A Makefile to build SASS files with automatically generated dependencies from a target's imports.

Makefile

OUTPUT_DIR := build
SOURCES_DIR := styles
DEPS_DIR := .deps

RM := rm -rf
RUBY := ruby
SASS := scss
SASS_OPTIONS := --unix-newlines
SASS_OPTIONS += --style compressed
SASS_OPTIONS += --precision 8
SASS_OPTIONS += -E utf-8
SASS_OPTIONS += --no-cache
SASS_DEPENDENCY_GENERATOR := $(RUBY)
SASS_DEPENDENCY_GENERATOR += -r sass
SASS_DEPENDENCY_GENERATOR += -e
SASS_DEPENDENCY_GENERATOR += 'deps = Sass::Engine.for_file(ARGV[0], {cache: false}).dependencies.collect { |d| d.options[:filename] };\
File.open("$(DEPS_DIR)/" + File.basename(ARGV[0]) + ".d", "w") { |f| f.puts ARGV[1] + ": " + deps.join(" "); f.puts "\n" + deps.join(":\n\n") + ":" unless deps.empty? }'

QUIET_RUBY = @echo RUBY '' $(notdir $<).d;
QUIET_SASS = @echo SASS '' $(notdir $@);

SOURCES := $(shell ls $(SOURCES_DIR)/[^_]*.scss)
TARGETS := $(addprefix $(OUTPUT_DIR)/,$(SOURCES:.scss=.css))
D_FILES := $(addprefix $(DEPS_DIR)/,$(addsuffix .d,$(subst $(SOURCES_DIR)/,,$(SOURCES))))


all: $(TARGETS)

$(OUTPUT_DIR)/$(SOURCES_DIR)/%.css: $(SOURCES_DIR)/%.scss
	$(QUIET_RUBY)$(SASS_DEPENDENCY_GENERATOR) $< $@
	$(QUIET_SASS)$(SASS) $(SASS_OPTIONS) $< $@
-include $(D_FILES)

clean:
	$(RM) $(TARGETS) $(DEPS_DIR)

.PHONY: all clean