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undual

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  1. #!/bin/zsh
  2. #
  3. # undual - remove a name from the dual list
  4. #
  5. # [2000-09-29]
  6. # Version 3.1.6 of zsh automates this functionality with
  7. # typeset -T. I'll leave this function here for historical purposes.
  8. #
  9. # Usage:
  10. # undual [name] . . .
  11. #
  12. # where
  13. # name is the name of a shell variable to remove from the
  14. # dual list. See dual for more. You can't remove
  15. # dual itself from the dual list, which is kind of
  16. # good.
  17. #
  18. # assumes unsetopt shwordsplit
  19. # Might require a POSIX sed, on account of the
  20. # \(:\|$\) (colon or end of line) construct. In awk it becomes
  21. # (:|$) which is much easier to read. I use sed because it's a little
  22. # less memory-hungry.
  23. #
  25. # each name . . .
  26. for name
  27. do
  28. # get uppercase version
  29. upper=${(U)name}
  30. # if there is no dual list, quit now.
  31. if [[ -z "$dual" || -z "$DUAL" ]]
  32. then
  33. break
  34. fi
  35. # remove the item from the dual list - with dual!
  36. dual DUAL=$(echo $DUAL | sed "s/:$upper\(:\|$\)/\1/")
  37. # and remap the dual array to lower case.
  38. dual=(${(L)dual})
  39. done