Makefile find in array

If I have something like this:

PROJECTS += path/to/first
PROJECTS += path/to/second
PROJECTS += path/to/third

and

LIBS += lib_output/first.lib
LIBS += lib_output/second.lib
LIBS += lib_output/third.lib

How could I associate the project from PROJECTS += path/to/first with LIBS += lib_output开发者_开发百科/first.lib? Is there something like a hashmap available in a makefile? Or possibility to search in an array?

You can simulate lookup tables using computed variable names and the fact that make variable names can include some special characters like dot and forward slash:

PROJECTS += path/to/first
PROJECTS += path/to/second
PROJECTS += path/to/third

LIBS += lib_output/first.lib
LIBS += lib_output/second.lib
LIBS += lib_output/third.lib

lookup.path/to/first  := lib_output/first.lib
lookup.path/to/second := lib_output/second.lib
lookup.path/to/third  := lib_output/third.lib

path := path/to/first
$(info ${path} -> ${lookup.${path}})
path := path/to/second
$(info ${path} -> ${lookup.${path}})
path := path/to/third
$(info ${path} -> ${lookup.${path}})

Outputs:

$ make
path/to/first -> lib_output/first.lib
path/to/second -> lib_output/second.lib
path/to/third -> lib_output/third.lib

I'm not sure if I completely understand your question, but I think the word function might be what you need (it may be a GNU make extension):

$(word 2, $(PROJECTS)) returns path/to/second,
$(word 2, $(LIBS)) returns lib_output/second.lib.