X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?p=subdirmk.git;a=blobdiff_plain;f=README;h=20658ae2adc3087e1f24db87cababc19aaa154b9;hp=518dd087d853308b13e07aab805349714288d26e;hb=20e5ccd063565c2207066d4ed3b48be49143194b;hpb=d817b49007e60b0e7392f23caf08dc0328eb32de diff --git a/README b/README index 518dd08..20658ae 100644 --- a/README +++ b/README @@ -83,33 +83,38 @@ targets may be in run in parallel: there is only one `make' invocation at a time. There is no sequencing between subdirectories, only been individual targets (as specified according to their dependencies). -You can define other per-directory recursive targets too: simply -mention (usually, by setting) the variable &TARGETS_zonk, or whatever. -This will create a src/zonk target (for appropriate value of src/). -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). - -Perdir.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. +You can define other per-directory recursive targets too: set the +variable &TARGETS_zonk, or whatever (being sure to write &TARGETS_zonk +at the start of a line). This will create a src/zonk target (for +appropriate value of src/). 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 set in src but not lib, `make +zonk' in lib will fail. If you want to make a target exist +everywhere, += it with nothing in Prefix.sd.mk or Suffix.sd.mk (see +below). + +Prefix.sd.mk, Suffix.sd.mk, Final.sd.mk, inclusion +-------------------------------------------------- + +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. +The file Final.sd.mk in the toplevel directory is processed and +included after all the other files. + subdirmk's filter script itself sets (only) these variables: top_srcdir abs_top_srcdir @@ -147,7 +152,7 @@ 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, Final) If you `include subdirmk/regen.mk', dependency management and automatic regeneration for all of this template substitution, and for @@ -183,7 +188,7 @@ In more detail, with all the various options laid out: for build source build source This lc &file &^file $(PWD)/&file $(abs_src)/&file - directory any &/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 @@ -218,30 +223,42 @@ 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 + +&\& => & general escaping mechanism +&\$ => $ provided for $-doubling regimes +&\NEWLINE eats the newline and vanishes + +&$VARIABLE => $(sub_dir_VARIABLE) or $(TOP_VARIABLE) + VARIABLE is ASCII starting with a letter and matching \w+ & thing thing... & &^ thing thing... & @@ -255,35 +272,37 @@ 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:: $(&TARGETS_things) @@ -297,13 +316,54 @@ So pathname syntax is a subset of: which recursively implies this directory's `things'. Must be spelled exactly &TARGETS_things. &_TARGETS_things, - for example, is not magic. But mentioning &TARGETS_things in - a #-comment *does* work because the & filter does not care - about comments. + for example, is not magic. To make the target exist + without providing any prerequisites for it, write a line + containing just `&TARGETS_things +='. `all' is extra special: every directory has an `all' target, which corresponds to &TARGETS. + +Dollar doubling and macro assistance +------------------------------------ + +&$+ Starts dollar-doubling +&$- Stops dollar-doubling + Both are idempotent and local to the file or context. + +Sometimes we will show $'s being doubled inside another construct. +This means the content of the construct is $-doubled: $-doubling is +locally enabled, and restored afterwards. + +&:macro NAME => define NAME +STUFF $ THINGS .. STUFF $$ THINGS +&:endm .. endef + NAME is processed for & + +&${..$..} => ${eval ${call ..$$..}} + (matches { } pairs to find the end) + content is $-doubled (unless it contains $- to turn that off) + + Together &:macro and &${...} provide a more reasonable macro + facility than raw make. They solve the problem that make + expansions cannot directly generate multiple rules, variable, + etc.; instead, `$(eval )' must be used, but that re-expands + the argument, meaning that all the literal text must be + $-doubled. This applies to the macro text and to the + arguments. Also `$(eval $(call ...))' is an unfortunate syntax. + Hence &:macro and &${...}. + +While dollar-doubling: +- - - - - - - - - - - + +$ => $$ including $'s produced by other + &-expansions not mentioned here + +&\$ => $ +&$NN => $(NN) where N are digits +&$( => $( + + Subdirectory and variable naming -------------------------------- @@ -340,7 +400,7 @@ 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 @@ -371,6 +431,13 @@ 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 -----------------