/*
 *	aegis - project change supervisor
 *	Copyright (C) 1994-1996, 1999, 2002, 2003 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 manipulate unary expressions
 */

#include <aer/expr/neg.h>
#include <aer/value/boolean.h>
#include <aer/value/error.h>
#include <aer/value/integer.h>
#include <aer/value/real.h>
#include <error.h>
#include <sub.h>
#include <trace.h>


static rpt_value_ty *
neg_evaluate(rpt_expr_ty *this_thing)
{
    sub_context_ty  *scp;
    rpt_value_ty    *v1;
    rpt_value_ty    *v2;
    rpt_value_ty    *vp;
    string_ty       *s;

    /*
     * evaluate the argument
     */
    trace(("neg::evaluate()\n{\n"));
    assert(this_thing->nchild == 1);
    v1 = rpt_expr_evaluate(this_thing->child[0], 1);
    if (v1->method->type == rpt_value_type_error)
    {
	trace(("}\n"));
	return v1;
    }

    /*
     * coerce the argument to an arithmetic type
     * (will not give error if can't, will copy instead)
     */
    v2 = rpt_value_arithmetic(v1);
    rpt_value_free(v1);

    /*
     * the type of the result depends on
     * the types of the argument
     */
    switch (v2->method->type)
    {
    case rpt_value_type_real:
	vp = rpt_value_real(-rpt_value_real_query(v2));
	trace(("vp = %g real\n", rpt_value_real_query(vp)));
	break;

    case rpt_value_type_integer:
	vp = rpt_value_integer(-rpt_value_integer_query(v2));
	trace(("vp = %ld integer\n", rpt_value_integer_query(vp)));
	break;

    default:
	scp = sub_context_new();
	sub_var_set_charstar(scp, "Name", v2->method->name);
	s = subst_intl(scp, i18n("illegal negative ($name)"));
	sub_context_delete(scp);
	vp = rpt_value_error(this_thing->child[0]->pos, s);
	str_free(s);
	break;
    }
    rpt_value_free(v2);
    trace(("return %08lX;\n", (long)vp));
    trace(("}\n"));
    return vp;
}


static rpt_expr_method_ty neg_method =
{
    sizeof(rpt_expr_ty),
    "negative",
    0, /* construct */
    0, /* destruct */
    neg_evaluate,
    0, /* lvalue */
};


rpt_expr_ty *
rpt_expr_neg(rpt_expr_ty *a)
{
    rpt_expr_ty     *this_thing;

    this_thing = rpt_expr_alloc(&neg_method);
    rpt_expr_append(this_thing, a);
    return this_thing;
}


static rpt_value_ty *
pos_evaluate(rpt_expr_ty *this_thing)
{
    sub_context_ty  *scp;
    rpt_value_ty    *v1;
    rpt_value_ty    *v2;
    rpt_value_ty    *vp;
    string_ty       *s;

    /*
     * evaluate the argument
     */
    trace(("pos::evaluate()\n{\n"));
    assert(this_thing->nchild == 1);
    v1 = rpt_expr_evaluate(this_thing->child[0], 1);
    if (v1->method->type == rpt_value_type_error)
    {
	trace(("}\n"));
	return v1;
    }

    /*
     * coerce the argument to an arithmetic type
     *	(will not give error if can't, will copy instead)
     */
    v2 = rpt_value_arithmetic(v1);
    rpt_value_free(v1);

    /*
     * the type of the result depends on
     * the types of the argument
     */
    switch (v2->method->type)
    {
    case rpt_value_type_real:
    case rpt_value_type_integer:
	vp = rpt_value_copy(v2);
	break;

    default:
	scp = sub_context_new();
	sub_var_set_charstar(scp, "Name", v2->method->name);
	s = subst_intl(scp, i18n("illegal positive ($name)"));
	sub_context_delete(scp);
	vp = rpt_value_error(this_thing->child[0]->pos, s);
	str_free(s);
	break;
    }
    rpt_value_free(v2);
    trace(("return %08lX;\n", (long)vp));
    trace(("}\n"));
    return vp;
}


static rpt_expr_method_ty pos_method =
{
    sizeof(rpt_expr_ty),
    "positive",
    0, /* construct */
    0, /* destruct */
    pos_evaluate,
    0, /* lvalue */
};


rpt_expr_ty *
rpt_expr_pos(rpt_expr_ty *a)
{
    rpt_expr_ty     *this_thing;

    this_thing = rpt_expr_alloc(&pos_method);
    rpt_expr_append(this_thing, a);
    return this_thing;
}
