## Autoconf macros for working with Guile.
##
##   Copyright (C) 1998,2001 Free Software Foundation, Inc.
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2, or (at your option)
## any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this software; see the file COPYING.  If not, write to
## the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
## Boston, MA 02111-1307 USA
##
## As a special exception, the Free Software Foundation gives permission
## for additional uses of the text contained in its release of GUILE.
##
## The exception is that, if you link the GUILE library with other files
## to produce an executable, this does not by itself cause the
## resulting executable to be covered by the GNU General Public License.
## Your use of that executable is in no way restricted on account of
## linking the GUILE library code into it.
##
## This exception does not however invalidate any other reasons why
## the executable file might be covered by the GNU General Public License.
##
## This exception applies only to the code released by the
## Free Software Foundation under the name GUILE.  If you copy
## code from other Free Software Foundation releases into a copy of
## GUILE, as the General Public License permits, the exception does
## not apply to the code that you add in this way.  To avoid misleading
## anyone as to the status of such modified files, you must delete
## this exception notice from them.
##
## If you write modifications of your own for GUILE, it is your choice
## whether to permit this exception to apply to your modifications.
## If you do not wish that, delete this exception notice.

## Index
## -----
##
## GUILE_PROGS -- set paths to Guile interpreter, config and tool programs
## GUILE_FLAGS -- set flags for compiling and linking with Guile
## GUILE_SITE_DIR -- find path to Guile "site" directory
## GUILE_CHECK -- evaluate Guile Scheme code and capture the return value
## GUILE_MODULE_CHECK -- check feature of a Guile Scheme module
## GUILE_MODULE_AVAILABLE -- check availability of a Guile Scheme module
## GUILE_MODULE_REQUIRED -- fail if a Guile Scheme module is unavailable
## GUILE_MODULE_EXPORTS -- check if a module exports a variable
## GUILE_MODULE_REQUIRED_EXPORT -- fail if a module doesn't export a variable

## Code
## ----

# GUILE_PROGS -- set paths to Guile interpreter, config and tool programs
#
# Usage: GUILE_PROGS
#
# This macro looks for programs `guile', `guile-config' and `guile-tools',
# and sets variables GUILE, GUILE_CONFIG and GUILE_TOOLS, to their paths,
# respectively.  If either of the first two are not found, signal error.
#
# The variables are marked for substitution, as by AC_SUBST.
#
AC_DEFUN([GUILE_PROGS],
 [AC_PATH_PROG(GUILE,guile)
  if test "$GUILE" = "" ; then
      AC_MSG_ERROR([guile required but not found])
  fi
  AC_SUBST(GUILE)
  AC_PATH_PROG(GUILE_CONFIG,guile-config)
  if test "$GUILE_CONFIG" = "" ; then
      AC_MSG_ERROR([guile-config required but not found])
  fi
  AC_SUBST(GUILE_CONFIG)
  AC_PATH_PROG(GUILE_TOOLS,guile-tools)
  AC_SUBST(GUILE_TOOLS)
 ])

# GUILE_FLAGS -- set flags for compiling and linking with Guile
#
# Usage: GUILE_FLAGS
#
# This macro runs the `guile-config' script, installed with Guile,
# to find out where Guile's header files and libraries are
# installed.  It sets two variables, GUILE_CFLAGS and GUILE_LDFLAGS.
#
# GUILE_CFLAGS: flags to pass to a C or C++ compiler to build code that
# uses Guile header files.  This is almost always just a -I flag.
#
# GUILE_LDFLAGS: flags to pass to the linker to link a program against
# Guile.  This includes `-lguile' for the Guile library itself, any
# libraries that Guile itself requires (like -lqthreads), and so on.  It
# may also include a -L flag to tell the compiler where to find the
# libraries.
#
# The variables are marked for substitution, as by AC_SUBST.
#
AC_DEFUN([GUILE_FLAGS],[
## The GUILE_FLAGS macro.
  ## First, let's just see if we can find Guile at all.
  AC_MSG_CHECKING(for Guile)
  guile-config link > /dev/null || {
    echo "configure: cannot find guile-config; is Guile installed?" 1>&2
    exit 1
  }
  GUILE_CFLAGS="`guile-config compile`"
  GUILE_LDFLAGS="`guile-config link`"
  AC_SUBST(GUILE_CFLAGS)
  AC_SUBST(GUILE_LDFLAGS)
  AC_MSG_RESULT(yes)
])

# GUILE_SITE_DIR -- find path to Guile "site" directory
#
# Usage: GUILE_SITE_DIR
#
# This looks for Guile's "site" directory, usually something like
# PREFIX/share/guile/site, and sets var GUILE_SITE to the path.
# Note that the var name is different from the macro name.
#
# The variable is marked for substitution, as by AC_SUBST.
#
AC_DEFUN([GUILE_SITE_DIR],
 [AC_REQUIRE([GUILE_PROGS])dnl
  AC_MSG_CHECKING(for Guile site directory)
  GUILE_SITE=`[$GUILE_CONFIG] info pkgdatadir`/site
  AC_MSG_RESULT($GUILE_SITE)
  AC_SUBST(GUILE_SITE)
 ])

# GUILE_CHECK -- evaluate Guile Scheme code and capture the return value
#
# Usage: GUILE_CHECK_RETVAL(var,check)
#
# $1 is a shell variable name to be set to the return value
# $2 is a Guile Scheme expression, evaluated with "$GUILE -c", and
#    returning either 0 or non-#f to indicate the check passed.
#    Non-0 number or #f indicates failure.
#    Avoid using the character "#" since that confuses autoconf.
#
AC_DEFUN([GUILE_CHECK],
 [AC_REQUIRE([GUILE_PROGS])
  $GUILE -c "$2" > /dev/null 2>&1
  $1=$?
 ])

# GUILE_MODULE_CHECK -- check feature of a Guile Scheme module
#
# Usage: GUILE_MODULE_CHECK(var,module,featuretest,description)
#
# $1 is a shell variable name to be set to "yes" or "no"
# $2 is a list of symbols, like: (ice-9 common-list)
# $3 is an expression acceptable to GUILE_CHECK, q.v.
# $4 is a present-tense verb phrase (passed to AC_MSG_CHECKING)
#
AC_DEFUN([GUILE_MODULE_CHECK],
         [AC_MSG_CHECKING([if $2 $4])
	  GUILE_CHECK($1,(use-modules $2) (exit ((lambda () $3))))
	  if test "$$1" = "0" ; then $1=yes ; else $1=no ; fi
          AC_MSG_RESULT($$1)
         ])

# GUILE_MODULE_AVAILABLE -- check availability of a Guile Scheme module
#
# Usage: GUILE_MODULE_AVAILABLE(var,module)
#
# $1 is a shell variable name to be set to "yes" or "no"
# $2 is a list of symbols, like: (ice-9 common-list)
#
AC_DEFUN([GUILE_MODULE_AVAILABLE],
         [GUILE_MODULE_CHECK($1,$2,0,is available)
         ])

# GUILE_MODULE_REQUIRED -- fail if a Guile Scheme module is unavailable
#
# Usage: GUILE_MODULE_REQUIRED(symlist)
#
# $1 is a list of symbols, WITHOUT surrounding parens, like: ice-9 common-list
#
AC_DEFUN([GUILE_MODULE_REQUIRED],
         [GUILE_MODULE_AVAILABLE(ac_guile_module_required, ($1))
          if test "$ac_guile_module_required" = "no" ; then
              AC_MSG_ERROR([required guile module not found: ($1)])
          fi
         ])

# GUILE_MODULE_EXPORTS -- check if a module exports a variable
#
# Usage: GUILE_MODULE_EXPORTS(var,module,modvar)
#
# $1 is a shell variable to be set to "yes" or "no"
# $2 is a list of symbols, like: (ice-9 common-list)
# $3 is the Guile Scheme variable to check
#
AC_DEFUN([GUILE_MODULE_EXPORTS],
 [GUILE_MODULE_CHECK($1,$2,$3,exports `$3')
 ])

# GUILE_MODULE_REQUIRED_EXPORT -- fail if a module doesn't export a variable
#
# Usage: GUILE_MODULE_REQUIRED_EXPORT(module,modvar)
#
# $1 is a list of symbols, like: (ice-9 common-list)
# $2 is the Guile Scheme variable to check
#
AC_DEFUN([GUILE_MODULE_REQUIRED_EXPORT],
 [GUILE_MODULE_EXPORTS(guile_module_required_export,$1,$2)
  if test "$guile_module_required_export" = "no" ; then
      AC_MSG_ERROR([module $1 does not export $2; required])
  fi
 ])

## guile.m4 ends here