/*
 *	PROGRAM:	JRD Command Oriented Query Language
 *	MODULE:		compile.c
 *	DESCRIPTION:	Compile expanded statement into executable things
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 */

#include "firebird.h"
#include <string.h>
#include "../qli/dtr.h"
#include "../qli/compile.h"
#include "../qli/exe.h"
#include "../qli/report.h"
#include "../jrd/intl.h"
#include "../qli/all_proto.h"
#include "../qli/compi_proto.h"
#include "../qli/err_proto.h"
#include "../qli/forma_proto.h"
#include "../qli/meta_proto.h"
#include "../jrd/dsc_proto.h"

#define PROMPT_LENGTH	80

static QLI_NOD compile_any(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_assignment(QLI_NOD, QLI_REQ, int);
static void compile_context(QLI_NOD, QLI_REQ, int);
static void compile_control_break(BRK, QLI_REQ);
static QLI_NOD compile_edit(QLI_NOD, QLI_REQ);
static QLI_NOD compile_erase(QLI_NOD, QLI_REQ);
static QLI_NOD compile_expression(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_field(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_for(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_function(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_if(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_list_fields(QLI_NOD, QLI_REQ);
static QLI_NOD compile_modify(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_print(QLI_NOD, QLI_REQ);
static QLI_NOD compile_print_list(QLI_NOD, QLI_REQ, LLS *);
static QLI_NOD compile_prompt(QLI_NOD);
static QLI_NOD compile_repeat(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_report(QLI_NOD, QLI_REQ);
static QLI_REQ compile_rse(QLI_NOD, QLI_REQ, int, QLI_MSG *, QLI_MSG *, DBB *);
static QLI_NOD compile_statement(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_statistical(QLI_NOD, QLI_REQ, int);
static QLI_NOD compile_store(QLI_NOD, QLI_REQ, int);
static int computable(QLI_NOD, QLI_REQ);
static void make_descriptor(QLI_NOD, DSC *);
static QLI_MSG make_message(QLI_REQ);
static void make_missing_reference(PAR);
static PAR make_parameter(QLI_MSG, QLI_NOD);
static QLI_NOD make_reference(QLI_NOD, QLI_MSG);
static QLI_REQ make_request(DBB);
static void release_message(QLI_MSG);
static int string_length(DSC *);

static LLS print_items;
static TEXT **print_header;
static BRK report_control_break;


QLI_NOD CMPQ_compile( QLI_NOD node)
{
/**************************************
 *
 *	C M P _ c o m p i l e
 *
 **************************************
 *
 * Functional description
 *	Compile a statement into something executable.
 *
 **************************************/

	print_header = NULL;
	print_items = NULL;
	QLI_requests = NULL;
	compile_statement(node, 0, TRUE);

	if (print_header)
		*print_header = FMT_format(print_items);

	return node;
}


void CMP_alloc_temp( QLI_NOD node)
{
/**************************************
 *
 *	C M P _ a l l o c _ t e m p
 *
 **************************************
 *
 * Functional description
 *	Allocate a data area for a node.
 *
 **************************************/
	STR string;

	if (node->nod_desc.dsc_address)
		return;

	string = (STR) ALLOCDV(type_str, node->nod_desc.dsc_length);
	node->nod_desc.dsc_address = (UCHAR *) string->str_data;
}


int CMP_node_match( QLI_NOD node1, QLI_NOD node2)
{
/**************************************
 *
 *	C M P _ n o d e _ m a t c h
 *
 **************************************
 *
 * Functional description
 *	Compare two nodes for equality of value.
 *
 **************************************/
	QLI_NOD *ptr1, *ptr2, *end;
	MAP map1, map2;
	USHORT l;
	UCHAR *p1, *p2;

	if (!node1 || !node2 || node1->nod_type != node2->nod_type)
		return FALSE;

	switch (node1->nod_type) {
	case nod_field:
		{
			if (node1->nod_arg[e_fld_field] != node2->nod_arg[e_fld_field] ||
				node1->nod_arg[e_fld_context] != node2->nod_arg[e_fld_context]
				|| node1->nod_arg[e_fld_subs] != node2->nod_arg[e_fld_subs])
				return FALSE;
			return TRUE;
		}

	case nod_constant:
		{
			if (node1->nod_desc.dsc_dtype != node2->nod_desc.dsc_dtype ||
				node2->nod_desc.dsc_scale != node2->nod_desc.dsc_scale ||
				node2->nod_desc.dsc_length != node2->nod_desc.dsc_length)
				return FALSE;
			p1 = node1->nod_desc.dsc_address;
			p2 = node2->nod_desc.dsc_address;
			if (l = node1->nod_desc.dsc_length)
				do
					if (*p1++ != *p2++)
						return FALSE;
				while (--l);
			return TRUE;
		}

	case nod_map:
		{
			map1 = (MAP) node1->nod_arg[e_map_map];
			map2 = (MAP) node2->nod_arg[e_map_map];
			return CMP_node_match(map1->map_node, map2->map_node);
		}

	case nod_agg_average:
	case nod_agg_max:
	case nod_agg_min:
	case nod_agg_total:
	case nod_agg_count:
		return CMP_node_match(node1->nod_arg[e_stt_value],
							  node2->nod_arg[e_stt_value]);

	case nod_function:
		if (node1->nod_arg[e_fun_function] != node1->nod_arg[e_fun_function])
			return FALSE;
		return CMP_node_match(node1->nod_arg[e_fun_args],
							  node2->nod_arg[e_fun_args]);
	}

	ptr1 = node1->nod_arg;
	ptr2 = node2->nod_arg;

	for (end = ptr1 + node1->nod_count; ptr1 < end; ptr1++, ptr2++)
		if (!CMP_node_match(*ptr1, *ptr2))
			return FALSE;

	return TRUE;
}


static QLI_NOD compile_any( QLI_NOD node, QLI_REQ old_request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ a n y
 *
 **************************************
 *
 * Functional description
 *	Compile either an ANY or UNIQUE boolean expression.
 *
 **************************************/
	QLI_MSG send, receive, old_send = NULL, old_receive = NULL;
	QLI_REQ request;
	PAR parameter;

	if (old_request) {
		old_send = old_request->req_send;
		old_receive = old_request->req_receive;
	}

	if (request = compile_rse(node->nod_arg[e_any_rse],
							  old_request, FALSE, &send, &receive, 0))
		node->nod_arg[e_any_request] = (QLI_NOD) request;
	else
		request = old_request;

	if (old_request) {
		old_request->req_send = old_send;
		old_request->req_receive = old_receive;
	}

	if ((send != old_send) && !send->msg_parameters) {
		release_message(send);
		send = NULL;
		if (!receive)
			return NULL;
	}

	if (old_request && request->req_database != old_request->req_database)
		IBERROR(357);			// Msg357 relations from multiple databases in single rse 

	if (old_request && (!receive || !receive->msg_parameters)) {
		if (receive)
			release_message(receive);
		receive = NULL;
	}

	if (receive) {
		node->nod_import = parameter = make_parameter(receive, 0);
		parameter->par_desc.dsc_dtype = dtype_short;
		parameter->par_desc.dsc_length = sizeof(SSHORT);
	}

	node->nod_arg[e_any_send] = (QLI_NOD) send;
	node->nod_arg[e_any_receive] = (QLI_NOD) receive;

	return node;
}


static QLI_NOD compile_assignment( QLI_NOD node, QLI_REQ request, int statement_internal)
{
/**************************************
 *
 *	c o m p i l e _ a s s i g n m e n t
 *
 **************************************
 *
 * Functional description:
 *	Compile an assignment statement, passing
 *	it to the database if possible.  Possibility
 *	happens when both sides of the assignment are
 *	computable in the request context.  (Following
 *	the logic of such things, the 'internal' flags
 *	mean external to qli, but internal to jrd.
 *	As is well known, the seat of the soul is the
 *	dbms). 
 *
 **************************************/
	QLI_NOD to, target, from, initial;
	QLI_CTX context;
	USHORT target_internal;

/* Start by assuming that the assignment will ultimately
   take place in the DBMS */

	to = node->nod_arg[e_asn_to];
	to->nod_flags |= NOD_parameter2;
	from = node->nod_arg[e_asn_from];
	from->nod_flags |= NOD_parameter2;

/* If the assignment is to a variable, the assignment is
   completely local */

	if (to->nod_type == nod_variable) {
		statement_internal = FALSE;
		node->nod_flags |= NOD_local;
	}

	target_internal = computable(to, request);
	statement_internal = statement_internal && request && target_internal
		&& computable(from, request);

	node->nod_arg[e_asn_to] = target =
		compile_expression(to, request, target_internal);
	node->nod_arg[e_asn_from] =
		compile_expression(from, request, statement_internal);
	if (initial = node->nod_arg[e_asn_initial])
		node->nod_arg[e_asn_initial] =
			compile_expression(initial, request, FALSE);

	if (statement_internal) {
		node->nod_arg[e_asn_valid] = NULL;	// Memory reclaimed in the main loop 
		node->nod_flags |= NOD_remote;
		node = NULL;
	}
	else {
		if (node->nod_arg[e_asn_valid])
			compile_expression(node->nod_arg[e_asn_valid], request, FALSE);
		if (target->nod_type == nod_field) {
			if (!request) {
				context = (QLI_CTX) target->nod_arg[e_fld_context];
				request = context->ctx_request;
			}
			target->nod_arg[e_fld_reference] =
				make_reference(target, request->req_send);
		}
	}

	return node;
}


static void compile_context( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ c o n t e x t
 *
 **************************************
 *
 * Functional description
 *	Set all of the contexts in a request.
 *	This may require a recursive call.
 *
 **************************************/
	QLI_CTX context, *ctx_ptr, *ctx_end;

	ctx_ptr = (QLI_CTX *) node->nod_arg + e_rse_count;
	ctx_end = ctx_ptr + node->nod_count;

	for (; ctx_ptr < ctx_end; ctx_ptr++) {
		context = *ctx_ptr;
		context->ctx_request = request;
		context->ctx_context = request->req_context++;
		context->ctx_message = request->req_receive;
		if (context->ctx_sub_rse)
			compile_rse(context->ctx_sub_rse, request, internal_flag, 0, 0,
						0);
		if (context->ctx_stream)
			compile_context(context->ctx_stream, request, internal_flag);
	}
}


static void compile_control_break( BRK control, QLI_REQ request)
{
/**************************************
 *
 *	c o m p i l e _ c o n t r o l _ b r e a k
 *
 **************************************
 *
 * Functional description
 *	Compile a control/page/report break.
 *
 **************************************/
	QLI_NOD temp;

	for (; control; control = control->brk_next) {
		report_control_break = control;
		if (control->brk_field)
/*
	control->brk_field  = (SYN) compile_expression (control->brk_field, request, FALSE);
*/
		{
			temp = (QLI_NOD) control->brk_field;;
			temp->nod_flags |= NOD_parameter2;
			temp =  compile_expression((QLI_NOD) control->brk_field, request, FALSE);
			if (temp->nod_type == nod_field)
				temp = temp->nod_arg[e_fld_reference];
			control->brk_field = (SYN) temp;
		}
		if (control->brk_line)
			compile_print_list((QLI_NOD) control->brk_line, request, 0);
		report_control_break = NULL;
	}
}


static QLI_NOD compile_edit( QLI_NOD node, QLI_REQ request)
{
/**************************************
 *
 *	c o m p i l e _ e d i t
 *
 **************************************
 *
 * Functional description
 *	Compile the "edit blob" expression.
 *
 **************************************/
	QLI_NOD value;
	QLI_FLD field;

/* Make sure there is a message.  If there isn't a message, we
   can't find the target database. */

	if (!request)
		BUGCHECK(358);			/* Msg358 can't find database for blob edit */

/* If there is an input blob, get it now. */

	if (value = node->nod_arg[e_edt_input]) {
		field = (QLI_FLD) value->nod_arg[e_fld_field];
		if (value->nod_type != nod_field || field->fld_dtype != dtype_blob)
			IBERROR(356);		// Msg356 EDIT argument must be a blob field 
		node->nod_arg[e_edt_input] =
			compile_expression(value, request, FALSE);
	}

	node->nod_arg[e_edt_dbb] = (QLI_NOD) request->req_database;
	node->nod_desc.dsc_dtype = dtype_blob;
	node->nod_desc.dsc_length = 8;
	node->nod_desc.dsc_address = (UCHAR *) & node->nod_arg[e_edt_id1];

	return node;
}


static QLI_NOD compile_erase( QLI_NOD node, QLI_REQ org_request)
{
/**************************************
 *
 *	c o m p i l e _ e r a s e
 *
 **************************************
 *
 * Functional description
 *	Compile an ERASE statement.  This is so simple that nothing
 *	needs to be done.
 *
 **************************************/
	QLI_REQ request;
	QLI_CTX context;

	context = (QLI_CTX) node->nod_arg[e_era_context];
	request = context->ctx_request;
	node->nod_arg[e_era_request] = (QLI_NOD) request;

	request->req_database->dbb_flags |= DBB_updates;

	if (org_request == request && !request->req_continue)
		return NULL;

	if (!request->req_continue)
		request->req_continue = make_message(request);

	node->nod_arg[e_era_message] = (QLI_NOD) make_message(request);

	return node;
}


static QLI_NOD compile_expression( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ e x p r e s s i o n
 *
 **************************************
 *
 * Functional description
 *	Compile a value.  The value may be used internally as part of
 *	another expression (internal_flag == TRUE) or may be referenced
 *	in the QLI context (internal_flag == FALSE).	
 *
 **************************************/
	QLI_NOD *ptr, *end, value;
	MAP map;
	PAR parm;
	QLI_FLD field;

	switch (node->nod_type) {
	case nod_any:
	case nod_unique:
		return compile_any(node, request, internal_flag);

	case nod_max:
	case nod_min:
	case nod_count:
	case nod_average:
	case nod_total:
	case nod_from:
		node->nod_count = 0;
		return compile_statistical(node, request, internal_flag);

	case nod_rpt_max:
	case nod_rpt_min:
	case nod_rpt_count:
	case nod_rpt_average:
	case nod_rpt_total:
		if (report_control_break)
			LLS_PUSH(node, &report_control_break->brk_statisticals);

	case nod_running_total:
	case nod_running_count:
		node->nod_count = 0;
		if (value = node->nod_arg[e_stt_value]) {
			value->nod_flags |= NOD_parameter2;
			node->nod_arg[e_stt_value] =
				compile_expression(value, request, FALSE);
		}
		make_descriptor(node, &node->nod_desc);
		if (internal_flag) {
			node->nod_export = parm = make_parameter(request->req_send, 0);
			parm->par_desc = node->nod_desc;
			parm->par_value = node;
		}
		else {
			CMP_alloc_temp(node);
			if (request && value && computable(value, request))
				node->nod_arg[e_stt_value] =
					make_reference(value, request->req_receive);
		}
		return node;

	case nod_agg_max:
	case nod_agg_min:
	case nod_agg_count:
	case nod_agg_average:
	case nod_agg_total:
		node->nod_count = 0;
		if (value = node->nod_arg[e_stt_value]) {
			value->nod_flags |= NOD_parameter2;
			node->nod_arg[e_stt_value] =
				compile_expression(value, request, TRUE);
		}
		make_descriptor(node, &node->nod_desc);
		if (!internal_flag && request)
			return make_reference(node, request->req_receive);
		return node;

	case nod_map:
		map = (MAP) node->nod_arg[e_map_map];
		map->map_node = value =
			compile_expression(map->map_node, request, TRUE);
		make_descriptor(value, &node->nod_desc);
		if (!internal_flag && request)
			return make_reference(node, request->req_receive);
		return node;

	case nod_function:
		return compile_function(node, request, internal_flag);

	case nod_eql:
	case nod_neq:
	case nod_gtr:
	case nod_geq:
	case nod_leq:
	case nod_lss:
	case nod_between:
		node->nod_flags |= nod_comparison;

	case nod_list:
	case nod_matches:
	case nod_sleuth:
	case nod_like:
	case nod_containing:
	case nod_starts:
	case nod_missing:
	case nod_and:
	case nod_or:
	case nod_not:
		for (ptr = node->nod_arg, end = ptr + node->nod_count; ptr < end;
			 ptr++) {
			(*ptr)->nod_flags |= NOD_parameter2;
			*ptr = compile_expression(*ptr, request, internal_flag);
		}
		if (node->nod_type == nod_and || node->nod_type == nod_or)
			node->nod_flags |= nod_partial;
		return node;

	case nod_null:
	case nod_add:
	case nod_subtract:
	case nod_multiply:
	case nod_divide:
	case nod_negate:
	case nod_concatenate:
	case nod_substr:
	case nod_user_name:
		if (!internal_flag && request && request->req_receive &&
			computable(node, request)) {
			compile_expression(node, request, TRUE);
			return make_reference(node, request->req_receive);
		}
		for (ptr = node->nod_arg, end = ptr + node->nod_count; ptr < end;
			 ptr++) {
			(*ptr)->nod_flags |= NOD_parameter2;
			*ptr = compile_expression(*ptr, request, internal_flag);
		}
		make_descriptor(node, &node->nod_desc);
		if (!internal_flag) {
			node->nod_flags |= NOD_local;
			CMP_alloc_temp(node);
		}
		return node;

	case nod_format:
		value = node->nod_arg[e_fmt_value];
		node->nod_arg[e_fmt_value] =
			compile_expression(value, request, FALSE);
		node->nod_desc.dsc_length = FMT_expression(node);
		node->nod_desc.dsc_dtype = dtype_text;
		CMP_alloc_temp(node);
		if (!internal_flag)
			node->nod_flags |= NOD_local;
		return node;

	case nod_constant:
		if (!internal_flag)
			node->nod_flags |= NOD_local;
		return node;

	case nod_edit_blob:
		compile_edit(node, request);
		return node;

	case nod_prompt:
		node->nod_count = 0;
		compile_prompt(node);
		if (internal_flag) {
			node->nod_export = parm = make_parameter(request->req_send, node);
			parm->par_value = node;
			if (field = (QLI_FLD) node->nod_arg[e_prm_field]) {
				parm->par_desc.dsc_dtype = field->fld_dtype;
				parm->par_desc.dsc_length = field->fld_length;
				parm->par_desc.dsc_scale = field->fld_scale;
				parm->par_desc.dsc_sub_type = field->fld_sub_type;
				if (parm->par_desc.dsc_dtype == dtype_text) {
					parm->par_desc.dsc_dtype = dtype_varying;
					parm->par_desc.dsc_length += sizeof(SSHORT);
				}
			}
			else
				parm->par_desc = node->nod_desc;
		}
		return node;

	case nod_field:
		if (value = node->nod_arg[e_fld_subs])
			compile_expression(value, request, TRUE);
		return compile_field(node, request, internal_flag);

	case nod_variable:
		field = (QLI_FLD) node->nod_arg[e_fld_field];
		node->nod_desc.dsc_address = field->fld_data;
	case nod_upcase:
		value = node->nod_arg[0];
		node->nod_arg[0] = compile_field(value, request, internal_flag);
		return node;

	default:
		BUGCHECK(359);			/* Msg359 compile_expression: not yet implemented */
		return NULL;
	}
}


static QLI_NOD compile_field( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ f i e l d
 *
 **************************************
 *
 * Functional description
 *	Compile a field reference.
 *
 **************************************/
	QLI_CTX context;
	PAR parm;
	QLI_MSG message;
	QLI_FLD field;

// Pick up field characteristics 

	node->nod_count = 0;
	field = (QLI_FLD) node->nod_arg[e_fld_field];
	context = (QLI_CTX) node->nod_arg[e_fld_context];
	if ((field->fld_flags & FLD_array) && !node->nod_arg[e_fld_subs]) {
		node->nod_desc.dsc_dtype = dtype_quad;
		node->nod_desc.dsc_length = 8;
		node->nod_desc.dsc_scale = 0;
		node->nod_desc.dsc_sub_type = 0;
	}
	else {
		node->nod_desc.dsc_dtype = field->fld_dtype;
		node->nod_desc.dsc_length = field->fld_length;
		node->nod_desc.dsc_scale = field->fld_scale;
		node->nod_desc.dsc_sub_type = field->fld_sub_type;
	}
	node->nod_flags |= NOD_parameter2;

/* If the reference is external, or the value is computable in the
   current request, there is nothing to do.  If the value is not computable,
   make up a parameter to send the value into the request. */

	if (internal_flag) {
		if (computable(node, request))
			return node;
		node->nod_export = parm = make_parameter(request->req_send, node);
		parm->par_desc = node->nod_desc;
		parm->par_value = node;
		if (!(message = context->ctx_message))
			message = request->req_receive;
		node->nod_arg[e_fld_reference] = make_reference(node, message);
		return node;
	}

	if (!(message = context->ctx_message) && request)
		message = request->req_receive;

	node->nod_arg[e_fld_reference] = make_reference(node, message);
	return node;
}


static QLI_NOD compile_for( QLI_NOD node, QLI_REQ old_request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ f o r
 *
 **************************************
 *
 * Functional description
 *	Compile a FOR loop.  If the loop can be done as part of the parent
 *	request, dandy.
 *
 **************************************/
	QLI_MSG send, receive, old_send = NULL, old_receive = NULL;
	QLI_REQ request;
	PAR parameter;

/* Compile rse.  This will set up both send and receive message.  If the
   messages aren't needed, we can release them later. */

	if (old_request) {
		old_send = old_request->req_send;
		old_receive = old_request->req_receive;
	}

	if (request = compile_rse(node->nod_arg[e_for_rse],
							  old_request, FALSE, &send, &receive, 0))
		node->nod_arg[e_for_request] = (QLI_NOD) request;
	else
		request = old_request;

/* If nothing is required for sub-statement, and no data is required in
   either direction, we don't need  to execute the statement. */

	if (!compile_statement
		(node->nod_arg[e_for_statement], request, internal_flag)
		&& !receive->msg_parameters) {
		release_message(receive);
		receive = NULL;
	}

	if (old_request) {
		old_request->req_send = old_send;
		old_request->req_receive = old_receive;
	}

	if ((send != old_send) && !send->msg_parameters) {
		release_message(send);
		send = NULL;
		if (!receive)
			return NULL;
	}

	if (receive) {
		parameter = make_parameter(receive, 0);
		node->nod_arg[e_for_eof] = (QLI_NOD) parameter;
		parameter->par_desc.dsc_dtype = dtype_short;
		parameter->par_desc.dsc_length = sizeof(SSHORT);
	}

	node->nod_arg[e_for_send] = (QLI_NOD) send;
	node->nod_arg[e_for_receive] = (QLI_NOD) receive;

	return node;
}


static QLI_NOD compile_function( QLI_NOD node, QLI_REQ old_request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ f u n c t i o n
 *
 **************************************
 *
 * Functional description
 *	Compile a database function reference.
 *
 **************************************/
	QLI_NOD *ptr, *end, list;
	FUN function;
	QLI_MSG send, receive, old_send = NULL, old_receive = NULL;
	QLI_REQ request;
	PAR parameter;

	function = (FUN) node->nod_arg[e_fun_function];
	node->nod_count = 0;
	send = NULL;

	if (!internal_flag)
		old_request = NULL;

	if (old_request) {
		old_send = old_request->req_send;
		old_receive = old_request->req_receive;
	}

	if (!old_request || old_request->req_database != function->fun_database) {
		request = make_request(function->fun_database);
		node->nod_arg[e_fun_request] = (QLI_NOD) request;
		request->req_send = send = make_message(request);
		request->req_receive = receive = make_message(request);
	}
	else
		request = old_request;

/* If there is a value, compile it here */

	if (!internal_flag) {
		node->nod_import = parameter =
			make_parameter(request->req_receive, 0);
		make_descriptor(node, &parameter->par_desc);
	}

	list = node->nod_arg[e_fun_args];

	for (ptr = list->nod_arg, end = ptr + list->nod_count; ptr < end; ptr++)
		compile_expression(*ptr, request, TRUE);

	if (old_request) {
		old_request->req_send = old_send;
		old_request->req_receive = old_receive;
	}

	if (!internal_flag && request == old_request && computable(node, request)) {
		make_descriptor(node, &node->nod_desc);
		return make_reference(node, request->req_receive);
	}

	if (send && (send != old_send) && !send->msg_parameters) {
		release_message(send);
		send = NULL;
	}

	node->nod_arg[e_fun_receive] = (QLI_NOD) receive;
	node->nod_arg[e_fun_send] = (QLI_NOD) send;

	return node;
}


static QLI_NOD compile_if( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ i f
 *
 **************************************
 *
 * Functional description
 *	Compile an IF statement.  Determine whether the
 *	statement is going to be executed in QLI or database
 *	context.  Try to make sure that the whole thing is
 *	executed one place or the other.
 *
 **************************************/
	QLI_NOD sub;

/* If the statement can't be executed in database context,
   make sure it gets executed locally */

	if (!internal_flag || !computable(node, request)) {
		internal_flag = FALSE;
		node->nod_flags |= NOD_local;
		request = NULL;
	}

	sub = node->nod_arg[e_if_boolean];
	compile_expression(sub, request, internal_flag);
	compile_statement(node->nod_arg[e_if_true], request, internal_flag);

	if (sub = node->nod_arg[e_if_false])
		compile_statement(sub, request, internal_flag);

	if (internal_flag)
		return NULL;

	return node;
}


static QLI_NOD compile_list_fields( QLI_NOD node, QLI_REQ request)
{
/**************************************
 *
 *	c o m p i l e _ l i s t _ f i e l d s
 *
 **************************************
 *
 * Functional description
 *	Compile a print node.
 *
 **************************************/
	QLI_NOD list;

	list = node->nod_arg[e_prt_list];
	compile_print_list(list, request, 0);
	node->nod_arg[e_prt_list] = FMT_list(list);
	node->nod_type = nod_print;

	return node;
}


static QLI_NOD compile_modify( QLI_NOD node, QLI_REQ org_request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ m o d i f y
 *
 **************************************
 *
 * Functional description
 *	Compile a modify statement.
 *
 **************************************/
	QLI_REQ request;
	QLI_CTX context;
	QLI_MSG send, old_send;
	QLI_NOD *ptr;
	USHORT i;

/* If this is a different request from the current one, this will require an
   optional action and a "continue" mesasge */

	ptr = node->nod_arg + e_mod_count;
	context = (QLI_CTX) * ptr;
	request = context->ctx_source->ctx_request;
	node->nod_arg[e_mod_request] = (QLI_NOD) request;

	if ((request != org_request || !internal_flag) && !request->req_continue)
		request->req_continue = make_message(request);

	old_send = request->req_send;
	request->req_send = send = make_message(request);

	for (i = 0; i < node->nod_count; i++) {
		context = (QLI_CTX) * ptr++;
		context->ctx_request = request;
		context->ctx_context = request->req_context++;
		context->ctx_message = send;
	}

/* If nothing is required for sub-statement, and no data is required in
   either direction, we don't need  to execute the statement. */

	if (internal_flag)
		internal_flag = computable(node->nod_arg[e_mod_statement], request);

	if (!compile_statement
		(node->nod_arg[e_mod_statement], request, internal_flag)
		&& (send != old_send) && !send->msg_parameters) {
		node->nod_flags |= NOD_remote;
		release_message(send);
		send = NULL;
	}

	node->nod_arg[e_mod_send] = (QLI_NOD) send;
	request->req_send = old_send;
	request->req_database->dbb_flags |= DBB_updates;

	if (internal_flag)
		return NULL;

	return node;
}


static QLI_NOD compile_print( QLI_NOD node, QLI_REQ request)
{
/**************************************
 *
 *	c o m p i l e _ p r i n t
 *
 **************************************
 *
 * Functional description
 *	Compile a print node.
 *
 **************************************/

	if (!print_header)
		print_header = (TEXT **) & node->nod_arg[e_prt_header];

	compile_print_list(node->nod_arg[e_prt_list], request, &print_items);

	return node;
}


static QLI_NOD compile_print_list( QLI_NOD list, QLI_REQ request, LLS * stack)
{
/**************************************
 *
 *	c o m p i l e _ p r i n t _ l i s t
 *
 **************************************
 *
 * Functional description
 *	Compile a print node.
 *
 **************************************/
	QLI_NOD *ptr, *end, value;
	ITM item;

	for (ptr = list->nod_arg, end = ptr + list->nod_count; ptr < end; ptr++) {
		item = (ITM) * ptr;
		if (stack)
			LLS_PUSH(item, stack);
		if (item->itm_type == item_value) {
			value = item->itm_value;
			value->nod_flags |= NOD_parameter2;
			item->itm_value = compile_expression(value, request, FALSE);
			if (item->itm_value->nod_type == nod_field)
				item->itm_value = item->itm_value->nod_arg[e_fld_reference];
			if (!value->nod_desc.dsc_dtype)
				make_descriptor(value, &value->nod_desc);
		}
	}

	return list;
}


static QLI_NOD compile_prompt( QLI_NOD node)
{
/**************************************
 *
 *	c o m p i l e _ p r o m p t
 *
 **************************************
 *
 * Functional description
 *	Set up a prompt expression for execution.
 *
 **************************************/
	STR string;
	QLI_FLD field;
	USHORT prompt_length;

// Make up a plausible prompt length 

	if (!(field = (QLI_FLD) node->nod_arg[e_prm_field]))
		prompt_length = PROMPT_LENGTH;
	else
		switch (field->fld_dtype) {
		case dtype_text:
			prompt_length = field->fld_length;
			break;

		case dtype_varying:
			prompt_length = field->fld_length - sizeof(SSHORT);
			break;

		case dtype_short:
			prompt_length = 8;
			break;

		case dtype_long:
		case dtype_real:
			prompt_length = 15;
			break;

		default:
			prompt_length = 30;
			break;
		}

/* Allocate string buffer to hold data, a two byte count, 
  a possible carriage return, and a null */

	prompt_length += 2 + sizeof(SSHORT);
	string = (STR) ALLOCDV(type_str, prompt_length);
	node->nod_arg[e_prm_string] = (QLI_NOD) string;
	node->nod_desc.dsc_dtype = dtype_varying;
	node->nod_desc.dsc_length = prompt_length;
	node->nod_desc.dsc_address = (UCHAR *) string->str_data;

	return node;
}


static QLI_NOD compile_repeat( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ r e p e a t
 *
 **************************************
 *
 * Functional description
 *	Compile a REPEAT statement.
 *
 **************************************/

	compile_expression(node->nod_arg[e_rpt_value], request, FALSE);
	compile_statement(node->nod_arg[e_rpt_statement], 0, internal_flag);

	return node;
}


static QLI_NOD compile_report( QLI_NOD node, QLI_REQ request)
{
/**************************************
 *
 *	c o m p i l e _ r e p o r t
 *
 **************************************
 *
 * Functional description
 *	Compile the body of a report specification.
 *
 **************************************/
	RPT report;
	BRK control, temp;
	QLI_NOD list;

	report = (RPT) node->nod_arg[e_prt_list];

	if (control = report->rpt_top_rpt)
		compile_control_break(control, request);

	if (control = report->rpt_top_page)
		compile_control_break(control, request);

	if (control = report->rpt_top_breaks)
		compile_control_break(control, request);

	if (list = report->rpt_detail_line)
		compile_print_list(list, request, 0);

	if (control = report->rpt_bottom_breaks) {
		compile_control_break(control, request);
		report->rpt_bottom_breaks = NULL;
		while (control) {
			temp = control;
			control = control->brk_next;
			temp->brk_next = report->rpt_bottom_breaks;
			report->rpt_bottom_breaks = temp;
		}
	}

	if (control = report->rpt_bottom_page)
		compile_control_break(control, request);

	if (control = report->rpt_bottom_rpt)
		compile_control_break(control, request);

	FMT_report(report);

	return node;
}


static QLI_REQ compile_rse(
					   QLI_NOD node,
					   QLI_REQ old_request,
					   int internal_flag,
					   QLI_MSG * send, QLI_MSG * receive, DBB * database)
{
/**************************************
 *
 *	c o m p i l e _ r s e
 *
 **************************************
 *
 * Functional description
 *	Compile a record selection expression.  If it can't be processed
 *	as part of an existing parent request, make up a new request.  If
 *	data must be sent to start the loop, generate a send message.  Set
 *	up for a receive message as well.
 *
 **************************************/
	QLI_NOD list, *ptr, *end;
	QLI_REQ request, original_request;
	QLI_CTX context, *ctx_ptr, *ctx_end;
	QLI_REL relation;
	DBB local_dbb;

	original_request = old_request;

	if (!database) {
		local_dbb = NULL;
		database = &local_dbb;
	}

// Loop thru relations to make sure only a single database is presented 

	ctx_ptr = (QLI_CTX *) node->nod_arg + e_rse_count;
	ctx_end = ctx_ptr + node->nod_count;

	for (; ctx_ptr < ctx_end; ctx_ptr++) {
		context = *ctx_ptr;
		if (context->ctx_stream) {
			if (request =
				compile_rse(context->ctx_stream, old_request, internal_flag,
							send, receive, database))
				old_request = request;
		}
		else {
			relation = context->ctx_relation;
			if (!*database)
				*database = relation->rel_database;
			else if (*database != relation->rel_database)
				IBERROR(357);	// Msg357 relations from multiple databases in single rse 
		}
	}

	if (!old_request || old_request->req_database != *database)
		request = make_request(*database);
	else
		request = old_request;

	if (send) {
		if (old_request && request == old_request &&
			!(old_request->req_flags & REQ_rse_compiled))
			*send = request->req_send;
		else
			request->req_send = *send = make_message(request);
		request->req_receive = *receive = make_message(request);
	}

	compile_context(node, request, internal_flag);

// Process various clauses 

	if (node->nod_arg[e_rse_first])
		compile_expression(node->nod_arg[e_rse_first], request, TRUE);

	if (node->nod_arg[e_rse_boolean])
		compile_expression(node->nod_arg[e_rse_boolean], request, TRUE);

	if (list = node->nod_arg[e_rse_sort])
		for (ptr = list->nod_arg, end = ptr + list->nod_count * 2; ptr < end;
			 ptr += 2)
			compile_expression(*ptr, request, TRUE);

	if (list = node->nod_arg[e_rse_reduced])
		for (ptr = list->nod_arg, end = ptr + list->nod_count * 2; ptr < end;
			 ptr += 2)
			compile_expression(*ptr, request, TRUE);

	if (list = node->nod_arg[e_rse_group_by])
		for (ptr = list->nod_arg, end = ptr + list->nod_count; ptr < end;
			 ptr++)
			compile_expression(*ptr, request, TRUE);

	if (node->nod_arg[e_rse_having])
		compile_expression(node->nod_arg[e_rse_having], request, TRUE);

/* If we didn't allocate a new request block, say so by returning NULL */

	if (request == original_request)
		return NULL;

	request->req_flags |= REQ_rse_compiled;

	return request;
}


static QLI_NOD compile_statement( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ s t a t e m e n t
 *
 **************************************
 *
 * Functional description
 *	Compile a statement.  Actually, just dispatch, passing along
 *	the parent request.
 *
 **************************************/
	QLI_NOD result, *ptr, *end;

	switch (node->nod_type) {
	case nod_assign:
		return compile_assignment(node, request, internal_flag);

	case nod_erase:
		return compile_erase(node, request);

	case nod_commit_retaining:
		return node;

	case nod_for:
	case nod_report_loop:
		return compile_for(node, request, internal_flag);

	case nod_list:
		result = NULL;
		for (ptr = node->nod_arg, end = ptr + node->nod_count; ptr < end;
			 ptr++)
			if (compile_statement(*ptr, request, internal_flag))
				result = node;
		return result;

	case nod_modify:
		return compile_modify(node, request, internal_flag);

	case nod_output:
		compile_expression(node->nod_arg[e_out_file], request, FALSE);
		compile_statement(node->nod_arg[e_out_statement], request, FALSE);
		return node;

	case nod_print:
		return compile_print(node, request);

	case nod_list_fields:
		return compile_list_fields(node, request);

	case nod_repeat:
		return compile_repeat(node, request, internal_flag);

	case nod_report:
		return compile_report(node, request);

	case nod_store:
		return compile_store(node, request, internal_flag);

	case nod_if:
		return compile_if(node, request, internal_flag);

	case nod_abort:
		if (node->nod_count)
			compile_expression(node->nod_arg[0], 0, FALSE);
		return node;

	default:
		BUGCHECK(360);			/* Msg360 not yet implemented (compile_statement) */
		return NULL;
	}
}


static QLI_NOD compile_statistical( QLI_NOD node, QLI_REQ old_request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ s t a t i s t i c a l
 *
 **************************************
 *
 * Functional description
 *	Compile a statistical expression.  The expression may or may not
 *	request a separate request.
 *
 **************************************/
	QLI_NOD value;
	QLI_MSG send, receive, old_send = NULL, old_receive = NULL;
	QLI_REQ request;
	PAR parameter;

/* If a default value is present, compile it outside the context of
   the rse. */

	if (value = node->nod_arg[e_stt_default])
		compile_expression(value, old_request, TRUE);

/* Compile rse.  This will set up both send and receive message.  If the
   messages aren't needed, we can release them later. */

	if (!internal_flag)
		old_request = NULL;

	if (old_request) {
		old_send = old_request->req_send;
		old_receive = old_request->req_receive;
	}

	if (request = compile_rse(node->nod_arg[e_stt_rse],
							  old_request, internal_flag, &send, &receive, 0))
		node->nod_arg[e_stt_request] = (QLI_NOD) request;
	else
		request = old_request;

/* If there is a value, compile it here */

	if (!internal_flag) {
		node->nod_import = parameter =
			make_parameter(request->req_receive, 0);
		make_descriptor(node, &parameter->par_desc);
	}

	if (value = node->nod_arg[e_stt_value])
		compile_expression(value, request, TRUE);

	if (old_request) {
		old_request->req_send = old_send;
		old_request->req_receive = old_receive;
	}

	if (!internal_flag && request == old_request && computable(node, request)) {
		make_descriptor(node, &node->nod_desc);
		return make_reference(node, request->req_receive);
	}

	if ((send != old_send) && !send->msg_parameters) {
		release_message(send);
		send = NULL;
	}

	node->nod_arg[e_stt_receive] = (QLI_NOD) receive;
	node->nod_arg[e_stt_send] = (QLI_NOD) send;

	return node;
}


static QLI_NOD compile_store( QLI_NOD node, QLI_REQ request, int internal_flag)
{
/**************************************
 *
 *	c o m p i l e _ s t o r e
 *
 **************************************
 *
 * Functional description
 *	Compile a STORE statement.
 *
 **************************************/
	QLI_CTX context;
	QLI_REL relation;
	QLI_MSG send;

// Find or make up request for statement 

	context = (QLI_CTX) node->nod_arg[e_sto_context];
	relation = context->ctx_relation;

	if (!request || request->req_database != relation->rel_database) {
		request = make_request(relation->rel_database);
		node->nod_arg[e_sto_request] = (QLI_NOD) request;
	}

	request->req_database->dbb_flags |= DBB_updates;

	context->ctx_request = request;
	context->ctx_context = request->req_context++;
	context->ctx_message = request->req_send = send = make_message(request);

/* If nothing is required for sub-statement, and no data is required in
   either direction, we don't need to execute the statement. */

	if (internal_flag)
		internal_flag = computable(node->nod_arg[e_sto_statement], request);

	if (!compile_statement
		(node->nod_arg[e_sto_statement], request, internal_flag)
		&& !send->msg_parameters) {
		node->nod_flags |= NOD_remote;
		release_message(send);
		return NULL;
	}

	node->nod_arg[e_sto_send] = (QLI_NOD) send;

	return node;
}


static int computable( QLI_NOD node, QLI_REQ request)
{
/**************************************
 *
 *	c o m p u t a b l e
 *
 **************************************
 *
 * Functional description
 *	Check to see if a value is computable within the context of a
 *	given request.
 *
 **************************************/
	QLI_NOD *ptr, *end, sub;
	QLI_CTX context;
	MAP map;

	switch (node->nod_type) {
	case nod_max:
	case nod_min:
	case nod_count:
	case nod_average:
	case nod_total:
	case nod_from:
		if ((sub = node->nod_arg[e_stt_rse]) && !computable(sub, request))
			return FALSE;
		if ((sub = node->nod_arg[e_stt_value]) && !computable(sub, request))
			return FALSE;
		if ((sub = node->nod_arg[e_stt_default]) && !computable(sub, request))
			return FALSE;
		return TRUE;

	case nod_rse:
		if (!request)
			return FALSE;
		if ((sub = node->nod_arg[e_rse_first]) && !computable(sub, request))
			return FALSE;
		for (ptr = node->nod_arg + e_rse_count, end = ptr + node->nod_count;
			 ptr < end; ptr++) {
			context = (QLI_CTX) * ptr;
			if (context->ctx_stream) {
				if (!computable(context->ctx_stream, request))
					return FALSE;
			}
			else if (context->ctx_relation->rel_database !=
					 request->req_database) return FALSE;
			context->ctx_request = request;
		}
		if ((sub = node->nod_arg[e_rse_boolean]) && !computable(sub, request))
			return FALSE;
		return TRUE;

	case nod_field:
		if (sub = node->nod_arg[e_fld_subs])
			for (ptr = sub->nod_arg, end = ptr + sub->nod_count; ptr < end;
				 ptr++)
				if (*ptr && !computable(*ptr, request))
					return FALSE;
		context = (QLI_CTX) node->nod_arg[e_fld_context];
		return (request == context->ctx_request);

	case nod_map:
		map = (MAP) node->nod_arg[e_map_map];
		return computable(map->map_node, request);

	case nod_print:
	case nod_report:
	case nod_abort:
	case nod_repeat:
	case nod_commit_retaining:

	case nod_rpt_average:
	case nod_rpt_max:
	case nod_rpt_min:
	case nod_rpt_total:
	case nod_rpt_count:
	case nod_running_total:
	case nod_running_count:
	case nod_edit_blob:
	case nod_prompt:
	case nod_variable:
	case nod_format:
		return FALSE;

	case nod_null:
	case nod_constant:
	case nod_user_name:
		return TRUE;

	case nod_for:
		if ((QLI_REQ) node->nod_arg[e_for_request] != request)
			return FALSE;
		if (!computable(node->nod_arg[e_for_rse], request) ||
			!computable(node->nod_arg[e_for_statement], request))
			return FALSE;
		return TRUE;

	case nod_store:
		if ((QLI_REQ) node->nod_arg[e_sto_request] != request)
			return FALSE;
		return computable(node->nod_arg[e_sto_statement], request);

	case nod_modify:
		context = (QLI_CTX) node->nod_arg[e_mod_count];
		if (context->ctx_source->ctx_request != request)
			return FALSE;
		return computable(node->nod_arg[e_mod_statement], request);

	case nod_erase:
		context = (QLI_CTX) node->nod_arg[e_era_context];
		if (context->ctx_source->ctx_request != request)
			return FALSE;
		return TRUE;

	case nod_unique:
	case nod_any:
		if (node->nod_arg[e_any_request] != (QLI_NOD) request)
			return FALSE;
		return (computable(node->nod_arg[e_any_rse], request));

	case nod_agg_max:
	case nod_agg_min:
	case nod_agg_count:
	case nod_agg_average:
	case nod_agg_total:
		if (sub = node->nod_arg[e_stt_value])
			return (computable(sub, request));

	case nod_assign:
		if (node->nod_arg[e_asn_valid]) {
			sub = node->nod_arg[e_asn_from];
			if (sub->nod_type == nod_prompt)
				/* Try to do validation in QLI as soon as 
				   the user responds to the prompt */
				return FALSE;
		}
	case nod_list:
	case nod_if:

	case nod_eql:
	case nod_neq:
	case nod_gtr:
	case nod_geq:
	case nod_leq:
	case nod_lss:
	case nod_between:
	case nod_matches:
	case nod_sleuth:
	case nod_like:
	case nod_containing:
	case nod_starts:
	case nod_missing:
	case nod_and:
	case nod_or:
	case nod_not:
	case nod_add:
	case nod_subtract:
	case nod_multiply:
	case nod_divide:
	case nod_negate:
	case nod_concatenate:
	case nod_function:
	case nod_substr:
		for (ptr = node->nod_arg, end = ptr + node->nod_count; ptr < end;
			 ptr++)
			if (*ptr && !computable(*ptr, request))
				return FALSE;
		return TRUE;

	default:
		BUGCHECK(361);			/* Msg361 computable: not yet implemented */
		return FALSE;
	}
}


static void make_descriptor( QLI_NOD node, DSC * desc)
{
/**************************************
 *
 *	m a k e _ d e s c r i p t o r
 *
 **************************************
 *
 * Functional description
 *	Fill out a descriptor based on an expression.
 *
 **************************************/
	DSC desc1, desc2;
	QLI_FLD field;
	PAR parameter;
	MAP map;
	FUN function;
	USHORT dtype;

	desc1.dsc_dtype = 0;
	desc1.dsc_scale = 0;
	desc1.dsc_length = 0;
	desc1.dsc_sub_type = 0;
	desc1.dsc_address = NULL;
	desc1.dsc_flags = 0;
	desc2 = desc1;

	switch (node->nod_type) {
	case nod_field:
	case nod_variable:
		field = (QLI_FLD) node->nod_arg[e_fld_field];
		desc->dsc_dtype = field->fld_dtype;
		desc->dsc_length = field->fld_length;
		desc->dsc_scale = field->fld_scale;
		desc->dsc_sub_type = field->fld_sub_type;
		return;

	case nod_reference:
		parameter = node->nod_import;
		*desc = parameter->par_desc;
		return;

	case nod_map:
		map = (MAP) node->nod_arg[e_map_map];
		make_descriptor(map->map_node, desc);
		return;

	case nod_function:
		function = (FUN) node->nod_arg[e_fun_function];
		*desc = function->fun_return;
		return;

	case nod_constant:
	case nod_prompt:
	case nod_format:
		*desc = node->nod_desc;
		return;

	case nod_concatenate:
		make_descriptor(node->nod_arg[0], &desc1);
		make_descriptor(node->nod_arg[1], &desc2);
		desc->dsc_scale = 0;
		desc->dsc_dtype = dtype_varying;
		desc->dsc_length = sizeof(USHORT) +
			string_length(&desc1) + string_length(&desc2);
		if (desc1.dsc_dtype <= dtype_any_text)
			desc->dsc_sub_type = desc1.dsc_sub_type;
		else
			desc->dsc_sub_type = ttype_ascii;
		return;

	case nod_add:
	case nod_subtract:
		make_descriptor(node->nod_arg[0], &desc1);
		make_descriptor(node->nod_arg[1], &desc2);
		if ((desc1.dsc_dtype == dtype_text && desc1.dsc_length >= 9) ||
			(desc2.dsc_dtype == dtype_text && desc2.dsc_length >= 9))
			dtype = dtype_double;
		else
			dtype = MAX(desc1.dsc_dtype, desc2.dsc_dtype);
		switch (dtype) {
		case dtype_sql_time:
		case dtype_sql_date:
		case dtype_timestamp:
			node->nod_flags |= nod_date;
			if (node->nod_type == nod_add) {
				desc->dsc_dtype = dtype;
				desc->dsc_length = (dtype == dtype_timestamp) ? 8 : 4;
				break;
			}

		case dtype_varying:
		case dtype_cstring:
		case dtype_text:
		case dtype_double:
		case dtype_real:
		case dtype_long:
			desc->dsc_dtype = dtype_double;
			desc->dsc_length = sizeof(double);
			break;

		default:
			desc->dsc_dtype = dtype_long;
			desc->dsc_length = sizeof(SLONG);
			desc->dsc_scale = MIN(desc1.dsc_scale, desc2.dsc_scale);
			break;
		}
		return;

	case nod_multiply:
		make_descriptor(node->nod_arg[0], &desc1);
		make_descriptor(node->nod_arg[1], &desc2);
		if ((desc1.dsc_dtype == dtype_text && desc1.dsc_length >= 9) ||
			(desc2.dsc_dtype == dtype_text && desc2.dsc_length >= 9))
			dtype = dtype_double;
		else
			dtype = MAX(desc1.dsc_dtype, desc2.dsc_dtype);
		switch (dtype) {
		case dtype_varying:
		case dtype_cstring:
		case dtype_text:
		case dtype_real:
		case dtype_double:
		case dtype_long:
			desc->dsc_dtype = dtype_double;
			desc->dsc_length = sizeof(double);
			break;

		default:
			desc->dsc_dtype = dtype_long;
			desc->dsc_length = sizeof(SLONG);
			desc->dsc_scale = desc1.dsc_scale + desc2.dsc_scale;
			break;
		}
		return;

	case nod_agg_average:
	case nod_agg_max:
	case nod_agg_min:
	case nod_agg_total:

	case nod_average:
	case nod_max:
	case nod_min:
	case nod_total:
	case nod_from:

	case nod_rpt_average:
	case nod_rpt_max:
	case nod_rpt_min:
	case nod_rpt_total:
	case nod_running_total:
		make_descriptor(node->nod_arg[e_stt_value], desc);
		if (desc->dsc_dtype == dtype_short) {
			desc->dsc_dtype = dtype_long;
			desc->dsc_length = sizeof(SLONG);
		}
		else if (desc->dsc_dtype == dtype_real) {
			desc->dsc_dtype = dtype_double;
			desc->dsc_length = sizeof(double);
		}
		return;

	case nod_null:
		desc->dsc_dtype = dtype_long;
		desc->dsc_length = sizeof(SLONG);
		desc->dsc_missing = DSC_missing;
		return;

	case nod_count:
	case nod_agg_count:
	case nod_running_count:
	case nod_rpt_count:
		desc->dsc_dtype = dtype_long;
		desc->dsc_length = sizeof(SLONG);
		return;

	case nod_divide:
		desc->dsc_dtype = dtype_double;
		desc->dsc_length = sizeof(double);
		return;

	case nod_negate:
		make_descriptor(node->nod_arg[0], desc);
		return;

	case nod_user_name:
		desc->dsc_dtype = dtype_varying;
		desc->dsc_scale = 0;
		desc->dsc_length = sizeof(USHORT) + 16;
		return;

	case nod_substr:
	default:
		BUGCHECK(362);			/* Msg362 make_descriptor: not yet implemented */
	}
}


static QLI_MSG make_message( QLI_REQ request)
{
/**************************************
 *
 *	m a k e _ m e s s a g e
 *
 **************************************
 *
 * Functional description
 *	Allocate a message block for a request.
 *
 **************************************/
	QLI_MSG message;

	message = (QLI_MSG) ALLOCDV(type_msg, 0);
	message->msg_request = request;
	message->msg_next = request->req_messages;
	request->req_messages = message;
	message->msg_number = request->req_msg_number++;

	return message;
}


static void make_missing_reference( PAR parameter)
{
/**************************************
 *
 *	m a k e _ m i s s i n g _ r e f e r e n c e
 *
 **************************************
 *
 * Functional description
 *	Make up a parameter to pass a missing value.
 *
 **************************************/
	PAR missing;

	if (parameter->par_missing)
		return;

	parameter->par_missing = missing = (PAR) ALLOCD(type_par);
	missing->par_message = parameter->par_message;
	missing->par_desc.dsc_dtype = dtype_short;
	missing->par_desc.dsc_length = sizeof(SSHORT);
}


static PAR make_parameter( QLI_MSG message, QLI_NOD node)
{
/**************************************
 *
 *	m a k e _ p a r a m e t e r
 *
 **************************************
 *
 * Functional description
 *	Make a parameter block and hang it off a message block.
 *	To make prompts come out in the right order, insert the
 *	new prompt at the end of the prompt list.  Sigh.
 *
 **************************************/
	PAR parm, *ptr;

	for (ptr = &message->msg_parameters; *ptr; ptr = &(*ptr)->par_next);

	*ptr = parm = (PAR) ALLOCD(type_par);
	parm->par_message = message;
	if (node && (node->nod_flags & NOD_parameter2))
		make_missing_reference(parm);

	return parm;
}


static QLI_NOD make_reference( QLI_NOD node, QLI_MSG message)
{
/**************************************
 *
 *	m a k e _ r e f e r e n c e
 *
 **************************************
 *
 * Functional description
 *	Make a reference to a value to be computed in the 
 *	database context.  Since a field can be referenced
 *	several times, construct reference blocks linking
 *	the single field to the single parameter.  (I think.)
 *	In any event, if a parameter for a field exists, 
 *	use it rather than generating an new one.   Make it
 *	parameter2 style if necessary.
 *
 **************************************/
	QLI_NOD reference;
	PAR parm;

	if (!message)
		BUGCHECK(363);			// Msg363 missing message 

// Look for an existing field reference 

	for (parm = message->msg_parameters; parm; parm = parm->par_next)
		if (CMP_node_match(parm->par_value, node))
			break;

/* Parameter doesn't exits -- make a new one. */

	if (!parm) {
		parm = make_parameter(message, node);
		parm->par_value = node;
		parm->par_desc = node->nod_desc;
	}

	reference = (QLI_NOD) ALLOCDV(type_nod, 1);
	reference->nod_type = nod_reference;
	reference->nod_arg[0] = node;
	reference->nod_desc = parm->par_desc;
	reference->nod_import = parm;

	return reference;
}


static QLI_REQ make_request( DBB dbb)
{
/**************************************
 *
 *	m a k e _ r e q u e s t
 *
 **************************************
 *
 * Functional description
 *	Make a request block for a database.
 *
 **************************************/
	QLI_REQ request;

	request = (QLI_REQ) ALLOCD(type_req);
	request->req_database = dbb;
	request->req_next = QLI_requests;
	QLI_requests = request;
	dbb->dbb_flags |= DBB_active;
	if (!(dbb->dbb_transaction))
		MET_transaction(nod_start_trans, dbb);

	return request;
}


static void release_message( QLI_MSG message)
{
/**************************************
 *
 *	r e l e a s e _ m e s s a g e
 *
 **************************************
 *
 * Functional description
 *	A message block is unneeded, so release it.
 *
 **************************************/
	QLI_MSG *ptr;
	QLI_REQ request;

	request = message->msg_request;

	for (ptr = &request->req_messages; *ptr; ptr = &(*ptr)->msg_next)
		if (*ptr == message)
			break;

	if (!*ptr)
		BUGCHECK(364);			// Msg 364 lost message 

	*ptr = message->msg_next;
	ALL_release((FRB) message);
}


static int string_length( DSC * desc)
{
/**************************************
 *
 *	s t r i n g _ l e n g t h
 *
 **************************************
 *
 * Functional description
 *	Estimate length of string based on descriptor.
 *
 **************************************/

	return DSC_string_length(desc);
}