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
+^^^ rarely needed. TBD, maybe one of
+ &._ &_. &\_ &% &$_
+ &<varnameprefix> &[varnameprefix]
+ $(patsubst %_,&_,%)
&^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