Config Manager: Makefile

HOSTNAME   := $(shell hostname)
BUILD      := $(patsubst %.d,build/%,$(wildcard *.d))
BUILD_DEST := $(patsubst %.d,%,$(wildcard *.d))
ASIS       := $(filter-out Makefile build tools %.d,$(wildcard *))
INSTALL    := $(addprefix ~/.,$(subst \#,/,$(BUILD_DEST) $(ASIS)))

FORCE      := a # available: y=yes, always; n=no, never; a=ask

COMBINE    := tools/combine-config
ISL        := tools/install-symlink

all: $(BUILD)

clean:
    @echo "You probably don't want to actually do a 'make clean' as the"
    @echo "symlinks in your home directory can point to files in build/"
    @echo
    @echo "If you really want to, just rm -Rf build/"
    @exit 1

install: $(INSTALL)

.DELETE_ON_ERROR:
.SECONDARY:
.PHONY: all clean install

~/.%: %
    $(ISL) $(FORCE) "$<" "$@"
~/.%: build/%
    $(ISL) $(FORCE) "$<" "$@"

.SECONDEXPANSION:

# Note that patsubst does not seem to work in second expansion. Its
# documented to, but doesn't, at least with Debian GNU make 3.81-8.3.
build/%: %.d $(COMBINE) $$(wildcard $$(addsuffix .d,$$(subst build/,,$$<))/*)
    @mkdir -p build
    if [ -e "$@" ]; then chmod u+w "$@"; fi
    $(COMBINE) "$(HOSTNAME)" $(wordlist 3,66535,$+) > "$@"
    chmod u-w "$@"

~/.%: build/$$(subst /,\#,$$(subst $(HOME)/.,,$$@))
    mkdir -p $(dir $@)
    $(ISL) $(FORCE) "$<" "$@"

~/.%: $$(subst /,\#,$$(subst $(HOME)/.,,$$@))
    mkdir -p $(dir $@)
    $(ISL) $(FORCE) "$<" "$@"