/*
 *	aegis - project change supervisor
 *	Copyright (C) 1994, 1995, 1996, 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 manipulate plus expressions
 */

#include <aer/expr/plus.h>
#include <aer/value/error.h>
#include <aer/value/list.h>
#include <aer/value/integer.h>
#include <aer/value/real.h>
#include <aer/value/string.h>
#include <error.h>
#include <sub.h>
#include <trace.h>

#define PAIR(a, b)	((a) * rpt_value_type_MAX + (b))


static rpt_value_ty *plus_evaluate _((rpt_expr_ty *));

static rpt_value_ty *
plus_evaluate(this)
	rpt_expr_ty	*this;
{
	sub_context_ty	*scp;
	rpt_value_ty	*lv1;
	rpt_value_ty	*lv2;
	rpt_value_ty	*rv1;
	rpt_value_ty	*rv2;
	rpt_value_ty	*vp;
	string_ty	*s;

	/*
	 * evaluate the left hand side
	 */
	trace(("plus::evaluate()\n{\n"/*}*/));
	assert(this->nchild == 2);
	lv1 = rpt_expr_evaluate(this->child[0], 1);
	if (lv1->method->type == rpt_value_type_error)
	{
		trace((/*{*/"}\n"));
		return lv1;
	}

	/*
	 * coerce the left hand side to an arithmetic type
	 *	(will not give error if can't, will copy instead)
	 */
	lv2 = rpt_value_arithmetic(lv1);
	rpt_value_free(lv1);

	/*
	 * evaluate the right hand side
	 */
	rv1 = rpt_expr_evaluate(this->child[1], 1);
	if (rv1->method->type == rpt_value_type_error)
	{
		rpt_value_free(lv2);
		trace((/*{*/"}\n"));
		return rv1;
	}

	/*
	 * coerce the right hand side to an arithmetic type
	 *	(will not give error if can't, will copy instead)
	 */
	rv2 = rpt_value_arithmetic(rv1);
	rpt_value_free(rv1);

	/*
	 * the type of the result depends on
	 * the types of the operands
	 */
	switch (PAIR(lv2->method->type, rv2->method->type))
	{
	case PAIR(rpt_value_type_real, rpt_value_type_real):
		vp =
			rpt_value_real
			(
				rpt_value_real_query(lv2)
			+
				rpt_value_real_query(rv2)
			);
		trace(("vp = %g real\n", rpt_value_real_query(vp)));
		break;

	case PAIR(rpt_value_type_real, rpt_value_type_integer):
		vp =
			rpt_value_real
			(
				rpt_value_real_query(lv2)
			+
				rpt_value_integer_query(rv2)
			);
		trace(("vp = %g real\n", rpt_value_real_query(vp)));
		break;

	case PAIR(rpt_value_type_integer, rpt_value_type_real):
		vp =
			rpt_value_real
			(
				rpt_value_integer_query(lv2)
			+
				rpt_value_real_query(rv2)
			);
		trace(("vp = %g real\n", rpt_value_real_query(vp)));
		break;

	case PAIR(rpt_value_type_integer, rpt_value_type_integer):
		vp =
			rpt_value_integer
			(
				rpt_value_integer_query(lv2)
			+
				rpt_value_integer_query(rv2)
			);
		trace(("vp = %ld integer\n", rpt_value_integer_query(vp)));
		break;

	default:
		scp = sub_context_new();
		sub_var_set_charstar(scp, "Name1", lv2->method->name);
		sub_var_set_charstar(scp, "Name2", rv2->method->name);
		s = subst_intl(scp, i18n("illegal addition ($name1 + $name2)"));
		sub_context_delete(scp);
		vp = rpt_value_error(this->pos, s);
		str_free(s);
		break;
	}
	rpt_value_free(lv2);
	rpt_value_free(rv2);
	trace(("return %08lX;\n", (long)vp));
	trace((/*{*/"}\n"));
	return vp;
}


static rpt_expr_method_ty plus_method =
{
	sizeof(rpt_expr_ty),
	"plus",
	0, /* construct */
	0, /* destruct */
	plus_evaluate,
	0, /* lvalue */
};


rpt_expr_ty *
rpt_expr_plus(a, b)
	rpt_expr_ty	*a;
	rpt_expr_ty	*b;
{
	rpt_expr_ty	*this;

	this = rpt_expr_alloc(&plus_method);
	rpt_expr_append(this, a);
	rpt_expr_append(this, b);
	return this;
}


static rpt_value_ty *minus_evaluate _((rpt_expr_ty *));

static rpt_value_ty *
minus_evaluate(this)
	rpt_expr_ty	*this;
{
	sub_context_ty	*scp;
	rpt_value_ty	*lv1;
	rpt_value_ty	*lv2;
	rpt_value_ty	*rv1;
	rpt_value_ty	*rv2;
	rpt_value_ty	*vp;
	string_ty	*s;

	/*
	 * evaluate the left hand side
	 */
	trace(("minus::evaluate()\n{\n"/*}*/));
	assert(this->nchild == 2);
	lv1 = rpt_expr_evaluate(this->child[0], 1);
	if (lv1->method->type == rpt_value_type_error)
	{
		trace((/*{*/"}\n"));
		return lv1;
	}

	/*
	 * coerce the left hand side to an arithmetic type
	 *	(will not give error if can't, will copy instead)
	 */
	lv2 = rpt_value_arithmetic(lv1);
	rpt_value_free(lv1);

	/*
	 * evaluate the right hand side
	 */
	rv1 = rpt_expr_evaluate(this->child[1], 1);
	if (rv1->method->type == rpt_value_type_error)
	{
		rpt_value_free(lv2);
		trace((/*{*/"}\n"));
		return rv1;
	}

	/*
	 * coerce the right hand side to an arithmetic type
	 *	(will not give error if can't, will copy instead)
	 */
	rv2 = rpt_value_arithmetic(rv1);
	rpt_value_free(rv1);

	/*
	 * the type of the result depends on
	 * the types of the operands
	 */
	switch (PAIR(lv2->method->type, rv2->method->type))
	{
	case PAIR(rpt_value_type_real, rpt_value_type_real):
		vp =
			rpt_value_real
			(
				rpt_value_real_query(lv2)
			-
				rpt_value_real_query(rv2)
			);
		trace(("vp = %g real\n", rpt_value_real_query(vp)));
		break;

	case PAIR(rpt_value_type_real, rpt_value_type_integer):
		vp =
			rpt_value_real
			(
				rpt_value_real_query(lv2)
			-
				rpt_value_integer_query(rv2)
			);
		trace(("vp = %g real\n", rpt_value_real_query(vp)));
		break;

	case PAIR(rpt_value_type_integer, rpt_value_type_real):
		vp =
			rpt_value_real
			(
				rpt_value_integer_query(lv2)
			-
				rpt_value_real_query(rv2)
			);
		trace(("vp = %g real\n", rpt_value_real_query(vp)));
		break;

	case PAIR(rpt_value_type_integer, rpt_value_type_integer):
		vp =
			rpt_value_integer
			(
				rpt_value_integer_query(lv2)
			-
				rpt_value_integer_query(rv2)
			);
		trace(("vp = %ld integer\n", rpt_value_integer_query(vp)));
		break;

	default:
		scp = sub_context_new();
		sub_var_set_charstar(scp, "Name1", lv2->method->name);
		sub_var_set_charstar(scp, "Name2", rv2->method->name);
		s =
			subst_intl
			(
				scp,
				i18n("illegal subtraction ($name1 - $name2)")
			);
		sub_context_delete(scp);
		vp = rpt_value_error(this->pos, s);
		str_free(s);
		break;
	}
	rpt_value_free(lv2);
	rpt_value_free(rv2);
	trace(("return %08lX;\n", (long)vp));
	trace((/*{*/"}\n"));
	return vp;
}


static rpt_expr_method_ty minus_method =
{
	sizeof(rpt_expr_ty),
	"minus",
	0, /* construct */
	0, /* destruct */
	minus_evaluate,
	0, /* lvalue */
};


rpt_expr_ty *
rpt_expr_minus(a, b)
	rpt_expr_ty	*a;
	rpt_expr_ty	*b;
{
	rpt_expr_ty	*this;

	this = rpt_expr_alloc(&minus_method);
	rpt_expr_append(this, a);
	rpt_expr_append(this, b);
	return this;
}


static rpt_value_ty *join_evaluate _((rpt_expr_ty *));

static rpt_value_ty *
join_evaluate(this)
	rpt_expr_ty	*this;
{
	sub_context_ty	*scp;
	rpt_value_ty	*v1;
	rpt_value_ty	*v2;
	rpt_value_ty	*result;
	string_ty	*s;

	/*
	 * evaluate the left hand side
	 */
	trace(("join::evaluate()\n{\n"/*}*/));
	assert(this->nchild == 2);
	v1 = rpt_expr_evaluate(this->child[0], 1);
	if (v1->method->type == rpt_value_type_error)
	{
		trace((/*{*/"}\n"));
		return v1;
	}
	assert(v1->method->type != rpt_value_type_reference);

	/*
	 * evaluate the right hand side
	 */
	v2 = rpt_expr_evaluate(this->child[1], 1);
	if (v2->method->type == rpt_value_type_error)
	{
		rpt_value_free(v1);
		trace((/*{*/"}\n"));
		return v2;
	}
	assert(v2->method->type != rpt_value_type_reference);

	/*
	 * you can join almost anything to a list
	 */
	if (v1->method->type == rpt_value_type_list)
	{
		long		n;
		long		j;

		result = rpt_value_list();
		n = rpt_value_list_length(v1);
		for (j = 0; j < n; ++j)
		{
			rpt_value_list_append
			(
				result,
				rpt_value_list_nth(v1, j)
			);
		}

		if (v2->method->type == rpt_value_type_list)
		{
			n = rpt_value_list_length(v2);
			for (j = 0; j < n; ++j)
			{
				rpt_value_list_append
				(
					result,
					rpt_value_list_nth(v2, j)
				);
			}
		}
		else
			rpt_value_list_append(result, v2);
	}
	else if (v2->method->type == rpt_value_type_list)
	{
		long		n;
		long		j;

		result = rpt_value_list();
		rpt_value_list_append(result, v1);
		n = rpt_value_list_length(v2);
		for (j = 0; j < n; ++j)
		{
			rpt_value_list_append
			(
				result,
				rpt_value_list_nth(v2, j)
			);
		}
	}
	else
	{
		rpt_value_ty	*v1s;
		rpt_value_ty	*v2s;

		/*
		 * must be a string join
		 */
		v1s = rpt_value_stringize(v1);
		v2s = rpt_value_stringize(v2);
		if
		(
			v1s->method->type == rpt_value_type_string
		&&
			v2s->method->type == rpt_value_type_string
		)
		{
			s =
				str_catenate
				(
					rpt_value_string_query(v1s),
					rpt_value_string_query(v2s)
				);
			result = rpt_value_string(s);
			str_free(s);
		}
		else
		{
			scp = sub_context_new();
			sub_var_set_charstar(scp, "Name1", v1s->method->name);
			sub_var_set_charstar(scp, "Name2", v2s->method->name);
			s =
				subst_intl
				(
					scp,
					i18n("illegal join ($name1 ## $name2)")
				);
			sub_context_delete(scp);
			result = rpt_value_error(this->pos, s);
			str_free(s);
		}
		rpt_value_free(v1s);
		rpt_value_free(v2s);
	}

	/*
	 * clean up and go home
	 */
	rpt_value_free(v1);
	rpt_value_free(v2);
	trace(("return %08lX;\n", (long)result));
	trace((/*{*/"}\n"));
	return result;
}


static rpt_expr_method_ty join_method =
{
	sizeof(rpt_expr_ty),
	"join",
	0, /* construct */
	0, /* destruct */
	join_evaluate,
	0, /* lvalue */
};


rpt_expr_ty *
rpt_expr_join(a, b)
	rpt_expr_ty	*a;
	rpt_expr_ty	*b;
{
	rpt_expr_ty	*this;

	this = rpt_expr_alloc(&join_method);
	rpt_expr_append(this, a);
	rpt_expr_append(this, b);
	return this;
}