automatic regeneration for all of this template substitution, and for
config.status etc. is done for you.
-Summary of directory reference syntaxes
----------------------------------------
+Summary of recommended directory reference syntaxes
+---------------------------------------------------
- In source tree In build tree
- Relative Absolute Relative Absolute
+Path construction &-expansions, meanings summary:
- &file $(abs)/&file
- This directory &^/file &~/file &/file $(abs)/&/file
- & ^ f g h & ~ f g h & f g h
+ In build tree In source tree
+ This directory just & &,
+ Top level &. implies absolute &;
- Top level $(ts)/file $(ats)/file file $(abs)/file
- f g h
+Adding `@' means "absolute path". This is not needed with &. because
+there is never any need to use &. since it would expand to nothing.
+`/' terminates the escape (needed if the next thing is not a lowercase
+character, or space). `=' means "just the value, no /". Space starts
+multi-word processing.
+
+ Recommended In build tree In source tree
+ when Relative Absolute Relative Absolute
+
+ This lc &file &@file &,file &@,file
+ directory any &/file &@/file &,/file &@,/file
+ several & f g h &@ f g h &, f g h &@, f g h
+
+ Top lc &.file &;file &@;file
+ level any file &./file &;/file &@;/file
+ several f g h &. f g h &; f g h &@; f g h
+ .mk.in file $(abs)/file $(src)/file $(abs_src)/file
Substitution syntax
-------------------
variables usually uppercase. Otherwise, use another syntax:
&_ => sub_dir_ or TOP_
-&/ => sub/dir/ or nothing
&=_ => sub_dir or TOP
+
+&/ => sub/dir/ or nothing
&=/ => sub/dir or .
-&^ => $(top_srcdir)/sub/dir or $(top_srcdir)
-&~ => $(abs_top_srcdir)/sub/dir or $(abs_top_srcdir)
+
+&,lc => $(top_srcdir)/sub/dir/lc
+&,/ => $(top_srcdir)/sub/dir/
+
+&;lc => $(top_srcdir)/sub/dir/lc
+&;/ => $(top_srcdir)/sub/dir/
+
+&@lc => $(PWD)/sub/dir/lc
+&@/ => $(PWD)/sub/dir/
+
+&.lc => $(PWD)/lc
+&./ => $(PWD)/
+
+&@,lc => $(abs_top_srcdir)/sub/dir/lc
+&@,/ => $(abs_top_srcdir)/sub/dir/
+
+&@;lc => $(abs_top_srcdir)/sub/dir/lc
+&@;/ => $(abs_top_srcdir)/sub/dir/
+
+In general:
+ = return subdir without delimiter (not allowed with `,' `;' `@')
+ , pathname of this subdirectory in source tree
+ ; pathname of top level of source tree
+ . pathname of this directory in build tree, implies absolute pathnames
+ @ absolute pathnames (forbidden with `.', must come first)
+
+So pathname syntax is a subset of:
+ '&' [ '@' ] [ ',' | ';' | '.' ] [ lc | '/' ]
+
+ To avoid incomprehensible .sd.mk files, some combinations are not
+ allowed. For example `&@=./' would mean `$(PWD)/sub/dir' but can
+ be spelled `$(PWD)/&=/', but more normally the trailing / can be
+ tolerated, so use `&@/'.
&& => && for convenience in shell runes
\& => & general escaping mechanism
& thing thing... &
-& ^ thing thing... &
-& ~ thing thing... &
+&. thing thing... & &@. thing thing... &
+&, thing thing... & &@, thing thing... &
+&; thing thing... & &@; thing thing... &
Convenience syntax for prefixing multiple filenames.
- Introduced by & followed by lwsp (space or tab).
- Each lwsp-separated non-ws word is prefixed by &/ &^/ &~/
- respectively. No other & escapes are recognised.
+ Introduced by & followed by lwsp where lc could go.
+ Each lwsp-separated non-ws word is prefixed by &/ &./ &@./
+ etc. respectively. No other & escapes are recognised.
This processing continues until & preceded by lwsp,
or until EOL (the end of the line), or \ then EOL.