When Guile is installed, a set of autoconf macros is also installed as PREFIX/share/aclocal/guile.m4. This chapter documents the macros provided in that file, as well as the high-level guile-tool Autofrisk. @xref{Top,The GNU Autoconf Manual,,autoconf}, for more info.
As explained elsewhere (@xref{Top,The GNU Autoconf Manual,,autoconf}), any package needs configuration at build-time. If your package uses Guile (or uses a package that in turn uses Guile), you probably need to know what specific Guile features are available and details about them.
The way to do this is to write feature tests and arrange for their execution
by the `configure' script, typically by adding the tests to
`configure.ac', and running autoconf to create `configure'.
Users of your package then run `configure' in the normal way.
Macros are a way to make common feature tests easy to express. Autoconf provides a wide range of macros (@xref{Existing Tests,,,autoconf}), and Guile installation provides Guile-specific tests in the areas of: program detection, compilation flags reporting, and Scheme module checks.
The macro names all begin with "GUILE_".
Using the autoconf macros is straightforward: Add the macro "calls" (actually
instantiations) to `configure.ac', run aclocal, and finally,
run autoconf. If your system doesn't have guile.m4 installed, place
the desired macro definitions (AC_DEFUN forms) in `acinclude.m4',
and aclocal will do the right thing.
Some of the macros can be used inside normal shell constructs: if foo ;
then GUILE_BAZ ; fi, but this is not guaranteed. It's probably a good idea
to instantiate macros at top-level.
We now include two examples, one simple and one complicated.
The first example is for a package that uses libguile, and thus needs to know
how to compile and link against it. So we use GUILE_FLAGS to set the
vars GUILE_CFLAGS and GUILE_LDFLAGS, which are automatically
substituted in the Makefile.
In configure.ac:
GUILE_FLAGS
In Makefile.in:
GUILE_CFLAGS = @GUILE_CFLAGS@
GUILE_LDFLAGS = @GUILE_LDFLAGS@
myprog.o: myprog.c
$(CC) -o $ $(GUILE_CFLAGS) $<
myprog: myprog.o
$(CC) -o $ $< $(GUILE_LDFLAGS)
The second example is for a package of Guile Scheme modules that uses an
external program and other Guile Scheme modules (some might call this a "pure
scheme" package). So we use the GUILE_SITE_DIR macro, a regular
AC_PATH_PROG macro, and the GUILE_MODULE_AVAILABLE macro.
In configure.ac:
GUILE_SITE_DIR
probably_wont_work=""
# pgtype pgtable
GUILE_MODULE_AVAILABLE(have_guile_pg, (database postgres))
test $have_guile_pg = no &&
probably_wont_work="(my pgtype) (my pgtable) $probably_wont_work"
# gpgutils
AC_PATH_PROG(GNUPG,gpg)
test x"$GNUPG" = x &&
probably_wont_work="(my gpgutils) $probably_wont_work"
if test ! "$probably_wont_work" = "" ; then
p=" ***"
echo
echo "$p"
echo "$p NOTE:"
echo "$p The following modules probably won't work:"
echo "$p $probably_wont_work"
echo "$p They can be installed anyway, and will work if their"
echo "$p dependencies are installed later. Please see README."
echo "$p"
echo
fi
In Makefile.in:
instdir = @GUILE_SITE@/my
install:
$(INSTALL) my/*.scm $(instdir)
The guile-tools autofrisk command looks for the file `modules.af'
in the current directory and writes out `modules.af.m4' containing
autoconf definitions for AUTOFRISK_CHECKS and AUTOFRISK_SUMMARY.
See section Autoconf Background, and See section Using Autoconf Macros, for more info.
The modules.af file consists of a series of configuration forms (Scheme lists), which have one of the following formats:
(files-glob PATTERN ...) ;; required (non-critical-external MODULE ...) ;; optional (non-critical-internal MODULE ...) ;; optional (programs (MODULE PROG ...) ...) ;; optional (pww-varname VARNAME) ;; optional
pattern is a string that may contain "*" and "?" characters to be
expanded into filenames. module is a list of symbols naming a module,
such as `(srfi srfi-1)'. varname is a shell-safe name to use instead of
probably_wont_work, the default. This var is passed to `AC_SUBST'.
prog is a string that names a program, such as "gpg".
Autofrisk expands the files-glob pattern(s) into a list of files, scans
each file's module definition form(s), and constructs a module dependency
graph wherein modules defined by define-module are considered
internal and the remaining, external. For each external module
that has an internal dependency, Autofrisk emits a
GUILE_MODULE_REQUIRED check (see section Autoconf Macros), which altogether
form the body of AUTOFRISK_CHECKS.
GUILE_MODULE_REQUIRED causes the `configure' script to exit with
an error message if the specified module is not available; it enforces a
strong dependency. You can temper dependency strength by using the
non-critical-external and non-critical-internal configuration
forms in modules.af. For graph edges that touch such non-critical modules,
Autofrisk uses GUILE_MODULE_AVAILABLE, and arranges for
AUTOFRISK_SUMMARY to display a warning if they are not found.
The shell code resulting from the expansion of AUTOFRISK_CHECKS and
AUTOFRISK_SUMMARY uses the shell variable probably_wont_work to
collect the names of unfound non-critical modules. If this bothers you, use
configuration form (pww-name foo) in modules.af.
Although Autofrisk does not detect when a module uses a program (for example,
in a system call), it can generate AC_PATH_PROG forms anyway if
you use the programs configuration form in modules.af. These are
collected into AUTOCONF_CHECKS.
See section Using Autofrisk, for some modules.af examples.
Using Autofrisk (see section Autofrisk) involves writing `modules.af' and adding two macro calls to `configure.in'. Here is an example of the latter:
AUTOFRISK_CHECKS AUTOFRISK_SUMMARY
Here is an adaptation of the second "GUILE_*" example (see section Using Autoconf Macros) that does basically the same thing.
(files-glob "my/*.scm") (non-critical-external (database postgres)) (programs ((my gpgutils) "gpg")) ;; (my gpgutils) uses "gpg"
If the SRFI modules (see section SRFI Support Modules) were a separate package, we could
use guile-tools frisk to find out its dependencies:
$ guile-tools frisk srfi/*.scm 13 files, 18 modules (13 internal, 5 external), 9 edges x (ice-9 and-let-star) regular (srfi srfi-2) x (ice-9 syncase) regular (srfi srfi-11) x (ice-9 rdelim) regular (srfi srfi-10) x (ice-9 receive) regular (srfi srfi-8) regular (srfi srfi-1) x (ice-9 session) regular (srfi srfi-1)
Then, we could use the following modules.af to help configure it:
(files-glob "srfi/*.scm") (non-critical-external ;; relatively recent (ice-9 rdelim) (ice-9 receive) (ice-9 and-let-star)) (pww-varname not_fully_supported)
Go to the first, previous, next, last section, table of contents.