Macro assistance part 1 - macro directive

[subdirmk.git] / README

diff --git a/README b/README
index 7de4def345f95bdfa39f6da34992be894b22e11f..130a1c7fbfc085dc9d2b5b8cf65a7d1b7f9c506b 100644 (file)
--- a/README
+++ b/README
@@ -254,7 +254,7 @@ So pathname syntax is a subset of:
 &&             =>      &&              for convenience in shell runes
 
 &\&            =>      &               general escaping mechanism
-&\$            =>      $
+&\$            =>      $               provided for $-doubling regimes
 &\NEWLINE                              eats the newline and vanishes
 
 &$VARIABLE     =>      $(sub_dir_VARIABLE)     or $(TOP_VARIABLE)
@@ -323,6 +323,34 @@ So pathname syntax is a subset of:
        `all' is extra special: every directory has an `all'
        target, which corresponds to &TARGETS.
 
+
+Dollar doubling and macro assistance
+------------------------------------
+
+&$+            Starts dollar-doubling
+&$-            Stops dollar-doubling
+       Both are idempotent and local to the file or context.
+
+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.
+
+&:macro NAME   =>      define NAME
+STUFF $ THINGS ..      STUFF $$ THINGS
+&:endm         ..      endef
+       NAME is processed for &
+
+While dollar-doubling:
+- - - - - - - - - - -
+
+$      =>      $$      including $'s produced by other
+                        &-expansions not mentioned here
+
+&\$    =>      $
+&$NN   =>      $(NN)   where N are digits
+&$(    =>      $(
+
+
 Subdirectory and variable naming
 --------------------------------