[7891] avoid multiple levels of quoting in shell script

[gavinsmith0123]

Revision: 7891
          http://svn.sv.gnu.org/viewvc/?view=rev&root=texinfo&revision=7891
Author:   gavin
Date:     2017-07-01 16:13:09 -0400 (Sat, 01 Jul 2017)
Log Message:
-----------
avoid multiple levels of quoting in shell script

Modified Paths:
--------------
    trunk/ChangeLog
    trunk/tp/Texinfo/Convert/XSParagraph/configure.ac

Modified: trunk/ChangeLog
===================================================================
--- trunk/ChangeLog     2017-07-01 14:37:17 UTC (rev 7890)
+++ trunk/ChangeLog     2017-07-01 20:13:09 UTC (rev 7891)
@@ -1,5 +1,16 @@
 2017-07-01  Gavin Smith  <address@hidden>
 
+       * tp/Texinfo/Convert/XSParagraph/configure.ac (fetch_conf): Put
+       all sed commands within an environment variable, 'sed_script'.
+       Assign 'sed_script' from a double-quoted string, using shell 
+       variables to include awkward characters.  This avoids there 
+       being multiple level of quoting present which can be extremely 
+       confusing, i.e., autoconf's quadrigraphs, quoting within the 
+       backquoted string where sed is called, as well as sed's own 
+       escaping of special characters. 
+
+2017-07-01  Gavin Smith  <address@hidden>
+
        * info/t/c-u-m-x-scroll-forward.sh, info/t/inc-sea-insensitive.sh, 
        info/t/search-split-after-index.sh, info/t/split-footnotes.sh, 
        info/t/star-note-non-whitespace.sh, info/t/tab-argument.sh, 

Modified: trunk/tp/Texinfo/Convert/XSParagraph/configure.ac
===================================================================
--- trunk/tp/Texinfo/Convert/XSParagraph/configure.ac   2017-07-01 14:37:17 UTC 
(rev 7890)
+++ trunk/tp/Texinfo/Convert/XSParagraph/configure.ac   2017-07-01 20:13:09 UTC 
(rev 7891)
@@ -1,6 +1,6 @@
 # configure.ac for XSParagraph
 #
-# Copyright 2015, 2016 Free Software Foundation, Inc.
+# Copyright 2015, 2016, 2017 Free Software Foundation, Inc.
 #
 # This file is free software; as a special exception the author gives
 # unlimited permission to copy and/or distribute it, with or without
@@ -14,19 +14,25 @@
 AM_INIT_AUTOMAKE
 AC_CONFIG_MACRO_DIR([m4])
 
+b='\'
+o='@<:@' dnl quadrigraph for [ - see autoconf documentatoin
+c='@:>@' dnl quadrigraph for ]
+
+# This turns a string like "cc='cc';" into a string like "cc".
+# Afterwards, convert \ into / in case \ is a path separator,
+# so it is not interpreted as a special character by the shell.
+
+sed_script="
+s/^$o^=$c*= *//
+s/^'//
+s/ *; *$//
+s/'$//
+s/$b$b/$b//g"
+
 fetch_conf ()
 {
           conf_value=`${PERL} -V:$1`
-          # This turns a string like "cc='cc';" into a string like "cc".
-          # Afterwards, convert \ into / in case \ is a path separator,
-          # so it is not interpreted as a special character by the shell.
-          conf_value=`echo $conf_value \
-              | sed -e 's/^@<:@^=@:>@*= *//'   \
-                    -e 's/^'\\''//'            \
-                    -e 's/ *; *$//'            \
-                    -e 's/'\\''$//'            \
-                    -e 's/\\\\/\\//g'          `
-          #echo got "$conf_value"
+          conf_value=`echo $conf_value | sed "$sed_script"`
 } 
 
 AC_DEFUN([lookup_perl_conf],