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Package TWiki::Store::RcsLite

This package does not publish any methods. It implements the virtual methods of the TWiki::Store::RcsFile superclass.

Simple replacement for RCS. Doesn't support:

  • branches
  • locking
Neither of which are used (or needed) by TWiki.

This module doesn't know anything about the content of the topic

There is one of these object for each file stored under RCSLite.

This object is PACKAGE PRIVATE to Store, and should NEVER be used from anywhere else.


  • need to tidy up dealing with \n for differences
  • still have difficulty on line ending at end of sequences, consequence of doing a line based diff

File format

rcstext    ::=  admin {delta}* desc {deltatext}*
admin      ::=  head {num};
                { branch   {num}; }
                access {id}*;
                symbols {sym : 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 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
id         ::=  {num} idchar {idchar | num }*
sym        ::=  {digit}* idchar {idchar | digit }*
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 can overlap. In most environments RCS uses the ISO 8859/1 encoding: visible graphic characters are codes 041-176 and 240-377, and white space characters are codes 010-015 and 040.

Dates, which appear after the date keyword, are of the form Y.mm.dd.hh.mm.ss, where Y is the year, mm the month (01-12), dd the day (01-31), hh the hour (00-23), mm the minute (00-59), and ss the second (00-60). Y contains just the last two digits of the year for years from 1900 through 1999, and all the digits of years thereafter. Dates use the Gregorian calendar; times use UTC.

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.

Revisions consist of a sequence of 'a' and 'd' edits that need to be applied to rev N+1 to get rev N. Each edit has an offset (number of lines from start) and length (number of lines). For 'a', the edit is followed by length lines (the lines to be inserted in the text). For example:

d1 3 means "delete three lines starting with line 1 a4 2 means "insert two lines at line 4' xxxxxx is the new line 4 yyyyyy is the new line 5

ObjectMethod finish ()

Break circular references.

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Topic revision: r5 - 2013-10-14 - TWikiContributor
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