[PATCH 2/2] AX_ELISP: New submission

From: Thien-Thi Nguyen <[email protected]>
Subject: [PATCH 2/2] AX_ELISP: New submission

I am submitting this to the Autoconf Archive in case it
might be more widely useful than for EDB, its original home.
As elisp.m4, it was mentioned in passing here:
http://lists.gnu.org/archive/html/gnu-emacs-sources/2016-11/msg00001.html

* m4/ax_elisp.m4: New file.
---
 m4/ax_elisp.m4 | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 m4/ax_elisp.m4

diff --git a/m4/ax_elisp.m4 b/m4/ax_elisp.m4
new file mode 100644
index 0000000..1794c9c
--- /dev/null
+++ b/m4/ax_elisp.m4
@@ -0,0 +1,170 @@
+# ===========================================================================
+#         https://www.gnu.org/software/autoconf-archive/ax_elisp.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_ELISP_CONFIG_FILE(FILENAME)
+#   AX_ELISP_CHECK(SYMBOL,DESCRIPTION,BODY,SUCCESS-EXPR)
+#   AX_ELISP_CHECK_FEATURE(SYMBOL)
+#   AX_ELISP_CHECK_FBOUNDP(SYMBOL,[FEATURE [...]])
+#   AX_ELISP_CHECK_BOUNDP(SYMBOL,[FEATURE [...]])
+#
+# DESCRIPTION
+#
+#   This is a simple library to check the Emacs reality by way of Emacs Lisp
+#   forms evaluated under $EMACS --batch -Q. This means you MUST have the
+#   shell variable EMACS set to a valid Emacs executable prior to the first
+#   call to any of the AX_ELISP_CHECK et al macros. Those work by saving
+#   their results to the file defined by calling AX_ELISP_CONFIG_FILE so you
+#   MUST call that prior, too. For example:
+#
+#     dnl Arrange to save config answers in $top_builddir/lisp/config.el.
+#     AX_ELISP_CONFIG_FILE([lisp/config.el])
+#
+#     dnl Set shell variable EMACS and AC_SUBST it, too.
+#     dnl (NB: This is a separate Autoconf Archive macro.)
+#     AX_PROG_EMACS
+#
+#   In the following detailed descriptions, SYMBOL stands for an Emacs Lisp
+#   symbol, which may contain hyphens, e.g., 'define-error' or 'org-src'.
+#   Likewise, FEATURE is an Emacs Lisp symbol (naming a feature). BODY and
+#   SUCCESS-EXPR are Emacs Lisp forms, zero or more for BODY and exactly one
+#   for SUCCESS-EXPR. In these forms you must take care to avoid apostrophe
+#   (U+27). Instead of 'foo, write (quote foo).
+#
+#   * AX_ELISP_CONFIG_FILE(FILENAME)
+#
+#   This arranges for future AX_ELISP_CHECK (et al) calls to save their
+#   results in FILENAME. May be called multiple times. FILENAME should be
+#   relative to the top build dir.
+#
+#   * AX_ELISP_CHECK(SYMBOL,DESCRIPTION,BODY,SUCCESS-EXPR)
+#
+#   This is the general macro that the other AX_ELISP_CHECK* macros use. It
+#   constructs a short Emacs Lisp file comprising BODY and evaluates it via
+#   $EMACS --batch -Q. The exit value of this script depends on the result
+#   of evaluating SUCCESS-EXPR: non-nil is success and nil is failure. On
+#   success, append SYMBOL on a line of its own to the config file. This
+#   macro uses AC_CACHE_CHECK and passes DESCRIPTION to it.
+#
+#   * AX_ELISP_CHECK_FEATURE(FEATURE)
+#
+#   This checks if (require (quote FEATURE)) is successful. If so, add
+#   featurep-FEATURE to the config file (NB the "featurep-" prefix).
+#
+#   * AX_ELISP_CHECK_FBOUNDP(SYMBOL,[FEATURE [...]])
+#
+#   This checks if (fboundp (quote SYMBOL)) is successful. If so, append
+#   SYMBOL to the config file. Optional 2nd arg is a space-separated list of
+#   features to require prior to the fboundp check.
+#
+#   * AX_ELISP_CHECK_BOUNDP(SYMBOL,[FEATURE [...]])
+#
+#   This checks if (boundp (quote SYMBOL)) is successful. If so, append
+#   SYMBOL to the config file. Optional 2nd arg is a space-separated list of
+#   features to require prior to the boundp check.
+#
+# LICENSE
+#
+#   Copyright (c) 2016-2017 Thien-Thi Nguyen
+#
+#   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 3 of the License, 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 program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 1
+
+AC_DEFUN([AX_ELISP_CONFIG_FILE],[dnl
+dnl 1 -- relative filename (from ‘top_srcdir’)
+m4_define([AX_ELISP__CONFIG_FILENAME],[$1])dnl
+])dnl
+
+
+AC_DEFUN([AX_ELISP__PREP],[dnl
+AS_IF([AS_VAR_TEST_SET([EMACS])],,dnl
+  [AC_MSG_ERROR([No value for EMACS])])
+dnl FIXME: Check at autoconf-time that AX_ELISP__CONFIG_FILENAME is set.
+dnl        (If not, or if the value is unsuitable, throw fatal error.)
+rm -f AX_ELISP__CONFIG_FILENAME
+touch AX_ELISP__CONFIG_FILENAME
+])dnl
+
+
+AC_DEFUN([AX_ELISP_CHECK],[dnl
+dnl 1 -- Emacs Lisp symbol to add to config file if "success"
+dnl 2 -- description
+dnl 3 -- Emacs Lisp body (zero or more forms)
+dnl 4 -- Emacs Lisp expression for "success"
+AC_REQUIRE([AX_ELISP__PREP])dnl
+AS_VAR_PUSHDEF([CV],[elisp_cv_$1])dnl
+AC_CACHE_CHECK([$2],[CV],[dnl
+cat >conftest.el <<AX_ELISP__EOF
+$3
+(kill-emacs (if $4 0 1))
+AX_ELISP__EOF
+AS_IF([$EMACS --batch -Q -l conftest.el 1>&5 2>&5],[CV=yes],[CV=no])])
+AS_IF([test yes = $[]CV],[echo "$1" >> AX_ELISP__CONFIG_FILENAME])
+AS_VAR_POPDEF([CV])dnl
+])dnl
+
+
+AC_DEFUN([AX_ELISP_CHECK_FEATURE],[dnl
+dnl 1 -- Emacs Lisp symbol (a feature name)
+AC_REQUIRE([AX_ELISP__PREP])dnl
+AX_ELISP_CHECK([featurep-$1],[if $EMACS supports feature ‘$1’],[dnl
+(require (quote $1))
+],[dnl
+(featurep (quote $1))
+])])
+
+
+AC_DEFUN([AX_ELISP_CHECK_FBOUNDP],[dnl
+dnl 1 -- Emacs Lisp symbol
+dnl 2 -- (optional) space-separated list of features to ‘require’
+AX_ELISP_CHECK([$1],[if ‘$1’ is defined],[dnl
+m4_foreach([FEATURE],m4_split(m4_normalize($2)),[dnl
+(require 'FEATURE)
+])],[(fboundp '$1)])])dnl
+
+
+AC_DEFUN([AX_ELISP_CHECK_BOUNDP],[dnl
+dnl 1 -- Emacs Lisp symbol
+dnl 2 -- (optional) space-separated list of features to ‘require’
+AX_ELISP_CHECK([$1],[if ‘$1’ is defined],[dnl
+m4_foreach([FEATURE],m4_split(m4_normalize($2)),[dnl
+(require 'FEATURE)
+])],[(boundp '$1)])])dnl
+
+
+dnl TODO:
+dnl - Add error checking (see FIXME in code).
+dnl - Validate m4 mumblings -- is this the right crazy?!
+dnl - Add customization of $EMACS invocation.
+dnl
+dnl Local variables:
+dnl mode: autoconf
+dnl End:
+dnl ax_elisp.m4 ends here
-- 
1.9.1

-- 
Thien-Thi Nguyen -----------------------------------------------
 (defun responsep (query)
   (pcase (context query)
     (`(technical ,ml) (correctp ml))
     ...))                              748E A0E8 1CB8 A748 9BFA
--------------------------------------- 6CE4 6703 2224 4C80 7502

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