automatic regeneration for all of this template substitution, and for
config.status etc. is done for you.
-Summary of directory reference syntaxes
----------------------------------------
-
- In build tree In source tree
- Relative Absolute Relative Absolute
-
- &file $(abs)/&file
- This directory &/file $(abs)/&/file &^/file &~/file
- & f g h & ^ f g h & ~ f g h
-
- Top level file $(abs)/file $(ts)/file $(ats)/file
- f g h
+Summary of recommended directory reference syntaxes
+---------------------------------------------------
+
+Path construction &-expansions, meanings summary:
+
+ Relative paths in... Absolute paths in...
+ build source build source
+
+ This directory & &, &@ &@,
+ Top level . &; &@. &@;
+
+Adding `@' means "absolute path". (`&.' is not allowed without @
+because just `&./' is a silly way of writing `.'.) `/' 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.
+
+In more detail, with the various options for what comes next:
+
+ Recommended Relative paths in... Absolute paths in...
+ for build source build source
+
+ 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 &@;file
+ level any file &;/file &@./file &@;/file
+ several f g h &; f g h &@. f g h &@; f g h
+ .mk.in file $(src)/file $(abs)/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)/lc &;/ => $(top_srcdir)/
+
+&@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)/lc &@;/ => $(abs_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
+ . pathname of this directory in build tree, `@' must be specified
+ @ absolute pathnames
+
+So pathname syntax is a subset of:
+ '&' [ '@' ] [ ',' | ';' | '.' ] [ lc | '/' ]
+
+ To avoid incomprehensible .sd.mk files, some combinations are not
+ allowed. For example `&=./' would mean `.' and `&./' would be the
+ empty string. Variations with `=' and one of `@' `,' `;' are
+ uncommon and must be written using make variables instead.
&& => && 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... & &@; 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.
+ 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.
~ian / subdirmk.git / blobdiff