X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=README;h=3d18dc28294f0f2dfe87062cd8ca4660b3cd2219;hb=d145782ea0dc424dae204d1be1d07eac51c87ccf;hp=0b84a0ec35dcfd6aec0c08736bd3f9b028b25b91;hpb=faea3b5420ab60445e8efb82940fac474a441de1;p=subdirmk.git

diff --git a/README b/README
index 0b84a0e..3d18dc2 100644
--- a/README
+++ b/README
@@ -174,10 +174,11 @@ So pathname syntax is a subset of:
 	by the final warning state after processing all the toplevel
 	input files (including Final.sd.mk).
 
-&:local+global [&]VARIABLE ...
-	Suppresses the warning about seeing both VARIABLE and
-	&VARIABLE.  Any & specified in the RHS is redundant: this
-	always affects both versions identically.
+&:local+global [!][&]VARIABLE ...
+	Suppresses any warnings relating to forthcoming mentions
+	to VARIABLE or &VARIABLE, as applicable.  Scope ends at
+	the end of the current directory's Suffix.sd.mk.
+	Prefixing with ! removes [&]VARIABLE from the suppresion list.
 
 &:changequote NEWQUOTE
 	changes the escape sequence from & to literally NEWQUOTE
@@ -205,6 +206,10 @@ Dollar doubling and macro assistance
 &$-		Stops dollar-doubling
 	Both are idempotent and local to the file or context.
 
+This is useful both for make macrology involving $(eval ...), and
+possibly for helping write complicated recipes involving shell
+variables, inline Perl code, etc.
+
 Sometimes we will show $'s being doubled inside another construct.
 This means the content of the construct is $-doubled: $-doubling is
 locally enabled, and restored afterwards.
@@ -233,8 +238,8 @@ $	=>	$$	including $'s produced by other
 			 &-expansions not mentioned here
 
 &\$	=>	$
-&$(	=>	$(
-&$NN	=>	$(NN)	where N are digits
+&$(	=>	${	(expands to { } so it is useable for shell too)
+&$NN	=>	${NN}	where N are digits
 
 A few contexts do not support $-doubling, such as directive arguments
 or places where this might imply $-quadrupling.  (There is no way to
@@ -407,7 +412,7 @@ 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
+can sometimes find that `make' complains that one of your Dir.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