Rewritten rule details; only execute rule when SUBPROJECTS is not empty;

added verbose commenting


git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/tools/make/trunk@14797 72102866-910b-0410-8b05-ffd578937521

Master/aggregate.make

@@ -3,10 +3,11 @@
 #
 #   Master Makefile rules to build a set of GNUstep-base subprojects.
 #
-#   Copyright (C) 1997 Free Software Foundation, Inc.
+#   Copyright (C) 1997-2002 Free Software Foundation, Inc.
 #
 #   Author:  Scott Christley <scottc@net-community.com>
 #   Author:  Ovidiu Predescu <ovidiu@net-community.com>
+#   Author:  Nicola Pero <n.pero@mi.flashnet.it>
 #
 #   This file is part of the GNUstep Makefile Package.
 #
@@ -25,33 +26,48 @@ include $(GNUSTEP_MAKEFILES)/rules.make
 endif
 
 #
-# The list of directory names with the subprojects is in the makefile 
-# variable SUBPROJECTS
+# The list of aggregate project directory names is in the makefile
+# variable SUBPROJECTS.  The name is unforunate, because it is confusingly
+# similar to xxx_SUBPROJECTS, which is used for subprojects.
 #
+# SUBPROJECTS - which is implemented in this file - are just a list of
+# directories; we step in each directory in turn, and run a submake in
+# there.  The project types in the directories can be anything -
+# tools, documentation, libraries, bundles, applications, whatever.
+# For example, if your package is composed by a library and then by
+# some tools using the library, you could have the library in one
+# directory, the tools in another directory, and have a top level
+# GNUmakefile which has the two as SUBPROJECTS.
+#
+# xxx_SUBPROJECTS - which is *not* implemented in this file, I'm just
+# explaining it here to make clear the difference - are again a list
+# of directories, each of which should contain a *subproject* project
+# type (as implemented by subproject.make), which builds stuff into a
+# .o file, which is then automatically linked into the xxx instance by
+# gnustep-make when the top-level xxx is built.  For example, a
+# library might be broken into many separate subprojects, each of
+# which implementing a logically separated part of the library; the
+# top-level GNUmakefile will then build the library, specifying
+# xxx_SUBPROJECTS for the library to be those directories.
+# gnustep-make will step in all dirs, compile the subprojects, and
+# then finally automatically link the subprojects into the main
+# library.
 SUBPROJECTS := $(strip $(SUBPROJECTS))
 
-#
-# Internal targets
-#
+ifneq ($(SUBPROJECTS),)
 internal-all internal-install internal-uninstall internal-clean \
   internal-distclean internal-check::
-	@ target=$(subst internal-,,$@); \
-	for f in $(SUBPROJECTS) __done; do \
-	  if [ $$f != __done ]; then       \
-	    echo Making $$target in $$f...; \
-	    mf=$(MAKEFILE_NAME); \
-	    if [ ! -f "$$f/$$mf" -a -f "$$f/Makefile" ]; then \
-	      mf=Makefile; \
-	      echo "WARNING: No $(MAKEFILE_NAME) found for subproject $$f; using 'Makefile'"; \
-	    fi; \
-	    if $(MAKE) -C $$f -f $$mf --no-keep-going \
-		GNUSTEP_INSTALLATION_DIR="$(GNUSTEP_INSTALLATION_DIR)" \
-	        $$target; then \
-	      :; else exit $$?; \
-	    fi; \
+	@ operation=$(subst internal-,,$@); \
+	for f in $(SUBPROJECTS); do \
+	  echo "Making $$operation in $$f..."; \
+	  mf=$(MAKEFILE_NAME); \
+	  if [ ! -f "$$f/$$mf" -a -f "$$f/Makefile" ]; then \
+	    mf=Makefile; \
+	    echo "WARNING: No $(MAKEFILE_NAME) found for aggregate project $$f; using 'Makefile'"; \
+	  fi; \
+	  if $(MAKE) -C $$f -f $$mf --no-keep-going $$operation; then \
+	    :; else exit $$?; \
 	  fi; \
 	done
+endif
 
-## Local variables:
-## mode: makefile
-## End: