Re: more splitting

[Ray Andrews <rayandrews@xxxxxxxxxxx>]

    Thanks all.  Very nice explanation Dana. 
      I'm 90% there.
      
    
> No, actually, it can't have been designed differently.  Pipes (and all
file descriptors) are an operating system construct, they don't know
what's on either end, they just move bytes.
    I mean that arrays might have been designed to carry a separator
    character between elements.  ASCII FF maybe.  So when piped,
    reconstructing an array would be easier.  Mind, this is the
    shallowest of speculations, there could be very good reasons why
    that's not done.  I'm not whining.    Anyway the point is that I now
    understand that information IS thrown away -- splitting information
    is lost, not by virtue of some magic characters being removed, but
    by virtue of C level storage information being lost.  The socks
    don't know what drawer they came from.  I get it.
    
    
      %  var=("a b" c$'\n''d e f'' ''g h' ij)
      
      % hex var
      
      'a b'
      $'c\nd e f g h'
      ij
      
      -----------------------------
      
      000000  61  20  62
               a       b
      000003
      000000  63  0a  64  20  65  20  66  20  67  20  68
               c  \n   d       e       f       g       h
      00000b
      000000  69  6a
               i   j
      000002
      
      ... The space after the 'b' is gone forever -- it has been taken
      as an instruction to split, NOT as a literal char.  The ' $'\n' '
      construction has been taken as an instruction to add ASCII char
      0a.  The space beween 'f' and 'g' is quoted therefore a printed
      character, not an instruction to split.  The next space is
      unquoted therefore an instruction to split, and it's gone.
      
      % print -n $var
      a b c
      d e f g h ij#   # What's the hash for?
      
      % hex var
      
      'a b'
      $'c\nd e f g h'
      ij
      ...
      
      ... 'a b' is displayed quoted because of the space -- the ticks
      aren't 'real' .  Thus 'ij' needs no ticks.
      
       2 /aWorking/Zsh/Source/Wk 6 % var2=( $=var ); hex var2
      
      a
      b
      c
      d
      e
      f
      g
      h
      ij
      
      ... as expected, except that the newline disappeared.
      
      % var2=( ${(f)var} ); hex var2
      
      'a b c'
      'd e f g h ij'
      
      -----------------------------
      
      000000  61  20  62  20  63
               a       b       c
      000005
      000000  64  20  65  20  66  20  67  20  68  20  69  6a
               d       e       f       g       h       i   j
      00000c
      
      ... love it.  Split on newline.  All spaces preserved. One thing
      tho: when $var is created, would not the splitting spaces vanish?
      But we see the space between 'b' and 'c' remains in var2. 
      Likewise the space between 'h' and 'i' -- how are they retained?
      Or are they put back for display?  
      
      I'm not at the summit, but I'm at the South Col.
      
      
       % typeset -p var 
      typeset -a var=( 'a b' $'c   \n  d e f     g h' ij ) # stretch out
      for comp.
      % var=         ( "a b"    c$'\n''d e f'' ''g h' ij ) # stretched
      ...     
    
      
    ... so typeset output very close to original variable
    creation keystrokes.  Better! Running output of typeset -p to create
    a new array, it's identical to the original.  :-)  Typeset edits my
    input string while retaining the product exactly.  Love it.  IOW,
    typeset returns what I should have typed in the first place.  That
    explains the movement of the dollar too, which has always baffled
    me.  
    
    95%
    
    So a mad scientist could take the output from typeset -p, pipe that
    string and use it to create a new var downstream of the pipe!