Syntax: Introduce &. and friends

[subdirmk.git] / README

diff --git a/README b/README
index 3390adff9d4e8bca1098b7e88b7f959004a987be..67ce6cc17c8fd3755ecddf39a675a073850f11ff 100644 (file)
--- a/README
+++ b/README
@@ -218,27 +218,33 @@ 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
@@ -266,11 +272,11 @@ So pathname syntax is a subset of:
 &#     delete everything to end of line
        (useful if the RHS contains unrecognised & constructions)
 
-&!STUFF
+&:changequote 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.
+       and is terminated by EOL or lwsp.  The whole line is
+       discarded.
 
        After this, write STUFF instead of &, everywhere.
        The effect is global and lasts until the next setting.
@@ -278,9 +284,9 @@ So pathname syntax is a subset of:
        it back before using &:include.
 
        Notably
-               STUFFSTUFF      =>      STUFFSTUFF
-               \STUFF          =>      STUFF
-               STUFF!&         set escape back to &
+               STUFFSTUFF              => STUFFSTUFF
+               \STUFF                  => STUFF
+               STUFF:changequote &     => set escape back to &
 
 &TARGETS_things
        Handled specially.  If mentioned, declares that this