+# GUILE_PROGS -- set paths to Guile interpreter, config and tool programs
+#
+# Usage: GUILE_PROGS([VERSION])
+#
+# This macro looks for programs @code{guile} and @code{guild}, setting
+# variables @var{GUILE} and @var{GUILD} to their paths, respectively.
+# If @code{guile} is not found, signal an error.
+#
+# By default, this macro will search for the latest stable version of
+# Guile (e.g. 2.0). x.y or x.y.z versions can be specified. If an older
+# version is found, the macro will signal an error.
+#
+# The effective version of the found @code{guile} is set to
+# @var{GUILE_EFFECTIVE_VERSION}. This macro ensures that the effective
+# version is compatible with the result of a previous invocation of
+# @code{GUILE_FLAGS}, if any.
+#
+# As a legacy interface, it also looks for @code{guile-config} and
+# @code{guile-tools}, setting @var{GUILE_CONFIG} and @var{GUILE_TOOLS}.
+#
+# The variables are marked for substitution, as by @code{AC_SUBST}.
+#
+AC_DEFUN([GUILE_PROGS],
+ [AC_PATH_PROG(GUILE,guile)
+ _guile_required_version="m4_default([$1], [$GUILE_EFFECTIVE_VERSION])"
+ if test -z "$_guile_required_version"; then
+ _guile_required_version=2.0
+ fi
+ if test "$GUILE" = "" ; then
+ AC_MSG_ERROR([guile required but not found])
+ fi
+ AC_SUBST(GUILE)
+
+ _guile_effective_version=`$GUILE -c "(display (effective-version))"`
+ if test -z "$GUILE_EFFECTIVE_VERSION"; then
+ GUILE_EFFECTIVE_VERSION=$_guile_effective_version
+ elif test "$GUILE_EFFECTIVE_VERSION" != "$_guile_effective_version"; then
+ AC_MSG_ERROR([found development files for Guile $GUILE_EFFECTIVE_VERSION, but $GUILE has effective version $_guile_effective_version])
+ fi
+
+ _guile_major_version=`$GUILE -c "(display (major-version))"`
+ _guile_minor_version=`$GUILE -c "(display (minor-version))"`
+ _guile_micro_version=`$GUILE -c "(display (micro-version))"`
+ _guile_prog_version="$_guile_major_version.$_guile_minor_version.$_guile_micro_version"
+
+ AC_MSG_CHECKING([for Guile version >= $_guile_required_version])
+ _major_version=`echo $_guile_required_version | cut -d . -f 1`
+ _minor_version=`echo $_guile_required_version | cut -d . -f 2`
+ _micro_version=`echo $_guile_required_version | cut -d . -f 3`
+ if test "$_guile_major_version" -ge "$_major_version"; then
+ if test "$_guile_minor_version" -ge "$_minor_version"; then
+ if test -n "$_micro_version"; then
+ if test "$_guile_micro_version" -lt "$_micro_version"; then
+ AC_MSG_ERROR([Guile $_guile_required_version required, but $_guile_prog_version found])
+ fi
+ fi
+ elif test "$GUILE_EFFECTIVE_VERSION" = "$_major_version.$_minor_version" -a -z "$_micro_version"; then
+ # Allow prereleases that have the right effective version.
+ true
+ else
+ as_fn_error $? "Guile $_guile_required_version required, but $_guile_prog_version found" "$LINENO" 5
+ fi
+ else
+ AC_MSG_ERROR([Guile $_guile_required_version required, but $_guile_prog_version found])
+ fi
+ AC_MSG_RESULT([$_guile_prog_version])
+
+ AC_PATH_PROG(GUILD,guild)
+ AC_SUBST(GUILD)
+
+ AC_PATH_PROG(GUILE_CONFIG,guile-config)
+ AC_SUBST(GUILE_CONFIG)
+ if test -n "$GUILD"; then
+ GUILE_TOOLS=$GUILD
+ else
+ AC_PATH_PROG(GUILE_TOOLS,guile-tools)
+ fi
+ AC_SUBST(GUILE_TOOLS)
+ ])
+