X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?p=subdirmk.git;a=blobdiff_plain;f=README;h=e3259c0924414e19770c5fa42007646696ddbdab;hp=c9e4c0f9234f2fe42bac8187dd98c88784bb417a;hb=033421585dfa781211b558d7acc310b8540ba60e;hpb=0a6ac67828982aca4e3c8ac73669420a30c70f34 diff --git a/README b/README index c9e4c0f..e3259c0 100644 --- a/README +++ b/README @@ -90,20 +90,34 @@ Unlike `all', these other targets only exist in areas of the project where at least something mentions them. So for example, if &TARGETS_zonk is mentioned in src but not lib, `make zonk' in lib will fail. If you want to make a target exist everywhere, -mention its name in Perdir.sd.mk (see below). +mention its name in Prefix.sd.mk or Suffix.sd.mk (see below). -Perdir.sd.mk, inclusion ------------------------ +Prefix.sd.mk, Suffix.sd.mk, inclusion +------------------------------------- -The file Perdir.sd.mk in the toplevel of the source is automatically -processed after each individual directory's Subdir.sd.mk, and the -&-substituted contents therefore appear once for each subdirectory. +The files Prefix.sd.mk and Suffix.sd.mk in the toplevel of the source +are automatically processed before and after each individual +directory's Subdir.sd.mk, and the &-substituted contents therefore +appear once for each subdirectory. This lets you do per-directory boilerplate. Some useful boilerplate is already provided in subdirmk, for you to reference like this: &:include subdirmk/cdeps.sd.mk &:include subdirmk/clean.sd.mk -For example you could put that in Perdir.sd.mk. +For example you could put that in Suffix.sd.mk. + +The top-level Subdir.sd.mk is the first makefile included after the +autogenerated `main.mk' which merely has some basic settings and +includes. So if you want to get in early and set global variables, +put them near the top of Subdir.sd.mk. + +subdirmk's filter script itself sets (only) these variables: + top_srcdir + abs_top_srcdir + SUBDIRMK_MAKEFILES + MAKEFILE_TEMPLATES +You are likely to want to define $(PWD), and shorter names for +top_srdir and abs_top_srcdir (we suggest $(src) and $(abs_src)). Global definitions ------------------ @@ -134,7 +148,7 @@ There are two kinds of template files. How to include `&:include foo.sd.mk' `include foo.mk' in all relevant .sd.mk in only one (but not needed for Subdir.sd.mk - Subdir and Perdir) + Prefix, Suffix) If you `include subdirmk/regen.mk', dependency management and automatic regeneration for all of this template substitution, and for @@ -161,22 +175,22 @@ Path construction &-expansions are built from the following: Relative paths in... build source - This directory & &, - Top level . &; + This directory & &^ + Top level . &~ In more detail, with all the various options laid out: Recommended Relative paths in... Absolute paths in... for build source build source - This lc &file &,file $(PWD)/&file $(abs_src)/&file - directory any &/file &,/file $(PWD)&/file $(abs_src)/&/file - several & f g h &, f g h $(addprefix...) + This lc &file &^file $(PWD)/&file $(abs_src)/&file + directory any &/file &^/file $(PWD)/&/file $(abs_src)/&/file + several & f g h &^ f g h $(addprefix...) - Top lc file &;file - level any file &;/file $(PWD)/file $(abs_src)/file + Top lc file &~file + level any file &~/file $(PWD)/file $(abs_src)/file .mk.in file $(src)/file $(PWD)/file $(abs_src)/file - several f g h &; f g h $(addprefix...) + several f g h &~ f g h $(addprefix...) (This assumes you have appropriate make variables src, PWD and abs_src.) @@ -205,34 +219,46 @@ 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/ +&^lc => $(top_srcdir)/sub/dir/lc +&^/ => $(top_srcdir)/sub/dir/ +&^. => $(top_srcdir)/sub/dir -&;lc => $(top_srcdir)/lc -&;/ => $(top_srcdir)/ +&~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) + ^ pathname of this subdirectory in source tree + ~ pathname of top level of source tree + / 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 + +&\& => & general escaping mechanism +&\$ => $ +&\NEWLINE eats the newline and vanishes + +&$VARIABLE => $(sub_dir_VARIABLE) or $(TOP_VARIABLE) + VARIABLE is ASCII starting with a letter and matching \w+ & thing thing... & -&, thing thing... & -&; thing thing... & +&^ thing thing... & +&~ thing thing... & Convenience syntax for prefixing multiple filenames. Introduced by & followed by lwsp where lc could go. Each lwsp-separated non-ws word is prefixed by &/ etc. @@ -242,35 +268,37 @@ So pathname syntax is a subset of: &: .... recognised at start of line only (possibly after lwsp) - args are processed for & -&:include filename filename should usually be foo.sd.mk +&:include filename filename should usually be [&]foo.sd.mk &:-include filename tolerate nonexistent file filenames are relative to $(top_srcdir) + RHS is &-expanded &! disables & until EOL (and then disappears) &# delete everything to end of line (useful if the RHS contains unrecognised & constructions) -&!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. +&:changequote NEWQUOTE + changes the escape sequence from & to literally NEWQUOTE + NEWQUOTE may be any series of of non-whitespace characters, + and is terminated by EOL or lwsp. The whole line is + discarded. - After this, write STUFF instead of &, everywhere. + After this, write NEWQUOTE instead of &, everywhere. The effect is global and lasts until the next setting. It takes effect on &:include'd files too, so maybe set it back before using &:include. Notably - STUFFSTUFF => STUFFSTUFF - \STUFF => STUFF - STUFF!& set escape back to & + NEWQUOTENEWQUOTE => NEWQUOTENEWQUOTE + NEWQUOTE\NEWQUOTE => NEWQUOTE + NEWQUOTE\$ => $ + NEWQUOTE:changequote & set escape back to & &TARGETS_things - Handled specially. If mentioned, declares that this + Handled specially. If mentioned at the start of a line + (possibly following whitespace), declares that this subdir ought to have a target `things'. The rule will be &/things:: $(&TARGETS_things) @@ -284,9 +312,9 @@ So pathname syntax is a subset of: which recursively implies this directory's `things'. Must be spelled exactly &TARGETS_things. &_TARGETS_things, - for example, is not magic. But mentioning &TARGETS_things in - a #-comment *does* work because the & filter does not care - about comments. + for example, is not magic. To make the target exist + without providing any prerequisites for it, write a line + containing just `&TARGETS_things +='. `all' is extra special: every directory has an `all' target, which corresponds to &TARGETS. @@ -327,7 +355,7 @@ probably contain: include subdirmk/usual.mk include subdirmk/regen.mk -Write a Perdir.sd.mk in the toplevel, if you want. It should probably +Write a Suffix.sd.mk in the toplevel, if you want. It should probably have: &:include subdirmk/cdeps.sd.mk @@ -358,6 +386,13 @@ makefiles, you may find that just `make' is broken now and cannot get far enough to regenerate a working set of makefiles. If this happens just rerun ./config.status by hand. +If you go back and forth between different versions of your code you +can sometimes find that `make' complains that one of your Subdir.sd.mk +files is missing: typically, if iot was used and therefore a +dependency in some other version of your code. If you run `make +clean' (or `make realclean') these dependencies are suppressed, which +will clear up the problem. + Legal information -----------------