# NB: don"t use ANY quotes ('/") for put()/add()/set() arguments!
# shell will get confused by ' or args get spammed with "

# pay attention to the context in which functions get called:
# e.g. features.in/syslinux/config.mk introduces conditionals

# this one adds whatever is given as an argument
put = $(and $(1),$(put_body))
define put_body
{ $(log_body); \
printf '%s\n' '$(1)' >> "$(CONFIG)"; }
endef

# these two take two args
# add() just appends an additive rule...
add = $(and $(1),$(2),$(add_body))
define add_body
{ $(log_body); \
printf '%s += %s\n' '$(1)' '$(2)' >> "$(CONFIG)"; }
endef

# ...set() comments out any previous definition
# and then appends an assigning rule
set = $(and $(1),$(2),$(set_body))
define set_body
{ $(log_body); \
subst 's|^$(1)[ 	]*+*=.*$$|#& # overridden by $@|' "$(CONFIG)"; \
printf '%s = %s\n' '$(1)' '$(2)' >> "$(CONFIG)"; }
endef

# is there a way to set a global make var from a recipe?..
define log_body
{ grep -q '^# $@$$' "$(CONFIG)" || printf '# %s\n' '$@' >> "$(CONFIG)"; }
endef

tags = $(shell echo "$(1)" | bin/tags2lists)