[Bash-completion-devel] for help about the _filedir() function

[wxuyec]

hi everyone,

I want to do something about complete Chinese in bash and 
am reading the function of _filedir(). I really don't understand
this line:

    toks=( ${toks[@]-} $( 
      compgen -d -- "$(quote_readline "$cur")" | {
      while read -r tmp; do                 
          echo $tmp
      done            
  }                   
  ))
can anyone help me with that? or what book should I read?
thank you in advance.

kind regards,
YC