From 4c85c757e55c1b75635672624632e3e6c92c5dd1 Mon Sep 17 00:00:00 2001
From: =?utf8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Sun, 2 Apr 2017 16:52:34 -0700
Subject: [PATCH] doc: refactor and update expand and unexpand --help

* src/expand-common.c (emit_tab_list_info): A new function to
output the extended info on --tab=LIST, including the new
'+' and '/' prefixes.
* src/expand-common.h: Declare the above.
* src/expand.c (usage:): Call emit_tab_list_info and
match alignment with that used in unexpand --help.
* src/unexpand.c (usage): Likewise.
---
 src/expand-common.c | 17 +++++++++++++++++
 src/expand-common.h |  4 ++++
 src/expand.c        |  8 +++-----
 src/unexpand.c      |  2 +-
 4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/src/expand-common.c b/src/expand-common.c
index 05e5bec2d8..8c83fb3652 100644
--- a/src/expand-common.c
+++ b/src/expand-common.c
@@ -382,3 +382,20 @@ cleanup_file_list_stdin (void)
     if (have_read_stdin && fclose (stdin) != 0)
       die (EXIT_FAILURE, errno, "-");
 }
+
+
+extern void
+emit_tab_list_info (void)
+{
+  /* suppress syntax check for emit_mandatory_arg_note() */
+  fputs (_("\
+  -t, --tabs=LIST  use comma separated list of tab positions\n\
+"), stdout);
+  fputs (_("\
+                     The last specified position can be prefixed with '/'\n\
+                     to specify a tab size to use after the last\n\
+                     explicitly specified tab stop.  Also a prefix of '+'\n\
+                     can be used to align remaining tab stops relative to\n\
+                     the last specified tab stop instead of the first column\n\
+"), stdout);
+}
diff --git a/src/expand-common.h b/src/expand-common.h
index 5eec99d6ba..8cc6ebe198 100644
--- a/src/expand-common.h
+++ b/src/expand-common.h
@@ -70,3 +70,7 @@ next_file (FILE *fp);
 /* */
 extern void
 cleanup_file_list_stdin (void);
+
+
+extern void
+emit_tab_list_info (void);
diff --git a/src/expand.c b/src/expand.c
index 2b7781ca51..1e783169a2 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -78,12 +78,10 @@ Convert tabs in each FILE to spaces, writing to standard output.\n\
       emit_mandatory_arg_note ();
 
       fputs (_("\
-  -i, --initial       do not convert tabs after non blanks\n\
-  -t, --tabs=NUMBER   have tabs NUMBER characters apart, not 8\n\
-"), stdout);
-      fputs (_("\
-  -t, --tabs=LIST     use comma separated list of explicit tab positions\n\
+  -i, --initial    do not convert tabs after non blanks\n\
+  -t, --tabs=N     have tabs N characters apart, not 8\n\
 "), stdout);
+      emit_tab_list_info ();
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
       emit_ancillary_info (PROGRAM_NAME);
diff --git a/src/unexpand.c b/src/unexpand.c
index fd334ddc80..60c9422ef4 100644
--- a/src/unexpand.c
+++ b/src/unexpand.c
@@ -90,8 +90,8 @@ Convert blanks in each FILE to tabs, writing to standard output.\n\
   -a, --all        convert all blanks, instead of just initial blanks\n\
       --first-only  convert only leading sequences of blanks (overrides -a)\n\
   -t, --tabs=N     have tabs N characters apart instead of 8 (enables -a)\n\
-  -t, --tabs=LIST  use comma separated LIST of tab positions (enables -a)\n\
 "), stdout);
+      emit_tab_list_info ();
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
       emit_ancillary_info (PROGRAM_NAME);
-- 
2.47.2