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Conference azur::mcc

Title:	DECmcc user notes file. Does not replace IPMT.
Notice:	Use IPMT for problems. Newsletter location in note 6187
Moderator:	TAEC::BEROUD

Created:	Mon Aug 21 1989
Last Modified:	Wed Jun 04 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	6497
Total number of notes:	27359

759.0. "MSL question" by LEVERS::LEVENSON () Wed Feb 27 1991 16:44

Can I have a RECORD defined in MSL, with one of the fields being a
SEQUENCE OF or a SET OF?

E.g.,

TYPE
	XxxRec = 44 RECORD
		field1 = 1 : Unsigned8;
		field2 = 2 : SEQUENCE OF Unsigned8;
		    END

Also, are there any other known limitations on nesting of constructed types?

thanks,
Herman

T.R	Title	User	Personal Name	Date	Lines
759.1	That RECORD will work just fine....	BOEHM::CAREY		`Thu Feb 28 1991 10:45`	15
	Your RECORD looks just fine. The most complex record I've worked with is a RECORD which contains as one of its fields a Variant RECORD which contains as one of its fields a SET OF Unsigned8s. It is ugly, but it works fine. The ILV code limits construction nesting to 12 levels I think (it may be 10). If you think you have an attribute deeper than that in your management model, you would do well to re-evaluate it. We could extend our ILV capabilities, but it is VERY difficult to interpret attributes nested that deeply, so usability is almost certainly compromised. -Jim Carey
759.2	Oops...	BOEHM::CAREY		`Thu Feb 28 1991 10:46`	7
	Oops, I just re-read this. It as a RECORD containing a SET OF Variant RECORDS, each of which contains a SET OF Unsigned8s. Even uglier than I thought.
759.3	latest kit for most constructed of constructed	GOSTE::CALLANDER		`Fri Mar 01 1991 17:02`	14
	this probably will NOT work in the kit that you have unless you have the absolute latest and greatest, and even then it will only work if it is a record and NOT a variant records. Currently variant records are supported on output only, if you try to define this as an input arg you will fail. We have done a lot of work in the nested construted data type space hopefully we got them all, but I admit I am not ready to bet my job on it yet. If you do find out that it doesn't work, please contact me off-line and I will look into it (BTW: I am out of town for about a week). jill
759.4	ILV and ASN have their own limits	TOOK::KOHLS	Ruth Kohls	`Mon Mar 04 1991 10:40`	27
	ILV - ASN limitations: These limitations are ILV or ASN implementation limits, in addition to the limits that Jill Callander and others have mentioned (in various places) for Console handling of datatypes. Constructions may be nested 12 deep, including the Put_param_begin as the first level. This limit is a limit on nesting, not on the total number of constructions. A Put_cons_begin in List_value Mode opens 2 levels. The maximum buffer ILV-ASN will permit is 32500 bytes. It reserves 10 bytes at the end, so the minimum buffer it will accept is 10 bytes. An "empty" encoding will use 4 bytes (a begin-end construction pair with identifier). When planning the sizes of buffers for ILV encodings, you will need 2-4 bytes per value, and 4 bytes more per construction, for identifier and length encoding, etc. Why 12, 32500, 10? I don't know. Part of the answer is that ILV-ASN does not do dynamic memory or memory management of any type, and the context area you pass ILV or ASN is fixed size and structure. I would like to know if you all out there are cramped by these limits. Please let me know, either here in the MCC notes file, or by mail to TOOK::KOHLS. Ruth