[PATCH] vcs_info docs: applied-string/unapplied-string: Correct an omission in the documentation and add an example.

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

The example code is a reduced version of my function from workers/47519,
with one bug fixed.  (In workers/47519, if $1 doesn't contain spaces -
which is the case under hg mq - then $H and $s will be set to the same
value.)
---
 Doc/Zsh/contrib.yo     | 13 ++++++++---
 Misc/vcs_info-examples | 51 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/Doc/Zsh/contrib.yo b/Doc/Zsh/contrib.yo
index 586ac06f5..4c7443ffc 100644
--- a/Doc/Zsh/contrib.yo
+++ b/Doc/Zsh/contrib.yo
@@ -1652,10 +1652,15 @@ Called in the tt(git) (with tt(stgit) or during rebase or merge), and tt(hg)
 is generated; the tt(use-quilt) zstyle must be true for tt(quilt) (the tt(mq)
 and tt(stgit) backends are active by default).
 
-This hook gets the names of all applied patches which tt(vcs_info) collected
-so far in the opposite order, which means that the first argument is the
+The arguments to this hook describe applied patches 
+in the opposite order, which means that the first argument is the
 top-most patch and so forth.
 
+When the patches' log messages can be extracted, those are embedded
+within each argument after a space, so each argument is of the form
+`var(patch-name) var(first line of the log message)', where var(patch-name)
+contains no whitespace.
+
 When setting tt(ret) to non-zero, the string in
 tt(${hook_com[applied-string]}) will be
 available as tt(%p) in the tt(patch-format) and tt(nopatch-format) styles.
@@ -1669,9 +1674,11 @@ tt(mq)) backend and in tt(quilt) support when the tt(unapplied-string) is
 generated; the tt(get-unapplied) style must be true.
 
 This hook gets the names of all unapplied patches which tt(vcs_info)
-collected so far in order, which means that the first argument is
+in order, which means that the first argument is
 the patch next-in-line to be applied and so forth.
 
+The format of each argument is as for tt(gen-applied-string), above.
+
 When setting tt(ret) to non-zero, the string in
 tt(${hook_com[unapplied-string]}) will be available as tt(%u) in the
 tt(patch-format) and tt(nopatch-format) styles.
diff --git a/Misc/vcs_info-examples b/Misc/vcs_info-examples
index 94b8a7b5e..36b6fbc51 100644
--- a/Misc/vcs_info-examples
+++ b/Misc/vcs_info-examples
@@ -282,6 +282,54 @@ function +vi-hg-branchhead() {
 }
 
 
+### Show information about patch series
+# This is used with with hg mq, quilt, and git rebases and conflicts.
+#
+# All these cases have a notion of a "series of patches/commits" that is being
+# applied.  The following shows the information about the most recent patch to
+# have been applied:
+zstyle ':vcs_info:*+gen-applied-string:*' hooks gen-applied-string
+function +vi-gen-applied-string() {
+  # Separate the patch id from the patch log message.
+  if [[ $1 == *\ * ]]; then
+    local patch_name_or_filename="${1%% *}"
+    local patch_description="${1#* }"
+  else
+    local patch_name_or_filename="$1"
+    local patch_description=""
+  fi
+
+  # Apply escaping; see `Oddities' in the manual.
+  patch_name_or_filename=${patch_name_or_filename//'%'/%%}
+  patch_description=${patch_description//'%'/%%}
+
+  # Apply different colouring to the patch description.
+  if [[ -n ${patch_description} ]]; then
+    patch_description="%F{yellow}${patch_description}%f"
+  fi
+
+  # Re-assemble $1, escaped and coloured.
+  hook_com[applied-string]="${patch_name_or_filename} ${patch_description}"
+  ret=1
+}
+# The value of hook_com[applied-string] is incorporated into the %m expando
+# (see the 'patch-format' style for details), which is not included in the
+# 'formats' and 'actionformats' style by default, so to actually use this,
+# you'll need to add %m (or %Q under quilt in add-on mode) to your 'formats'
+# and 'actionformats' styles, as in:
+# 
+#     zstyle ':vcs_info:*' actionformats ' (%s)-[%b|%a]%u%c- %m'
+#     zstyle ':vcs_info:*' formats ' (%s)-[%b]%u%c- %m'
+# 
+# Or you could add it as a new word, as in:
+#
+#     zstyle ':vcs_info:*' actionformats ' (%s)-[%b|%a]%u%c-' '%m'
+#     zstyle ':vcs_info:*' formats ' (%s)-[%b]%u%c-' '%m'
+#
+# In the latter case, you will need to arrange to print ${vcs_info_msg_1_} in
+# addition to ${vcs_info_msg_0_}; see the top of this file for details.
+
+
 ### Run vcs_info selectively to increase speed in large repos ################
 
 # The following example shows a possible setup for vcs_info which displays
@@ -544,6 +592,9 @@ function +vi-set-quilt-patches() {
 # This would take care of all the dedicated-patches-directory-in-${HOME}
 # from earlier examples, too.
 
+# Finally, the "Show information about patch series" example above this section
+# may also be useful.
+
 
 ### Using vcs_info from CVS ##################################################