
branches {<num>}*;
next {<num>};
<desc> ::= desc <string>
<deltatext> ::= <num>
log <string>
text <string>
<num> ::= {<digit>{.}}+
<digit> ::= 0 | 1 | ... | 9
<id> ::= <letter>{<idchar>}*
<letter> ::= A | B | ... | Z | a | b | ... | z
<idchar> ::= Any printing ASCII character except space,
tab, carriage return, new line, and <special>.
<special> ::= ; | : | , | @
<string> ::= @{any ASCII character, with `@' doubled}*@
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RCSFILE(4) RCSFILE(4)
Identifiers are case sensitive. Keywords are in lower case
only. The sets of keywords and identifiers may overlap.
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).
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 2(n-1) 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.
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RCSFILE(4) RCSFILE(4)
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: 1.3 ; Release Date: 87/02/17 .
c
Copyright 1982 by Walter F. Tichy.
SEE ALSO
ci(1), co(1), ident(1), rcs(1), rcsdiff(1), rcsintro(1),
rcsmerge(1), rlog(1).
ORIGIN
4.2 BSD
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RCSFILE(4) RCSFILE(4)
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