mk/su-quote-rndtrip.sh

   1 #!/bin/sh -
   2 #@ Round trip quote strings in POSIX shell.  E.g.,
   3 #@    set -- x 'a \ b' "foo'" "\\'b\\a\\r\\" Aä
   4 #@    printf "%s: <%s><%s><%s><%s><%s>\n" "$#" "${1}" "${2}" "${3}" "$4" "$5"
   5 #@    saved_parameters=`quote_rndtrip "$@"`
   6 #@    eval "set -- $saved_parameters"
   7 #@    printf "%s: <%s><%s><%s><%s><%s>\n" "$#" "${1}" "${2}" "${3}" "$4" "$5"
   8 #
   9 # 2017 Robert Elz (kre).
  10 # 2017 - 2020 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
  11 # Public Domain
  12
  13 # Though slower use a subshell version instead of properly restoring $IFS
  14 # and flags, as elder shells may not be able to properly restore flags via
  15 # "set +o" as later standardized in POSIX, and it seems overkill to handle
  16 # all possible forms of output "set +o" may or may not actually generate.
  17 quote__rndtrip() (
  18    case "$1" in
  19    *\'*) ;;
  20    *) printf "'%s'" "$1"; return 0;;
  21    esac
  22    a="$1" s= e=
  23    while case "$a" in
  24       \'*)  a=${a#?}; s="${s}\\\\'";;
  25       *\')  a=${a%?}; e="${e}\\\\'";;
  26       '')   printf "${s}${e}"; exit 0;;
  27       *) false;;
  28       esac
  29    do
  30       continue
  31    done
  32    IFS=\'
  33    set -f
  34    set -- $a
  35    r="${1}"
  36         shift
  37    for a
  38    do
  39       r="${r}'\\''${a}"
  40    done
  41    printf "${s}'%s'${e}" "${r}"
  42    exit 0
  43 )
  44
  45 quote_rndtrip() (
  46    j=
  47    for i
  48    do
  49       [ -n "$j" ] && printf ' '
  50       j=' '
  51       quote__rndtrip "$i"
  52    done
  53 )
  54
  55 quote_string() (
  56    j=
  57    for i
  58    do
  59       [ -n "$j" ] && printf '\\ '
  60       j=' '
  61       quote__rndtrip "$i"
  62    done
  63 )
  64
  65 # s-sh-mode