[PATCH 3 of 4] document '!' and 'exact:' encoders/decoders

[Mark Hammond]

# HG changeset patch
# User Mark Hammond <mhammond at skippinet.com.au>
# Date 1240017740 -36000
# Node ID 6fa400a25915cbd5f5d8de0edc0dc46b0093873b
# Parent  5d89dd261ff9eb5967aa7ecc576b1323d94a1b1b
document '!' and 'exact:' encoders/decoders

diff --git a/doc/hgrc.5.txt b/doc/hgrc.5.txt
--- a/doc/hgrc.5.txt
+++ b/doc/hgrc.5.txt
@@ -107,6 +107,10 @@
   localization/canonicalization of files.
 
   Filters consist of a filter pattern followed by a filter command.
+  Filter patterns are tested in the order of the pattern length (eg,
+  'foo/*' is tested before '**') and filtering is stopped after the
+  first match (ie, only one filter will ever be applied to a file)
+
   Filter patterns are globs by default, rooted at the repository
   root. For example, to match any file ending in ".txt" in the root
   directory only, use the pattern "*.txt". To match any file ending
@@ -159,6 +163,39 @@
     [decode]
     **.txt = dumbdecode:
 
+  The filter command "!" disables all previous filter definitions for that
+  pattern. The pattern indicated may still be subject to filtering if it
+  matches other patterns. If you want to disable filtering completely for a
+  file or pattern, add your filter using the 'exact' filters.
+
+  To explain the differences, consider the following examples:
+
+    ## User's Mercurial.ini ##
+    [encode]
+    **.foo = dumbencode:
+    ** = cleverencode:
+
+    ## Tree's .hg/hgrc file ##
+    [encode]
+    **.foo = !
+
+  In the example above, '*.foo' files will have cleverencoding applied; the
+  entry in the .hgrc file has the effect of disabling the **.foo pattern in
+  Mercurual.ini, so '*.foo' files then match the '**' pattern.  However,
+  consider the following configuration:
+
+    ## User's Mercurial.ini ##
+    [encode]
+    **.foo = dumbencode:
+    ** = cleverencode:
+
+    ## Tree's .hg/hgrc file ##
+    [encode]
+    **.foo = exact:
+
+  In this example, '*.foo' files will have the 'exact' encoding applied,
+  meaning the contents of the file are not touched by the encoding process.
+
 [[defaults]]
 defaults::
   Use the [defaults] section to define command defaults, i.e. the