multiple move/copy/link function

[Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>]

This uses the backreference stuff in 7825, 7834 and 7848 (sorry) to make a
frontend to mv, cp and ln a bit like mmv but using zsh patterns.  Each
parenthesis in the from-pattern can be referred to by a positional
parameter in the to-string.

# function zmv {
# zmv, zcp, zln:
#
# Use zsh pattern matching to move, copy or link files, depending on
# the last two characters of the function name.  The general syntax is
#   zmv '<inpat>' '<outstring>'
# <inpat> is a globbing pattern, so it should be quoted to prevent it from
# immediate expansion, while <outstring> is a string that will be
# re-evaluated and hence may contain parameter substitutions, which should
# also be quoted.  Each set of parentheses in <inpat> (apart from those
# around glob qualifiers and globbing flags) may be referred to by a
# positional parameter in <outstring>, i.e. the first (...) matched is
# given by $1, and so on.  For example,
#   zmv '([a-z])(*).txt' '${(U)1}$2.txt'
# renames algernon.txt to Algernon.txt, boris.txt to Boris.txt and so on.
# The original file matched can be referred to as $f in the second
# argument; accidental or deliberate use of other parameters is at owner's
# risk and is not covered by the (non-existent) guarantee.
#
# Any error --- a substitution resulted in an empty string, a
# substitution did not change the file name, two substitutions gave the
# same result, the destination was an existing regular file and -f was not
# given --- causes the entire function to abort without doing anything.
#
# Options:
#  -f  force overwriting of destination files.  Not currently passed
#      down to the mv/cp/ln command due to vagaries of implementations.
#  -i  interactive: show each line to be executed and ask the user whether
#      to execute it.  Y or y will execute it, anything else will skip it.
#      Note that you just need to type one character.
#  -n  no execution: print what would happen, but don't do it.
#  -q  don't allow bare glob qualifiers in the filename pattern, see below.
#  -s  symbolic, passed down to ln; only works with zln or z?? -L.
#  -v  verbose: print line as it's being executed.
#  -o <optstring>
#      <optstring> will be split into words and passed down verbatim
#      to the cp, ln or mv called to perform the work.  It will probably
#      begin with a `-'.
#  -p <program>
#      Call <program> instead of cp, ln or mv.  Whatever it does, it should
#      at least understand the form '<program> -- <oldname> <newname>',
#      where <oldname> and <newname> are filenames generated.
#  -C
#  -L
#  -M  Force cp, ln or mv, respectively, regardless of the name of the
#      function.
#
# Bugs:
#   Parenthesised expressions can be confused with glob qualifiers, for
#   example a trailing '(*)' is treated as a glob qualifier.  Use -q to
#   turn off glob qualifiers, or (yuk) add a suitable dummy qualifier
#   (e.g. `(.)') or dummy pattern (e.g. `(|)') at the end.
#
#   The second argument is re-evaluated in order to expand the parameters,
#   so quoting may be a bit haphazard.  In particular, a double quote
#   will need an extra level of quoting.
#
#   The pattern is always treated as an extendedglob pattern.
#
# Unbugs:
#   You don't need braces around the 1 in expressions like '$1t' as
#   non-positional parameters may not start with a number, although
#   paranoiacs like the author will probably put them there anyway.

emulate -L zsh
setopt extendedglob

local f g args match mbegin mend files action myname tmpf opt exec
local opt_f opt_i opt_n opt_q opt_s opt_M opt_C opt_L opt_o opt_p
local pat repl errstr
typeset -A from to
integer stat

while getopts ":o:p:MCLfinqsv" opt; do
  if [[ $opt = "?" ]]; then
    print -P "%N: unrecognized option: -$OPTARG" >&2
    return 1
  fi
  eval "opt_$opt=${OPTARG:--$opt}"
done
(( OPTIND > 1 )) && shift $(( OPTIND - 1 ))

[[ -n $opt_q ]] && setopt nobareglobqual
[[ -n $opt_M ]] && action=mv
[[ -n $opt_C ]] && action=cp
[[ -n $opt_L ]] && action=ln
[[ -n $opt_p ]] && action=$opt_p

if (( $# != 2 )); then
  print -P "Usage: %N oldpattern newpattern
  e.g. %N '(*).lis' '\$1.txt'" >&2
  return 1
fi

pat=$1
repl=$2

if [[ -z $action ]]; then
  # We can't necessarily get the name of the function directly, because
  # of no_function_argzero stupidity.
  tmpf=${TMPPREFIX}zmv$$
  print -P %N >$tmpf
  myname=$(<$tmpf)
  rm -f $tmpf

  action=$myname[-2,-1]

  if [[ $action != (cp|mv|ln) ]]; then
    print "Action $action not recognised: must be cp, mv or ln." >&2
    return 1
  fi
fi


if [[ -n $opt_s && $action != ln ]]; then
  print -P "%N: invalid option: -s" >&2
  return 1
fi

files=(${~pat})

if [[ -o bareglobqual && $pat = (#b)(*)\([^\)\|\~]##\) ]]; then
  # strip off qualifiers for use as ordinary pattern
  pat=$match[1]
fi

errs=()

for f in $files; do
  [[ -e $f && $f = (#b)${~pat} ]] || continue
  set -- $match
  eval g=\"$repl\"
  if [[ -z $g ]]; then
    errs=($errs "$f expanded to empty string")
  elif [[ $f = $g ]]; then
    errs=($errs "$f not altered by substitution")
  elif [[ -n $from[$g] && ! -d $g ]]; then
    errs=($errs "$f and $from[$g] both map to $g")
  elif [[ -f $g && -z $opt_f ]]; then
    errs=($errs "file exists: $g")
  fi
  from[$g]=$f
  to[$f]=$g
done

if (( $#errs )); then
  print -P "%N: error(s) in substitution:" >&2
  print -l $errs >&2
  return 1
fi

for f in $files; do
  exec=($action ${=opt_o} $opt_s -- $f $to[$f])
  [[ -n $opt_i$opt_n$opt_v ]] && print -- $exec
  if [[ -n $opt_i ]]; then
    read -q 'opt?Execute? ' || continue
  fi
  if [[ -z $opt_n ]]; then
    $exec || stat=1
  fi
done

return $stat
# }

-- 
Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarroti 2, 56127 Pisa, Italy