.zshrc.sh

# list files grouped by extension, and sorted in reverse chronological
# order, mostly
function dc () {
  local dir=${1:-.}
  local FIRST=1;
  local l f files exts extfiles extorder;
  (cd $dir
      IFS="
"
      files=(*~(*~)(N))
      files=(${files:#\#*\#})
      files=($(ls -tcd1 $files))

      # list a group of files, printing a --- separator after the
      # first call. restrict to contents of $files, and remove our
      # output from $files afterwards
      _lsgroup () {
          # zsh array expansion is much faster than grep -Ff

          # llua@#zsh says: use l=( "${(@)l:*files}" ) (but this only
          # makes a difference if there is an empty string in one of
          # the arrays)

          # filter $l through $files
          l=(${l:*files})

          # remove elements of $l from $files
          files=(${files:|l})
          
          if [[ "$#l" > 0 ]]; then
              { [[ $FIRST -eq 0 ]] &&
                    {perl -le "print \"-\"x$COLUMNS"} || FIRST=0 }
              ls --color=always -rtcd $l
          fi
      }

      # make a list of extensions, in order of most recently appearing
      # first. TODO: remove extensions with odd characters, which may
      # not actually be extensions
      extfiles=(${(M)files:#*.*})
      dirs=(*(-/N)) # remove directories from extension list
      extfiles=(${extfiles:|dirs})
      extorder=()
      while [[ $#extfiles -gt 0 ]]; do
          f=$extfiles[1];
          ext=${f##*.}
          extorder+=$ext
          extfiles=(${extfiles:#*.$ext})
      done

      # now display files with each extension in our list
      for ext in ${(Oa)extorder}; do
          l=(*.$ext(N-^/)) # exclude directories
          _lsgroup
      done

      # files with no extension, not matching next two groups
      rest=(*(-*N) *(-/N))
      l=(${files:|rest})
      _lsgroup

      # executables (- means dereference symlinks)
      l=(*(-*N))
      _lsgroup

      # directories
      l=(*(-/N));
      _lsgroup
 )
}

Produces output like this:

Makefile.in  config.h.in
------------------------------------------------------------------------
autogen.sh
------------------------------------------------------------------------
README.FAQ
------------------------------------------------------------------------
config.sub
------------------------------------------------------------------------
aclocal.m4
------------------------------------------------------------------------
INSTALL  Changes  COPYING  MANIFEST
------------------------------------------------------------------------
install-sh  configure
------------------------------------------------------------------------
libev  doc  src  libptytty