FIX: todo_completion problem with Bash 3.1

Regexp matching changed from 3.1 to 3.2. Make it work for Bash 3.1 by using an intermediate variable, as in 394c4c748a.
Cp. http://tech.groups.yahoo.com/group/todotxt/message/4211

tests/t1100-replace.sh

@@ -164,12 +164,4 @@ TODO: Replaced task with:
 1 (A) 2010-07-04 this also has a new date
 EOF
 
-echo '2009-02-13 this is just a new one' > todo.txt
-test_todo_session 'replace with prepended priority and date replaces existing date' <<EOF
->>> todo.sh replace 1 '(B) 2010-07-04 this also has a new date'
-1 2009-02-13 this is just a new one
-TODO: Replaced task with:
-1 (B) 2010-07-04 this also has a new date
-EOF
-
 test_done

todo.sh

@@ -389,22 +389,21 @@ replaceOrPrepend()
   else
     input=$*
   fi
+  cleaninput "for sed"
 
   # Retrieve existing priority and prepended date
-  local -r priAndDateExpr='^\((.) \)\{0,1\}\([0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} \)\{0,1\}'
-  priority=$(sed -e "$item!d" -e "${item}s/${priAndDateExpr}.*/\\1/" "$TODO_FILE")
-  prepdate=$(sed -e "$item!d" -e "${item}s/${priAndDateExpr}.*/\\2/" "$TODO_FILE")
+  priority=$(sed -e "$item!d" -e $item's/^\((.) \)\{0,1\}\([0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} \)\{0,1\}.*/\1/' "$TODO_FILE")
+  prepdate=$(sed -e "$item!d" -e $item's/^\((.) \)\{0,1\}\([0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} \)\{0,1\}.*/\2/' "$TODO_FILE")
 
-  if [ "$prepdate" -a "$action" = "replace" ] && [ "$(echo "$input"|sed -e "s/${priAndDateExpr}.*/\\1\\2/")" ]; then
-      # If the replaced text starts with a [priority +] date, it will replace
-      # the existing date, too.
+  if [ "$prepdate" -a "$action" = "replace" ] && [ "$(echo "$input"|sed -e 's/^\([0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\}\)\{0,1\}.*/\1/')" ]; then
+    # If the replaced text starts with a date, it will replace the existing
+    # date, too.
     prepdate=
   fi
 
   # Temporarily remove any existing priority and prepended date, perform the
   # change (replace/prepend) and re-insert the existing priority and prepended
   # date again.
-  cleaninput "for sed"
   sed -i.bak -e "$item s/^${priority}${prepdate}//" -e "$item s|^.*|${priority}${prepdate}${input}${backref}|" "$TODO_FILE"
   if [ $TODOTXT_VERBOSE -gt 0 ]; then
     getNewtodo "$item"

todo_completion

@@ -14,14 +14,15 @@ _todo()
         rm depri dp do help list ls listaddons listall lsa listcon  \
         lsc listfile lf listpri lsp listproj lsprj move \
         mv prepend prep pri p replace report shorthelp"
+    local -r MOVE_COMMAND_PATTERN='^(move|mv)$'
 
     local _todo_sh=${_todo_sh:-todo.sh}
     local completions
     if [ $COMP_CWORD -eq 1 ]; then
         completions="$COMMANDS $(eval TODOTXT_VERBOSE=0 $_todo_sh command listaddons) $OPTS"
     elif [[ $COMP_CWORD -gt 2 && ( \
-        "${COMP_WORDS[COMP_CWORD-2]}" =~ ^(move|mv)$ || \
-        "${COMP_WORDS[COMP_CWORD-3]}" =~ ^(move|mv)$ ) ]]; then
+        "${COMP_WORDS[COMP_CWORD-2]}" =~ $MOVE_COMMAND_PATTERN || \
+        "${COMP_WORDS[COMP_CWORD-3]}" =~ $MOVE_COMMAND_PATTERN ) ]]; then
         # "move ITEM# DEST [SRC]" has file arguments on positions 2 and 3.
         completions=$(eval TODOTXT_VERBOSE=0 $_todo_sh command listfile)
     else