/*
 *	aegis - project change supervisor
 *	Copyright (C) 1997, 1999 Peter Miller;
 *	All rights reserved.
 *
 *	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 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, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to implement the builtin getenv function
 */

#include <ac/stdlib.h>

#include <aer/expr.h>
#include <aer/func/getenv.h>
#include <aer/value/error.h>
#include <aer/value/integer.h>
#include <aer/value/string.h>
#include <aer/value/time.h>
#include <error.h>
#include <sub.h>


static int verify _((rpt_expr_ty *));

static int
verify(ep)
	rpt_expr_ty	*ep;
{
	return (ep->nchild == 1);
}


static rpt_value_ty *run _((rpt_expr_ty *, size_t, rpt_value_ty **));

static rpt_value_ty *
run(ep, argc, argv)
	rpt_expr_ty	*ep;
	size_t		argc;
	rpt_value_ty	**argv;
{
	char		*cp;
	rpt_value_ty	*tmp;
	string_ty       *s;
	rpt_value_ty	*result;

	assert(argc == 1);

	/*
	 * Coerce the argument to a string.
	 * It is an error if it can't be.
	 */
	tmp = rpt_value_stringize(argv[0]);
	if (tmp->method->type != rpt_value_type_string)
	{
		sub_context_ty	*scp;

		scp = sub_context_new();
		rpt_value_free(tmp);
		sub_var_set_charstar(scp, "Function", "getenv");
		sub_var_set_charstar(scp, "Number", "1");
		sub_var_set_charstar(scp, "Name", argv[0]->method->name);
		s =
			subst_intl
			(
				scp,
    i18n("$function: argument $number: string value required (was given $name)")
			);
		sub_context_delete(scp);
		result = rpt_value_error(ep->pos, s);
		str_free(s);
		return result;
	}

	/*
	 * Scan the string and try to make a time out of it.
	 * It is an error if this can't be done.
	 */
	s = rpt_value_string_query(tmp);
	cp = getenv(s->str_text);
	if (!cp)
		cp = "";
	rpt_value_free(tmp);

	/*
	 * build the return value
	 */
	s = str_from_c(cp);
	result = rpt_value_string(s);
	str_free(s);
	return result;
}


rpt_func_ty rpt_func_getenv =
{
	"getenv",
	1, /* optimizable */
	verify,
	run,
};