Rewrite Makefile with directories as extra targets

Makefile

@@ -1,28 +1,60 @@
-LILY := ./build
+# Variables
+## Disables default SUFFIXES
+.SUFFIXES:
 
+## Define the command to compile .ly files
+### Currently set to a wrapper script around lilypond, presupplying options
+###+ ./build contains no-strip-output-dir, no-point-and-click, paper-size, preview
+LYFLAGS ?=
+LY = LYFLAGS=$(LYFLAGS) ./build
+
+## Auxiliary files that are not directly related to the source compilation
 AUX = README.md Makefile \
-	  build defs.ily \
-	  init-sets make-set \
-	  scores2json.py \
-	  tuneoverview shadowdir
-	  #.git .gitignore
+      build defs.ily \
+      init-sets make-set \
+      scores2json.py \
+      tuneoverview shadowdir
+      # .git .gitignore
 
+## Define the directories containing source files (.ly files)
 SRCDIRS := 2-4_marches 3-4_marches 4-4_marches 5-4_marches \
-		   6-8_marches 9-8_marches \
-		   standards template \
-		   airs hornpipes jigs reels strathspeys \
-		   other christmas sinterklaas suites
+           6-8_marches 9-8_marches \
+           standards template \
+           airs hornpipes jigs reels strathspeys \
+           other christmas sinterklaas suites
 
-LYSRCS := $(foreach dir,$(SRCDIRS),$(wildcard $(dir)/**/*.ly) $(wildcard $(dir)/*.ly))
-PDFOBJS = $(patsubst %.ly,%.pdf,$(LYSRCS))
+## Gather all .ly files in the defined source directories (recursive search)
+LYSRCS := $(foreach dir, $(SRCDIRS), \
+            $(wildcard $(dir)/**/*.ly) \
+            $(wildcard $(dir)/*.ly) \
+           )
 
+## Define the corresponding .pdf targets for each .ly source file
+PDFOBJS = $(patsubst %.ly, %.pdf, $(LYSRCS))
+
+#Targets
+## Default target: generate all PDF files from .ly files
 .PHONY: all
 all: $(PDFOBJS)
 
-# Pattern rules
-%.pdf %.preview.pdf %.preview.png &: %.ly
-	$(LILY) $<
-
+## Distribution target: Create a tarball containing source and auxiliary files
 .PHONY: dist
-dist: $(LYSRCS) $(PDFOBJS) $(AUX)
+dist: $(PDFOBJS) $(AUX)
 	@tar -zhvcf pipeband-music.tar.gz $(SRCDIRS) $(AUX)
+
+## Pattern rule for .ly to .pdf, .preview.pdf, and .preview.png compilation
+%.pdf : %.ly
+	$(LY) $<
+
+## Register individual pdf targets
+### This also allows for autocompletion
+$(PDFOBJS): %.pdf: %.ly
+
+## Handling subdirectories as targets
+SUBDIRS := $(addsuffix /,$(SRCDIRS)) $(foreach pdfobj, $(PDFOBJS), $(dir $(pdfobj)))
+### Sort and remove duplicates
+SUBDIRS := $(sort $(SUBDIRS))
+
+.PHONY: $(SUBDIRS)
+$(SUBDIRS) : % :
+	@$(MAKE) $(filter $(@D)/%.pdf,$(PDFOBJS))

build

@@ -23,4 +23,5 @@ BAGPIPELY="$LIB/bagpipe.ly/"
 OPTIONS="-dno-strip-output-dir -dno-point-and-click -dpaper-size=\"a4landscape\""
 
 # Execute
-lilypond -dinclude-settings=$STYLESHEET -I $LILYDRUM -I $BAGPIPELY $OPTIONS -dpreview "$@"
+LYFLAGS="-dpreview${LYFLAGS+ }${LYFLAGS}"
+lilypond -dinclude-settings=$STYLESHEET -I $LILYDRUM -I $BAGPIPELY $OPTIONS $LYFLAGS "$@"