func to remove dupes

[Stephan Beal]

Hi, all!

i've created a function which removes duplicates from a list while 
keeping their relative order untouched (code is below). While it 
appears to work fine, i'm not at all happy with the temp var it uses 
($(remove-dupes-holder)). Is there anyone out there who would care to 
take a crack at improving this function, so that it doesn't need the 
extra variable (or any improvement, for that matter)?

####################################################
# $(call remove-dupes,list)
# Returns a string equal to list with duplicate entries
# removed. It does not sort the list.
remove-dupes-holder :=
remove-dupes-impl = $(if $(filter $(1),$(remove-dupes-holder)),,\
                        $(eval remove-dupes-holder+=$1))
remove-dupes = $(strip \
        $(eval remove-dupes-holder:=)\
        $(foreach ENTRY,\
                $(if $1,$1,),\
                $(call remove-dupes-impl,$(ENTRY)))\
        $(remove-dupes-holder))

##################################
# Test code:
ifeq (1,1)
remove-dupes-test:
        # remove-dupes: $(call remove-dupes,c b a a b c)
        # remove-dupes: <$(call remove-dupes,a b A a b B c a c c b d C)>
        # remove-dupes: <$(call remove-dupes,$(strip ))>
#       # remove-dupes: <$(call remove-dupes)>
else
all:
endif


$ make -f remove-dupes.make
# remove-dupes: c b a
# remove-dupes: <a b A B c d C>
# remove-dupes: <>




-- 
----- stephan beal
http://www.wanderinghorse.net

signature.asc
Description: This is a digitally signed message part.