Added nanobind_setup_libname helper function

[vfdev-5]

Context: #844 (reply in thread)

cc @wjakob

[wjakob]

How about giving this function the same signature as nanobind_add_module? Then the arguments can easily be forwarded, which I think is convenient. Let's call it nanobind_libname

[vfdev-5]

How about giving this function the same signature as nanobind_add_module? Then the arguments can easily be forwarded, which I think is convenient. Let's call it nanobind_libname

nanobind_add_module signature is just name and all other arguments are parsed with cmake_parse_arguments.
I'm not totally sure how can we forward the arguments ("STABLE_ABI;FREE_THREADED;NB_STATIC;NB_SHARED;PROTECT_STACK;LTO;NOMINSIZE;NOSTRIP;MUSL_DYNAMIC_LIBCPP") which could be parsed first by nanobind_add_module and then also by nanobind_libname.

Also parsed arguments like ARG_STABLE_ABI, ARG_NB_STATIC etc are then set to some default value depending on their mutual values:

nanobind/cmake/nanobind-config.cmake

Lines 322 to 339 in 8badd40

	if (ARG_NB_SHARED AND ARG_NB_STATIC)
	message(FATAL_ERROR "NB_SHARED and NB_STATIC cannot be specified at the same time!")
	elseif (NOT ARG_NB_SHARED)
	set(ARG_NB_STATIC TRUE)
	endif()
	# Stable ABI builds require CPython >= 3.12 and Python::SABIModule
	if ((Python_VERSION VERSION_LESS 3.12) OR
	(NOT Python_INTERPRETER_ID STREQUAL "Python") OR
	(NOT TARGET Python::SABIModule))
	set(ARG_STABLE_ABI FALSE)
	endif()
	if (NB_ABI MATCHES "t")
	set(ARG_STABLE_ABI FALSE)
	else(ARG_STABLE_ABI)
	set(ARG_FREE_THREADED FALSE)
	endif()

If you have few more details on the idea how to move forward I'm all ears.

EDIT: we can otherwise do this for a bit more simple args forwarding:

function (f2 name)
    cmake_parse_arguments(PARSE_ARGV 1 ARG2 "A;B;C" "" "")

    message("2 - A: ${ARG2_A}")
    message("2 - B: ${ARG2_B}")
    message("2 - C: ${ARG2_C}")
endfunction()


function (f1 name)
    cmake_parse_arguments(PARSE_ARGV 1 ARG1 "A;B;C" "" "")

    message("1 - A: ${ARG1_A}")
    message("1 - B: ${ARG1_B}")
    message("1 - C: ${ARG1_C}")

    set(args ${name})
    if (ARG1_A)
        list(APPEND args A)
    endif()
    if (ARG1_B)
        list(APPEND args B)
    endif()
    if (ARG1_C)
        list(APPEND args C)
    endif()

    f2(${args})

endfunction()


f1("test" A B)
f2("t2" A C)

Output:

1 - A: TRUE
1 - B: TRUE
1 - C: FALSE
2 - A: TRUE
2 - B: TRUE
2 - C: FALSE
2 - A: TRUE
2 - B: FALSE
2 - C: TRUE