generate: Make @nest always be nonempty

[subdirmk.git] / README

diff --git a/README b/README
index 130a1c7fbfc085dc9d2b5b8cf65a7d1b7f9c506b..20658ae2adc3087e1f24db87cababc19aaa154b9 100644 (file)
--- a/README
+++ b/README
@@ -340,6 +340,19 @@ STUFF $ THINGS     ..      STUFF $$ THINGS
 &:endm         ..      endef
        NAME is processed for &
 
+&${..$..} =>   ${eval ${call ..$$..}}
+       (matches { } pairs to find the end)
+       content is $-doubled (unless it contains $- to turn that off)
+
+       Together &:macro and &${...} provide a more reasonable macro
+       facility than raw make.  They solve the problem that make
+       expansions cannot directly generate multiple rules, variable,
+       etc.; instead, `$(eval )' must be used, but that re-expands
+       the argument, meaning that all the literal text must be
+       $-doubled.  This applies to the macro text and to the
+       arguments.  Also `$(eval $(call ...))' is an unfortunate syntax.
+       Hence &:macro and &${...}.
+
 While dollar-doubling:
 - - - - - - - - - - -