Simplest way to reverse the order of strings in a make variable

Question

Let\'s say you have a variable in a makefile fragment like the following:

MY_LIST=a b c d

How do I then reverse the order of that list? I need

Answer 1

Playing off of both Ben Collins' and elmarco's answers, here's a punt to bash which handles whitespace "properly"¹

reverse = $(shell printf "%s\n" $(strip $1) | tac)

which does the right thing, thanks to $(shell) automatically cleaning whitespace and printf automatically formatting each word in its arg list:

$(info [ $(call reverse,  one two   three four  ) ] )

yields:

[ four three two one ]

¹...according to my limited test case (i.e., the $(info ...) line, above).