# http://stackoverflow.com/a/18137056/377022
Makefile_coq_compat_84_85_ocaml_mkfile_path := $(lastword $(MAKEFILE_LIST))
Makefile_coq_compat_84_85_ocaml_mkfile_abspath := $(abspath $(Makefile_coq_compat_84_85_ocaml_mkfile_path))
Makefile_coq_compat_84_85_ocaml_mkfile_dir := $(patsubst %/,%,$(dir $(Makefile_coq_compat_84_85_ocaml_mkfile_path)))
Makefile_coq_compat_84_85_ocaml_mkfile_absdir := $(patsubst %/,%,$(dir $(Makefile_coq_compat_84_85_ocaml_mkfile_abspath)))
Makefile_coq_compat_84_85_ocaml_current_dir := $(notdir $(Makefile_coq_compat_84_85_ocaml_mkfile_dir))
Makefile_coq_compat_84_85_ocaml_current_absdir := $(notdir $(Makefile_coq_compat_84_85_ocaml_mkfile_absdir))

.PHONY: update-ml-files

FAST_TARGETS += update-ml-files
SUPER_FAST_TARGETS += update-ml-files

TEST_EXISTS_ML_FUNCTION_OUTPUT=/dev/null
test_exists_ml_function = $(strip $(shell FUNCTION="$1" COQBIN="$(COQBIN)" $(Makefile_coq_compat_84_85_ocaml_mkfile_dir)/test-exists-ml-function.sh >$(TEST_EXISTS_ML_FUNCTION_OUTPUT) 2>$(TEST_EXISTS_ML_FUNCTION_OUTPUT); echo $$?))

update-ml-files:: FORCE
	@ echo "## "
	@ echo '## Switching to OCaml files for $(ML_DESCRIPTION).'
	@ echo "## "

define SET_ML_COMPATIBILITY
# $(1) - path to base ml file
# $(2) - expected extension

ifeq ($(filter $(1), $(ML_COMPATIBILITY_FILES)),)
FORCE::
	@ echo
	@ echo "\033[0;31mERROR: $(1) is missing from ML_COMPATIBILITY_FILES\033[0m"; \
	echo "\033[0;31mThis causes creation of .ml*.d files to fail, as it\033[0m"; \
	echo "\033[0;31mhappens too early.\033[0m"; \
	echo "\033[0;31mThe value of ML_COMPATIBILITY_FILES is '$(ML_COMPATIBILITY_FILES)'\033[0m"
	@ echo
	@ false
endif

ifneq ($(call test_files_are_same,$(1),$(1)$(2)),0)
$(1): update-ml-files

update-ml-files::
	$(SHOW)'CP $(1)$(2)'
	$(HIDE)cp -f "$(1)$(2)" "$(1)"
	$(HIDE)touch "$(1)"
endif
endef