Re: Creating a unique list from a bunch of duplicates

[Christoph Schulz]

Hello!

> Hi,
>
>   I need to be able to take a list of directories and remove the 
> duplicates without sorting the list.  For example, if I have "-L/abc/lib 
> -L/def/lib -L/abc/lib" I would like to get back "-L/abc/lib 
> -L/def/lib".  I would like to do this within make so that I don't have 
> to call a bunch of shell functions.  I've talked to a number of other 
> gmake makefile writers and they agree that this would be very helpful.  
> Is there such a function in make?  (Like $(unique list) or some such?)  
> If not, has someone well versed in functional programming put together a 
> bunch of filter/foreach/search/etc functions to do this?  Any help on 
> this would be greatly appreciated.  Also, if you know of a better 
> location to send this request to, please let me know.


# Removes duplicates in a list of words without changing order.
# $(1) = list of words
# (put everything below into one line!)
devRemoveDuplicates = $(if $(1),$(strip $(word 1,$(1)) $(call
devRemoveDuplicates,$(filter-out $(word 1,$(1)),$(1)))))

It works with make 3.80 and newer.

HTH,
  Christoph