Syntax: Expand &$( and &$NN to use ${ } rather than $( )

[subdirmk.git] / README

diff --git a/README b/README
index 0b84a0ec35dcfd6aec0c08736bd3f9b028b25b91..14cc5420f4783f5f4568c73e58eab1c48f5759f9 100644 (file)
--- a/README
+++ b/README
@@ -205,6 +205,10 @@ 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 +237,8 @@ $   =>      $$      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