X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?p=subdirmk.git;a=blobdiff_plain;f=README;h=4da40911ce83909e880874de657b6d4db797992b;hp=bbec51884700b9776f8f9491f1b6375b0a9c1e0d;hb=8c6b02849c6918f1deac8e463b24335844d65b86;hpb=83e89d6960a536ab393aaf081cf9209a32508045

diff --git a/README b/README
index bbec518..4da4091 100644
--- a/README
+++ b/README
@@ -183,7 +183,7 @@ In more detail, with all the various options laid out:
              for      build     source       build         source
                                                        
   This       lc       &file     &^file       $(PWD)/&file  $(abs_src)/&file
-  directory  any      &/file    &^/file      $(PWD)/&file  $(abs_src)/&/file
+  directory  any      &/file    &^/file      $(PWD)/&/file $(abs_src)/&/file
              several  & f g h   &^ f g h     $(addprefix...)
                                              
   Top        lc       file      &~file
@@ -218,30 +218,38 @@ empty string).
 	The assumption is that filenames are usually lowercase and
 	variables usually uppercase.  Otherwise, use another syntax:
 
+&/		=>	sub/dir/			or nothing
 &_		=>	sub_dir_			or TOP_
-&=_		=>	sub_dir				or TOP
+&.		=>	sub/dir				or .
+	(This implies that `&./' works roughly like `&/', although
+	it can produce a needless `./')
 
-&/		=>	sub/dir/			or nothing
-&=/		=>	sub/dir				or .
+&=		=>	sub_dir				or TOP
 
 &^lc		=>	$(top_srcdir)/sub/dir/lc
 &^/		=>	$(top_srcdir)/sub/dir/
+&^.		=>	$(top_srcdir)/sub/dir
 
 &~lc		=>	$(top_srcdir)/lc
 &~/		=>	$(top_srcdir)/
+&~.		=>	$(top_srcdir)
 
 In general:
-    =	return subdir without delimiter (not allowed with `^' `~')
     ^   pathname of this subdirectory in source tree
     ~   pathname of top level of source tree
-    /	terminates the escape (needed if next is not lwsp or space)
+    /	terminates the path escape } needed if next is
+    _   terminates the var escape  } not lwsp or space)
+    .   terminates path escape giving dir name (excluding /)
+    =	terminates var escape giving only prefix part (rarely needed)
   lwsp  starts multi-word processing (see below)
 
 So pathname syntax is a subset of:
-    '&' [ '^' | '~' ] [ lc | '/' ]
+    '&' [ '^' | '~' ] [ lc | '/' | '.' | '=' ]
 
 &&		=>	&&		for convenience in shell runes
-\&		=>	&		general escaping mechanism
+
+&\&		=>	&		general escaping mechanism
+&\$		=>	$
 
 & thing thing... &
 &^ thing thing... &
@@ -266,21 +274,21 @@ So pathname syntax is a subset of:
 &#	delete everything to end of line
 	(useful if the RHS contains unrecognised & constructions)
 
-&!STUFF
-	changes the escape sequence from & to literally STUFF
-	STUFF may be any series of of non-whitespace characters,
-	and is terminated by EOL or lwsp.  &!STUFF and the lwsp
-	are discarded.
+&:changequote NEWQUOTE
+	changes the escape sequence from & to literally NEWQUOTE
+	NEWQUOTE may be any series of of non-whitespace characters,
+	and is terminated by EOL or lwsp.  The whole line is
+	discarded.
 
-	After this, write STUFF instead of &, everywhere.
+	After this, write NEWQUOTE instead of &, everywhere.
 	The effect is global and lasts until the next setting.
 	It takes effect on &:include'd files too, so maybe set
 	it back before using &:include.
 
 	Notably
-		STUFFSTUFF	=>	STUFFSTUFF
-		\STUFF		=>	STUFF
-		STUFF!&		set escape back to &
+		NEWQUOTENEWQUOTE	=> NEWQUOTENEWQUOTE
+		NEWQUOTE\NEWQUOTE	=> NEWQUOTE
+		NEWQUOTE:changequote &	set escape back to &
 
 &TARGETS_things
 	Handled specially.  If mentioned, declares that this
@@ -371,6 +379,13 @@ makefiles, you may find that just `make' is broken now and cannot get
 far enough to regenerate a working set of makefiles.  If this happens
 just rerun ./config.status by hand.
 
+If you go back and forth between different versions of your code you
+can sometimes find that `make' complains that one of your Subdir.sd.mk
+files is missing: typically, if iot was used and therefore a
+dependency in some other version of your code.  If you run `make
+clean' (or `make realclean') these dependencies are suppressed, which
+will clear up the problem.
+
 
 Legal information
 -----------------