Protocol-A.texi 266 KB
Newer Older
David Byers's avatar
David Byers committed
1
\input texinfo                         @c -*-texinfo-*-
David Byers's avatar
David Byers committed
2 3 4
@c
@c FIXME: Explain how the garb works with nice and keep-commented
@c
5
@c $Id: Protocol-A.texi,v 1.51 1999/01/15 11:16:04 byers Exp $
David Byers's avatar
David Byers committed
6 7 8 9 10 11 12
@c %**start of header
@setfilename protocol-a.info
@settitle LysKOM Protocol A
@setchapternewpage odd
@c %**end of header
@iftex
@parindent 0pt
13
@font@tensltt=cmsltt10
14 15 16 17 18
@begin tex
\global\def\rett#1{{\let\t\sltt\tt #1}}
\global\def\sltt#1{{\fam\ttfam\tensltt\let\t\rett #1}}
\global\let\t\sltt
@end tex
David Byers's avatar
David Byers committed
19 20 21
@end iftex

@ifinfo
22
This is the specification of LysKOM Protocol A v. 9.0
David Byers's avatar
David Byers committed
23

David Byers's avatar
David Byers committed
24
Copyright @copyright{} 1995-1999 Lysator ACS.
David Byers's avatar
David Byers committed
25 26 27 28 29 30

Permission is granted to make and distribute verbatim copies of this
specification provided the copyright notice and this permission notice
are preserved on all copies.
@end ifinfo

31 32 33 34 35
@dircategory LysKOM
@direntry
* Protocol A: (protocol-a).             The LysKOM Protocol A specification.
@end direntry

David Byers's avatar
David Byers committed
36 37 38 39
@titlepage
@sp 10
@title{LysKOM Protocol A}
@sp 2
40
@subtitle{Protocol version 10.0}
David Byers's avatar
David Byers committed
41 42 43 44 45
@sp 2
@author by the LysKOM Developers

@page
@vskip 0pt plus 1filll
David Byers's avatar
David Byers committed
46
Copyright @copyright{} 1995-1999 Lysator ACS
David Byers's avatar
David Byers committed
47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

Permission is granted to make and distribute verbatim copies of this document
provided the copyright notice and this permission notice are preserved on all
copies.

Modified versions of this document may be redistributed with the added
condition that all modifications not cleared with the LysKOM development group
are clearly marked and that the entire modified work be redistributed under the
same conditions as the original.

Permission is granted to copy and distribute translations of this manual into
another language under the same conditions as for modified versions.

@end titlepage

@ifinfo
@node Top, Overview, (dir), (dir)
@comment node-name, next, previous, up
Per Cederqvist's avatar
Per Cederqvist committed
65
This document specifies LysKOM Protocol A, version 9.0.
David Byers's avatar
David Byers committed
66

67 68 69 70
FIXME: This document is not yet published.  The document you are looking
at has the version numbers all wrong.  This will be fixed before
publication.

David Byers's avatar
David Byers committed
71 72 73 74 75 76
@menu
* Overview::
* Introduction::
* Data Types::
* Protocol Requests::
* Asynchronous Messages::
77 78 79 80
* Error Codes::
* LysKOM Content Types::
* The User Area::
* Writing Clients::
81
* Importing and Exporting E-Mail::
82 83
* Type Index::
* Request Index::
David Byers's avatar
David Byers committed
84 85 86
@end menu
@end ifinfo

87
@node Overview, Introduction, Top, Top
David Byers's avatar
David Byers committed
88 89 90
@chapter Overview

LysKOM is a conferencing system@footnote{Or in modern terms, enabling
91 92 93 94 95 96
technology for Computer-Supported Cooperative Work (CSCW).}. Similar
systems were QZ-KOM and PortaCOM@footnote{Also known as ``PottaKOM'' and
``BortaKOM.''}. The LysKOM system is copyrighted by Lysator Academic
Computing Society and distributed under conditions of the GNU Public
License. LysKOM and its documentation is provided ``as is'' without
warranty of any kind.
David Byers's avatar
David Byers committed
97

98 99 100
This document specifies version 10.0 of protocol A used between a LysKOM
client and a LysKOM server. Anything described here as ``unspecified''
is liable to change in future protocol versions.
David Byers's avatar
David Byers committed
101 102

This specification is the work of several people. The main contributors have
103 104 105
been
Per Cederqvist @code{<ceder@@lysator.liu.se>}, 
David Byers @code{<byers@@lysator.liu.se>},
David Byers's avatar
David Byers committed
106 107 108 109 110 111
@ifinfo
Pär
@end ifinfo
@iftex
P@"ar
@end iftex
112 113 114
Emanuelsson @code{<pell@@lysator.liu.se>},
Thomas Bellman @code{<bellman@@lysator.liu.se>}, 
Lars Aronsson @code{<aronsson@@lysator.liu.se>},
David Byers's avatar
David Byers committed
115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132
Linus Tolke @code{<linus@@lysator.liu.se>} and
@ifinfo
Kent Engström
@end ifinfo
@iftex
Kent Eng@-str@"om@penalty-10000
@end iftex
@code{<kent@@lysator.liu.se>}.

The LysKOM developers can be reached by email to @code{lyskom@@lysator.liu.se}.

@menu 
* Document Revision History::
* Protocol Revision History::
* Protocol Design Principles::
* Notation::
@end menu

133
@node Document Revision History, Protocol Revision History,, Overview
David Byers's avatar
David Byers committed
134 135 136
@section Document Revision History

@table @asis
137

138 139 140 141
@item 9.0: @i{In progress}
Protocol version 9 is begin developed and this document needs to be
updated.

David Byers's avatar
David Byers committed
142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
@item 8.0: 1995-11-10
Protocol version 8 is being documented. This specification was translated to
English and converted to Texinfo by David Byers.

@item 7.1: 1995-01-08.
Protocol and document revision history were added by Per Cederqvist. Outline
mode was used to make the document more manageable. This version was
distributed with lyskomd 1.7.1.

@item 7.0: 1994-12-31.
The first specification with a version number. All calls that had been added
since 1991-06-25 were documented. Pell and Per Cederqvist did the deed. This
version was distributed with lyskomd 1.7.0.

@item 1993-05-19.
Linus Tolke wrote comments for some calls that were without comments.

@item 1992-07-06.
Linus Tolke converted the document to ISO 8859-1.

@item 1991-08-12.
Per Cederqvist started using version control for documentation.

@item 1991-06-25.
Lars Aronsson documented the protocol that was in use at the time.
@end table

@node Protocol Revision History, Protocol Design Principles, Document Revision History, Overview
@section Protocol Revision History

172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188
@subsection Protocol version 10.0
@table @asis
@item New Server Calls
@itemize @bullet
@item 85=get-collate-table
@item 86=create-text
@item 87=create-anonymous-text
@item 88=create-conf
@item 89=create-person
@item 90=get-text-stat
@item 91=get-conf-stat
@item 92=modify-text-info
@item 93=modify-conf-info
@item 94=get-info
@item 95=modify-system-info
@item 96=query-predefined-aux-items
@item 97=set-expire
189 190 191 192
@item 98=query-read-texts
@item 99=get-membership
@item 100=add-member
@item 101=get-members
193 194
@item 102=local-to-global
@item 103=map-created-texts
David Byers's avatar
David Byers committed
195
@item 105=set-keep-commented
196 197 198 199 200
@end itemize

@item Removed Server Calls
@itemize @bullet
@item  5=create-person
201
@item  9=query-read-texts
202
@item 10=create-conf
203
@item 14=add-member
204 205 206
@item 26=get-text-stat
@item 28=create-text
@item 36=get-info-old
207 208
@item 46=get-membership-old
@item 48=get-members-old
209 210 211 212 213 214
@item 50=get-conf-stat
@item 59=create-anonymous-text
@end itemize

@item New and New Modified Structures
@itemize @bullet
215
@item Aux-Item
216
@item Aux-Item-Input
217 218
@item Conference
@item Info
219 220 221
@item Member
@item Membership
@item Membership-Type
222 223
@item Misc-Info
@item Text-Stat
224 225 226 227 228 229 230
@end itemize

@item New Asynchronous Messages
@itemize @bullet
@item async-deleted-text message
@item New async-new-text message
@end itemize
231 232 233 234 235 236 237 238 239 240 241 242 243

@item Notes
@itemize @bullet
@item Since protocol version 9 setting a priority of zero in a
conference was supposed to indicate passive membership in a conference. 
It was largely up to the client to implement this. True passive
memberships have been introduced in this protocol version through the
Membership-type extension to Membership type. In order to maintain
compatibility with clients that interpret priority 0 as passive
membership, the old calls @pxref{add-member-old} and
@pxref{get-membership-old} perform magic, translating between priorities 
and membership types. The magic is documented with each call.
@end itemize
244 245
@end table

246

247 248 249
@subsection Protocol version 9.0

@table @asis
Per Cederqvist's avatar
Per Cederqvist committed
250
@item Added Commands
251
@itemize @bullet
252 253 254 255 256 257
@item 79=set-info: Can change server information.
@item 80=accept-async: Can select asynchronous messages to receive.
@item 81=query-async: Can query which messages are being send.
@item 82=user-active
@item 83=who-is-on-dynamic
@item 84=get-static-session-info
258 259 260
@end itemize
@end table

David Byers's avatar
David Byers committed
261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304
@subsection Protocol version 8.0

@table @asis 
@item Added Functionality
@itemize @bullet
@item
30=add-recipient: Can change recpt to cc_recpt and vice versa.
@item
21=set-conf-type: Accepts Conf-Type and Extended-Conf-Type.
@item
10=create-conf: Accepts Conf-Type and Extended-Conf-Type.
@end itemize

@item New Commands
@itemize @bullet
@item
77=set-last-read
@item
78=get-uconf-stat
@end itemize
@end table

@subsection Protocol version 7 (first implemented in lyskomd 1.7.0)

@table @asis
@item Added Functionality
@itemize @bullet
@item
53=send-message: Recipient can be a conference or a person.
@end itemize

@item New Commands
@itemize @bullet
@item
74=re-z-lookup
@item
75=get_version_info
@item
76=lookup_z_name
@end itemize

@item Other
@itemize @bullet
@item
Per Cederqvist's avatar
Per Cederqvist committed
305
The asynchronous message 1=i-am-off has been removed
David Byers's avatar
David Byers committed
306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398
@end itemize
@end table

@subsection Protocol Version 6 (first implemented in lyskomd 1.4.0)

@table @asis
@item New Calls
@itemize @bullet
@item
67=lookup_person
@item
68=lookup_conf
@item
69=set_client_version
@item
70=get_client_name
@item
71=get_client_version
@item
72=mark_text
@item
73=unmark_text
@end itemize
@end table


@subsection Protocol Version 5 (first implemented in lyskomd 1.3.0)

@table @asis
@item New Calls
@itemize @bullet
@item
65=re_lookup_person
@item
66=re_lookup_conf
@end itemize
@end table

@subsection Protocol Version 4 (first implemented in lyskomd 1.1.1)

@table @asis
@item New Calls
@itemize @bullet
@item
62=login
@item
63=who_is_on_ident
@item
64=get_session_info_ident
@end itemize
@end table

@subsection Protocol Version 3 (first implemented in lyskomd 1.1.0)

@table @asis
@item New Calls
@itemize @bullet
@item
61=find_previous_text_no
@item
60=find_next_text_no
@item
59=create_anonymous_text
@item
58=get_last_text
@end itemize
@end table

@subsection Protocol Version 2 (first implemented in lyskomd 0.30.0)

@table @asis
@item New Calls
@itemize @bullet
@item
57=set_user_area
@end itemize
@end table

@subsection Protocol Version 1 (first implemented in lyskomd 0.29.2)

@table @asis
@item New Calls
All calls from 0--56.
@end table


@node Protocol Design Principles, Notation, Protocol Revision History, Overview
@section Transport Protocol Requirements

LysKOM protocol A can be run on top of any reliable, bidirectional,
8-bit data stream. All current implementations use TCP/IP. At Lysator
port 4894 is used on the host @code{kom.lysator.liu.se}.

399
Data in protocol A is ASCII clear text except within Hollerith strings,
400 401 402 403
where arbitrary eight-bit characters are allowed. Data arguments are
separated by whitespace. The reason for this unorthodox design is that
the protocol should be usable from a text-only terminal, something that
is very useful during server and early client development.
David Byers's avatar
David Byers committed
404 405 406 407 408


@node Notation, , Protocol Design Principles, Overview
@section Notation

409 410 411
This specification uses a BNF-like grammar to describe the protocol and
its data elements. It does not use ASN.1 because we don't know ASN.1 and
probably wouldn't like it very much even if we did.
David Byers's avatar
David Byers committed
412

413
Data fields have been given names that start with a lower-case letter.
414 415 416 417 418 419 420 421 422 423 424

Fundamental data types have names in all-caps (such as @code{INT32} and
@code{ARRAY}).

Derived data types have names that start with an upper-case letter. (If
the type contains more than one word, all words start with an upper-case
letter, like this: @code{Text-Stat}.)  The operator @code{::=} defines
the name to its left.

Comments start with @code{!} (exclamation mark) and alternatives are
separated by a @code{|} (vertical bar.) A @code{;} (semicolon)
425 426 427
terminates statements in the grammar. In some specifications there are
literal strings. There is to be no whitespace before or after literal
strings unless there is whitespace in the literal itself.
David Byers's avatar
David Byers committed
428 429


430
@node Introduction, Data Types, Overview, Top
David Byers's avatar
David Byers committed
431 432 433 434 435 436 437 438 439 440
@chapter Introduction

This chapter introduces the concepts used in LysKOM, such as articles,
conferences and sessions. 

@menu
* Articles ::
* Conferences ::
* Persons and Sessions ::
* The Misc-Info List ::
441
* The Aux-Item List ::
David Byers's avatar
David Byers committed
442 443 444 445 446 447 448 449 450 451 452
* Security ::
* Membership and Reading::
* Client-Server Dialog ::
@end menu


@node Articles, Conferences, , Introduction
@section Articles

An article is represented as a value of the type @code{Text-Stat} and a
string containing the article contents. An article will usually have one
453 454 455 456
or more recipients and may be a comment or footnote to other articles.
Each article is kept in the database until it is older than the
@code{nice} value of each of its recipients and it is not marked by any
user.
David Byers's avatar
David Byers committed
457

458 459 460 461 462
Currently there is a structure called a @code{Misc-Info-List} associated
with the @code{Text-Stat}. This list contains information about
recipients, senders, comments and footnotes. In the future the
information contained in the @code{Misc-Info-List} will be integrated
into the @code{Text-Stat}.
David Byers's avatar
David Byers committed
463 464 465

Every article has at least one number, the global article number. Global
numbers are assigned in ascending order to new articles, and are never
466
reused. If an article has recipients it will also have a local number
Per Cederqvist's avatar
Per Cederqvist committed
467
for each recipient. Local numbers are used in some data structures to
468
provide more compact storage and to provide an ordering of articles for
469 470 471
a particular recipient. Local numbers are assigned in ascending order
and are never reused for a particular recipient, though different
recipients will have articles with the same local numbers.
David Byers's avatar
David Byers committed
472

473
Occasionally it is necessary to map between local and global numbers.
474
The server call @code{local-to-global} does this.
David Byers's avatar
David Byers committed
475 476 477 478 479 480



@node Conferences, Persons and Sessions, Articles, Introduction
@section Conferences

481 482 483 484
Conferences hold articles. They are represented in the protocol as a
data type called @code{Conference}. Each conference has a
@emph{creator}, the person who created the conference, and a
@emph{supervisor}, a conference whose members can modify the conference.
David Byers's avatar
David Byers committed
485
If the supervisor is a person, the members of that person's mailbox
486 487 488 489 490
are supervisors, which in most cases is only that person. We have also
introduced a type called @code{UConference} (pronounced micro-conf-stat)
which holds a subset of the information contained in the full
@code{Conference} type. Use the @code{UConference} type whenever
possible since it places a much smaller load on the LysKOM server.
David Byers's avatar
David Byers committed
491 492

Each conference has a type, which is essentially a collection of boolean
Per Cederqvist's avatar
Per Cederqvist committed
493
flags. Currently the flags @code{rd-prot}, @code{letterbox},
494
@code{secret}, @code{original} and @code{allow-anonymous} are defined.
David Byers's avatar
David Byers committed
495 496 497 498 499 500 501

@table @code
@item rd-prot
The conference is protected from reading by non-members. Persons become
members by having one of the existing members or supervisors add him or
her to the conference. This restriction is enforced by the server.
@item original
502 503 504 505
Conferences of this type are intended for original articles only.
Comments are to be redirected to the super-conference instead. This
restriction is currently not enforced by the server; clients must
implement this functionality.
David Byers's avatar
David Byers committed
506
@item letterbox
507
Conferences of this type are connected to persons. Letters to a person
David Byers's avatar
David Byers committed
508
are sent to the mailbox and the name of the mailbox is synchronized
509 510
with the person name. It is currently not possible to explicitly set or
clear this flag on a conference.
David Byers's avatar
David Byers committed
511 512 513
@item secret
Conferences of this type are secret. The server will not divulge any
information of the existence of the conference to persons who are not
David Byers's avatar
David Byers committed
514
members or supervisors of the conference. If a mailbox is made secret,
David Byers's avatar
David Byers committed
515 516
that person cannot log in using the person name, but must specify a
person number instead.
517 518 519
@item allow-anonymous
Conferences of this type accept anonymous articles. Other conferences
will reject anonymous articles.
David Byers's avatar
David Byers committed
520 521 522
@item forbid-secret
Conferences of this type do not allow secret members. If a conference is 
changed to this type, preexisting secret members remain secret.
David Byers's avatar
David Byers committed
523 524 525 526 527 528 529 530
@end table



@node Persons and Sessions, The Misc-Info List, Conferences, Introduction
@subsection Persons and Sessions

Persons are represented in the protocol by values of the type
531 532 533 534
@code{Person}. Associated with persons are statistics, a set of personal
flags and a set of privileges (@pxref{Security}.) Persons are also
associated with a conference that has the same number as the person and
the @code{letterbox} bit set.
David Byers's avatar
David Byers committed
535 536

Connections to the server are represented as values of the type
537 538 539 540 541 542
@code{Static-Session-Info}, @code{Session-Info-Ident} or
@code{Session-Info}. Sessions have session number that are unique for
each session in the lifetime of the server execution. A single user can
have several sessions running at once. The session is not released until
the network connection is closed; a user can log in and out repeatedly
in a single session.
David Byers's avatar
David Byers committed
543 544


545
@node The Misc-Info List, The Aux-Item List, Persons and Sessions, Introduction
David Byers's avatar
David Byers committed
546 547
@section The Misc-Info List

548 549
The @code{Misc-Info} list contains tagged data. The fields are sent in
groups pertaining to a particular type of information: information about
550 551
recipient; carbon copy recipient; blank carbon copy recipient;
comment to; footnote to; comment in
552 553 554
and footnote in. The information groups may be sent in any order and
there may be any number of groups. Within each group the elements are
always sent in the order listed below.
David Byers's avatar
David Byers committed
555

556
@subsection Recipient
David Byers's avatar
David Byers committed
557 558 559

@table @code
@item recpt
560 561
Starts a recipient group. It contains the conference number of a
recipient of the article.
David Byers's avatar
David Byers committed
562
@item loc-no
563 564 565
Always present within a recipient group. It contains the local text
number of the article in the conference specified by the preceding
@code{recpt} field.
David Byers's avatar
David Byers committed
566
@item rec-time
567 568 569
If the recipient is a person, this element is added by the server when
the recipient marks the article as read. It contains the time when the
text was read.
David Byers's avatar
David Byers committed
570
@item sent-by
571 572 573
Present when the recipient was added by a person other than the author
(after the article was created.) It contains the person number of the
person who added the recipient.
David Byers's avatar
David Byers committed
574
@item sent-at
575 576
Present when the recipient was added after the article was created. It
contains the time when the recipient was added.
David Byers's avatar
David Byers committed
577 578 579
@end table


580
@subsection Carbon Copy (CC) Recipient
David Byers's avatar
David Byers committed
581

582 583 584 585
The carbon-copy recipient group is identical to the recipient group
above. The difference is how new comments to an article with a recipient
or carbon-copy recipient are treated. A comment to an article is sent to
all recipients, but not to carbon-copy recipients of the original
Per Cederqvist's avatar
Per Cederqvist committed
586
article. This difference is enforced by the clients.
David Byers's avatar
David Byers committed
587 588 589

@table @code
@item cc-recpt
590 591
Starts a carbon-copy recipient group. It contains the conference number
of a carbon-copy recipient of the article.
David Byers's avatar
David Byers committed
592
@item loc-no
593 594 595
Always present in a CC recipient group. It contains the local text
number of the article in the conference specified by the most recent
@code{cc-recpt} field.
David Byers's avatar
David Byers committed
596
@item rec-time
597
Present after the CC recipient has read the article. It contains the
598 599
time when the article was read. Since only persons can read articles
this will only be seen if the CC recipient is a person.
David Byers's avatar
David Byers committed
600 601 602
@item sent-by
Present when a CC recipient was added by a person other than the author
after the article had been created. It contains the person number of the
603
person who added the CC recipient.
David Byers's avatar
David Byers committed
604 605 606 607 608 609
@item sent-at
Present when a CC recipient was added after the article had been
created. It is the time when the CC recipient was added.
@end table


610 611 612 613 614 615 616 617 618 619 620 621 622 623
@subsection Blank Carbon Copy (BCC) Recipient

The blank carbon-copy recipient group is identical to the carbon-copy
recipient group above. The difference is the visibility of the
information. A carbon-copy recipient group is visible to anyone that is
allowed to fetch both the text status of the involed text and the
conference status of the involved conference.  (That is, as long as the
conference isn't secret everybody is allowed to se the carbon-copy
recipient group.)

A BCC recipient group is only visible to members and supervisors of the
recipient.  This is enforced by the server.

This type of group was introduced in protocol version 10.  When
624
old-style calls such as @xref{get-text-stat-old} are used this
625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649
will be converted to a CC recipient group by the server for the benefit
of clients that don't understand this group.

@table @code
@item bcc-recpt
Starts a blank carbon-copy recipient group. It contains the conference
number of a blank carbon-copy recipient of the article.
@item loc-no
Always present in a BCC recipient group. It contains the local text
number of the article in the conference specified by the most recent
@code{bcc-recpt} field.
@item rec-time
Present after the BCC recipient has read the article. It contains the
time when the article was read. Since only persons can read articles
this will only be seen if the BCC recipient is a person.
@item sent-by
Present when a BCC recipient was added by a person other than the author
after the article had been created. It contains the person number of the
person who added the BCC recipient.
@item sent-at
Present when a BCC recipient was added after the article had been
created. It is the time when the BCC recipient was added.
@end table


650
@subsection Comment To
David Byers's avatar
David Byers committed
651 652 653 654 655 656 657 658 659 660 661 662 663 664

@table @code
@item comm-to
Always present when the article is a comment to another article.
@item sent-by
Present when the article was added as a comment by a person other than
the author, after the article had been created. It contains the person
number of the person who added the article as a comment.
@item sent-at
Present when the article was added as a comment after the article had
been created. It contains the time when is was added as a comment.
@end table


665
@subsection Footnote To
David Byers's avatar
David Byers committed
666 667

@table @code
668
@item footn-to
David Byers's avatar
David Byers committed
669 670 671 672 673 674 675
Always present when the article is a footnote to another article.
@item sent-at
Present when the article was added as a footnote after the article had
been created. It contains the time when is was added as a footnote.
@end table


676
@subsection Comment in
David Byers's avatar
David Byers committed
677 678 679 680 681 682 683 684

@table @code
@item comm-in
Present when there are comments to this article. It contains the article
number which is a comment to this article.
@end table


685
@subsection Footnote in
David Byers's avatar
David Byers committed
686 687

@table @code
688
@item footn-in
David Byers's avatar
David Byers committed
689 690 691 692 693
Present when there are footnotes to this article. It contains the
article number which is a footnote to this article.
@end table


694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713
@node The Aux-Item List, Security, The Misc-Info List, Introduction
@subsection The Aux-Item List

The aux-item list is used as a generic extension mechanism in the LysKOM
server and in protocol A. 

@menu
* About Aux-Items ::
* Predefined Aux-Item Types ::
* Client-Specific Aux-Item Types ::
* Experimental Aux-Item Types ::
* Defining New Aux-Item Types ::
@end menu

@node About Aux-Items, Predefined Aux-Item Types, , The Aux-Item List
@subsubsection About Aux-Items

Aux-items were introduced in protocol version 10 as a mechanism for
extending the conference, text and server information structures without
changing the protocol. Persons were excluded since nobody could figure
David Byers's avatar
David Byers committed
714
out a case where setting an aux-item on the mailbox wasn't as good as
715 716 717 718 719 720 721 722 723
setting it on the person (another reason was that I was fed up writing
aux-item code by the time they were working on texts and conferences.)

The exact structure of an aux item is specified elsewhere (@pxref{LysKOM
Data Types}). The important fields here are the aux-no, tag and data
fields.

The aux-no field is used to identify an item. The aux-no together with a
text or conference number uniquely identifies a particular aux item.
724
Items are numbered from one and up within each item list. Once assigned,
725 726 727 728
the aux-no for an item is never changed. New items are guaranteed to
be assigned numbers that have never been used before within a particular
list.

729
The tag field identifies the type of aux item. It is used by the server
730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753
and by clients to figure out how to interpret the data field, and by the
server to decide if the item needs special treatment.

The data field is a simple string. The meaning of the string is
determined by the tag field, but since it is a string, clients that have
no understanding of the contents can successfully parse the item anyway
(in contrast to items in the misc-info list.)



@node Predefined Aux-Item Types, Client-Specific Aux-Item Types, About Aux-Items, The Aux-Item List
@subsubsection Predefined Aux-Item Types

Predefined Aux-Item types are part of Protocol A, and clients are
encouraged to support all of them. As with other parts of the protocol,
changes to these item types will probably always be
backwards-compatible.

Predefined types can case serious magic to be invoked in the server.
There is no limit to the strangeness that may be associated with this
type of item. The server may also place limits on who may create
predefined items, might verify the data field, and can force any field
in the item to a specific value, no matter what the client specified.

754
All items with tags in the range 1-9999 and 30000 and up are considered
755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774
predefined. If a client attempts to create an item with a tag in this
range, but the server has no idea what that tag means, the server will
return an error (KOM_ILL_AUX.)



@table @samp
@item content-type [1] (text)
Specifies the content type of a text. Data is a valid MIME type of one
of the special LysKOM types (@pxref{LysKOM Content Types}.)

This item may only be set by the author of a text. The inherit, secret
and hide-owner bits are cleared. Only one content-type item can be
created per creator.


@item fast-reply [2] (text)
Data is a string that constitutes a brief comment to the text. This
comment should be displayed immediately after the text body. 

David Byers's avatar
David Byers committed
775 776
An item of this type will never be inherited, can always be deleted, is
never anonymous and is never secret.
777 778 779


@item cross-reference [3] (text, conference)
David Byers's avatar
David Byers committed
780 781 782 783 784 785 786 787
Data is a cross-reference to something else. The contents consist of a
letter, a number, a space and a descriptive text. The letter must be one
of T, C or P. T specifies that the cross-reference points to a text; C
that it points to a conference; and P that it points to a person. The
number is the id of the target of the cross reference. The descriptive
text is simly that, a text that describes the cross-reference. For
example, "T15 Check this out!" is a cross reference to text 15 with a
description that reads "Check this out!".
788

David Byers's avatar
David Byers committed
789 790
The inherit bit is automatically cleared and the item can always be
deleted. 
791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823


@item no-comments [4] (text)
When this item is set, the author requests that nobody comments the
text. This is advisory only; it is still possible to write comments, but
clients should advise the user that this is contrary to the author's
wishes. Data should be empty.

This item may only be set by the author. The secret, hide-creator and
inherit bits are automatically cleared.


@item personal-comment [5] (text)
When this item is set, the author requests only personal comments. This
is advisory only; it is still possible to create regular comments, but
clients should advise the user that the author prefers a personal
comment. Data should be empty.

This item may only be set by the author. The secret, hide-creator and
inherit bits are automatically cleared.


@item request-confirmation [6] (text)
The author requests that everyone who reads the text confirms having
done so by creating read-confirmation items on the text. Clients should
ask users if they wish to confirm having read the text when it is
displayed. Data should be empty.

The hide-creator, secret and inherit bits are automatically cleared.


@item read-confirm [7] (text)
This item can be taken as confirmation that the item creator has read
824 825 826
the text to which the item is attached. Clients should never ever create
this item without an explicit confirmation from the user that the text
has indeed been read.
827 828

The hide-creator, secret and inherit bits are automatically cleared.
David Byers's avatar
David Byers committed
829
Once created an item of this type cannot be deleted.
830 831 832


@item redirect [8] (conference)
David Byers's avatar
David Byers committed
833

David Byers's avatar
David Byers committed
834 835 836 837 838 839 840 841 842 843 844
This item indicates that texts should not be sent to the conference,
but be directed to some other target instead. Clients should notify
users that attempt to send texts to the conference of the redirect and
offer to send the text to the target of the redirect instead. A typical
use of this item would be a user that does not read LysKOM very often
and would like to advise other users to send e-mail instead.

Data is PROTOCOL:ADDRESS where PROTOCOL is either "E-mail" or "LysKOM",
and ADDRESS is either an e-mail address or a LysKOM conference. 
Hopefully we'll be able to replace this with a forwarding mechanism
later.
845 846

This item can only be set by the conference supervisor or in the case of
David Byers's avatar
David Byers committed
847
a mailbox, the person attached to the mailbox. The hide-creator and
848 849 850
secret bits are cleared automatically. Only one redirect can be
specified.

David Byers's avatar
David Byers committed
851

852 853 854 855 856
@item x-face [9] (conference)

Data is the face of the person in compface format. Cool, innit?

This item can only be set by the conference supervisor or in the case of
David Byers's avatar
David Byers committed
857
a mailbox, the person attached to the mailbox. The hide-creator and
858 859 860
secret bits are cleared automatically. 


861
@item alternate-name [10] (text, conference)
862 863

Data is a string that the client may use as an alternate to the name of
David Byers's avatar
David Byers committed
864 865 866
a conference or the subject of a text. Note that the server does not
match against this name when performing name lookups. Clients should
only display alternate names created by the user currently logged on.
867 868 869 870 871 872 873

The inherit flag is automatically cleared.


@item pgp-signature [11] (text)

Data is a PGP signature of the text. The signature should be the
David Byers's avatar
David Byers committed
874
equivalent of what "pgp -sba" in PGP 2.6.2 generates.
875 876 877 878 879 880 881 882 883 884

The secret, hide-creator and inherit bits are automatically cleared.
Signatures cannot be deleted once they have been created.


@item pgp-public-key [12] (letterbox)

Data is the public key of the person. It is desirable that the public
key contains a userid of the format "LysKOM <p\([0-9]\)@@\(.*\)>+", where
\1 is the number of the person in the LysKOM server specified in \2.
David Byers's avatar
David Byers committed
885
This rule is currently not enforced.
886 887 888 889

This item can only be set by the person himself. The hide-creator,
secret and inherit bits are automatically cleared.

David Byers's avatar
David Byers committed
890

891 892
@item e-mail-address [13] (conference, letterbox, server)

David Byers's avatar
David Byers committed
893 894
Data is an RFC 822-style email address. When set on a mailbox, it
should be the email address of the person. If the person has multiple
895 896 897
email addresses he may set serveral e-mail-address aux-items.

The meaning of this aux-item when set on a conference that isn't a
David Byers's avatar
David Byers committed
898 899 900
mailbox is vague. For a conference that is used as to import a mailing
list this should be the email address of the list. For other conferences 
we haven't really defined a sensible use.
901 902 903 904

When this aux-item is set on the server it shold contain the email
address of the administrator (or administrators).

David Byers's avatar
David Byers committed
905 906 907
This aux-item can only be set by the supervisor of a conference or the
server administrator. The creator cannot be hidden.

908 909 910 911

@item faq-text [14] (conference, server)

Data is a decimal text number, which is a FAQ for the conference (or
David Byers's avatar
David Byers committed
912 913 914 915 916 917 918
server).  This aux-item can only be set by the administrator. Adding
this item to a conference or to the server automatically marks the text.
Deleting the item unmarks the text. 

This item can only be set by the supervisor or server administrator. The 
hide-creator, secret, and inherit bits are automatically cleared.

919 920 921 922 923 924 925 926 927 928 929 930

@item creating-software [15] (text)

Data is the name and version number of the client that created the
text.  This aux-item can only be set by the author of the text.  Once
set, it cannot be removed or changed.  A typical value would be
@samp{elisp-client 0.47.3}.  Setting the creating-software aux-item is
optional.

The data should be the client name, a space, and the client version used
in the @code{set-client-version} call.  The server may enforce this
restriction.
931

932
@item mx-author [16] (text)
933

934 935 936
Data is a string containing the name of the author of an imported
e-mail. Clients should display this instead of the actual author of the
text, which will be an importer ID.
937 938


939
@item mx-from [17] (text)
940

941 942 943
Data is the e-mail address extracted from the @code{From} header of an
imported e-mail. This field can be used by clients to construct an
address for personal (e-mail) replies to an imported message.
944 945


946
@item mx-reply-to [18] (text)
947

948 949 950
Data is the e-mail address extracted from the @code{Reply-To} header of
an imported e-mail. Clients should use this for constructing replies to
imported messages.
951 952


953
@item mx-to [19] (text)
954

955 956 957 958
Data is a single e-mail address, and must be valid as the contents of an
e-mail @code{To} header. Multiple @code{mx-o} items may be present. For
imported messages, these items contain the @code{To} header of the
messages.
959

960 961 962
On messages created by a LysKOM person, the @code{mx-to} items are used
by the exporter to determine that the message is to be exported and
where to send it.
963

964
@item mx-cc [20] (text)
965

966 967
Same as @code{mx-to}, but applies to the @code{CC} header rather than
the @code{To} header.
968

969

970
@item mx-date [21] (text)
971

972 973 974 975 976 977 978 979 980
Data is the send data of an imported e-mail. Its format is "YYYY-MM-DD
hh:mm:ss TZ". YYYY is the year the message was sent, MM is the month, DD 
is the day, hh is the hour, mm is the minute and ss is the second. This
date and time are given in the timezone where the message was sent. TZ
is the timezone the date is valid for. It must be of the form "+hhmm" or 
"-hhmm", where hh is the number of hours offset from UTC and mm is the
number of minutes offset. Symbolic timezones are not permitted. The
timezone specification is recommended but optional, since it is not
always available.
981

982 983
Clients should display this date as the date a text was written since
the imported text will have been created at a later date. 
984 985


986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007
@item mx-message-id [22] (text)

Data is the @code{Message-ID} header of an imported e-mail. This is used 
by e-mail importers. 


@item mx-in-reply-to [23] (text)

Data is a string containing one item from the @code{In-Reply-To} header
of an imported e-mail. If the @code{In-Reply-To} header contains several 
items, there will be several @code{mx-in-reply-to} items.


@item mx-misc [24] (text)

Data is a string that contains all of the headers, including
@code{Subject}, and including whose that are redundantly stored in other
aux-items. It is set by the importer. The fields are concatenated with
"\n". In other words, this item contains all headers of an imported
e-mail as they appear in the message.

@item mx-allow-filter [25] (conference)
1008 1009

Data is a regexp string which allows a sender (a field in the
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
email-header) to import the message. If none is present, the text is
imported. Several filters can exist, however, it is enough if one
positive filter matches (OR) and none negative dissallows (AND)
import. The order is of no importance. Can be set by an organizer of the
conference.

The regexp is case insensitive, and use a glob-pat style, it allows
[^]?*+(|) as constructs. Note that "." is literal. The importer is
required to check these when adding recipient of an imported text and
comply. Example of usage: (positive filter) "From:*.liu.se*",
"From:*jsk*". "From:*(jonas|jonka|jsk)*" Tests are not made on the
text-body.
1022 1023

However, if the string starts with a "!" the email will be rejected if
1024
the there is a match (negative filter), even if one of the filter allowed it.  Example:
1025 1026
"!From:*aol*", "!Subject:*money*". 

1027
@item mx-reject-forward [26] (conference)
1028

1029 1030
Data is a string with either an email name on the same format as
aux-info rediret [8]. The mail is forwarded to this address if it was
1031
rejected by "mx-import-filter".
1032

David Byers's avatar
David Byers committed
1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
@item notify-comments [27] (letterbox)

Data is a decimal text number that the user is interested in. Clients
should monitor this text for unread comments and present these to the
user in some convenient manner. This is typically used by users that
want to read comments to some text of theirs as soon as they arrive,
rather than in the normal reading order.

This item can only be set by the owner of the letterbox. No flags are
forced or cleared.
1043 1044


David Byers's avatar
David Byers committed
1045 1046
@end table

1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080

@node Client-Specific Aux-Item Types, Experimental Aux-Item Types, Predefined Aux-Item Types, The Aux-Item List
@subsubsection Client-Specific Aux-Item Types

Client-specific items do not cause the server to perform any magic. All
the flags (except the delete flag) are left untouched, the data is not
validated in any way, and anyone can create any item. If you need more
server support than this, your item should be on the predefined list.

All tags in the range 10000-19999 are reserved for clients. Blocks of
100 numbers at a time can be assigned to specific clients. A client
should never create items with tags in a range assigned to another
client or in an unassigned range. Assigned ranges will never change.

Currently, the following ranges are assigned to clients:
@itemize @bullet
@item 10000-10099: The Elisp Client
@end itemize

If you want a range of numbers, send e-mail to the LysKOM development
group.


@node Experimental Aux-Item Types, Defining New Aux-Item Types, Client-Specific Aux-Item Types, The Aux-Item List
@subsubsection Experimental Aux-Item Types

Experimental numbers are free for all. Use 'em any way you want. All
numbers in the range 20000-29999 are for experimental use. 



@node Defining New Aux-Item Types, , Experimental Aux-Item Types, The Aux-Item List
@subsubsection Defining New Aux-Item Types

1081
If you want a new predefined item type, just document what it does, what
1082 1083
the data format looks like and what the server is to do with the item
and send this to the LysKOM development group. We'll assign a number to
1084
your item and put the documentation in this document. 
1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104

If you're not sure what you want the data to look like yet, make a note
in your documentation that the data format might change. Once you have a
data format you're happy with, update the documentation so others may
use your item.

If you need serious magic in the server (more than can be specified with
the lyskomd configuration file), you'll probably have to write the code
yourself, or hope that the development group thinks your idea is so cool
we do the job for you.

The idea is not to reject any type of item, unless there's already an
item type that does the job just as well. Adding item types should be a
much less painful process than adding new calls.





@node Security, Membership and Reading, The Aux-Item List, Introduction
David Byers's avatar
David Byers committed
1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180
@subsection Security

Security in LysKOM is based on two components. Each person has a set of
privileges and each session has a security level. Rights in the system
require both the sufficient privileges and a sufficient security
level. The privileges currently available are wheel, admin, statistic,
create-conf, create-pers and change-name. Security levels range from 0
to 255.


@table @code
@item wheel
@emph{Normally not assigned}
@table @asis
@item Level 0
Person may always log in, even when LysKOM is crowded.
@item Level 6
Person may set Priv-Bits for all persons.
@item Level 7
Person may set password for all persons.
@item Level 8
Person acts as supervisor for everything.
@item Level 10
Person can read all articles.
@end table

@item admin
@emph{Normally not assigned}
@table @asis
@item Level 1
Shut down the server@*
Set motd_of_kom@*
Read last_login
@item Level 2
Read status of secret conferences and persons@*
Read the protected parts of person and conference statuses@*
Read the entire text status, even when there are secret recipients
@item Level 3
Change everybody's names
@item Level 4
Add/remove members@*
Add/remove recipients to articles
@item Level 5
Set super-conference@*
Remove articles
@item Level 6
Set administrator
@end table

@item statistic
@emph{Normally not assigned}
@table @asis
@item Level 2
Read the statistics portions of persons, even if protected
@end table

@item create_conf
@emph{Normally assigned}
@table @asis
@item Level 0
Create conferences
@end table

@item create_pers
@emph{Normally assigned}
@table @asis
@item Level 0
Create persons
@end table

@end table


@node Membership and Reading, Client-Server Dialog, Security, Introduction
@section Membership and Reading

1181
Persons' memberships in conferences are represented in the protocol as
1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204
arrays of @code{Membership}-typed values. This structure contains
information about how and when the membership was created and which
texts have been read in the conference.

There are two kinds of memberships. An active membership indicates that
the person is actively participating in the conference, wants to know if 
there are unread texts and wants to receive messages send to the
conference. A passive membership is similar to no membership at all. The 
person is still a member but will not receive messages sent to the
conference and will not be notified when there are new texts. From the
user's perspective, passive membership should be like no membership at
all, but the server still remembers what the user has read in the
conference while he or she was an active member. Since protocol version
10 a bit in the membership type field of the membership structure
indicates the type of membership. Previously the server did not support
passive memberships, but there was a convention that clients should
treat the priority level zero as a passive membership.

The membership record indicates which texts have been read through the
@code{last-text-read} and @code{read-texts} fields. All texts with local 
numbers up to @code{last-text-read} have been read. In addition, all
texts with local numbers contained in the @code{read-texts} array have
been read.
David Byers's avatar
David Byers committed
1205 1206

Finding out which articles a person has read in a particular conference
1207 1208
requires a few calls. Normally, a client will retrieve a batch of
perhaps 50 articles at a time. The outline of the process is as follows:
David Byers's avatar
David Byers committed
1209 1210 1211

@enumerate
@item Fetch the membership to get the @code{last-text-read}
1212 1213 1214 1215
@item Use @pxref{local-to-global} to translate a number of local numbers 
to global numbers. 
@item Remove the global numbers corresponding to local numbers contained 
in @code{read-texts} from the result
David Byers's avatar
David Byers committed
1216 1217 1218
@item Get and translate more texts as needed.
@end enumerate

1219
The process is complicated because of the translation between local and
1220
global text numbers. If the server does not implement the
1221 1222
@pxref{local-to-global} call, it is possible to use the less
efficient but perfectly serviceable @pxref{get-map} call instead.
David Byers's avatar
David Byers committed
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233


@node Client-Server Dialog, ,Membership and Reading , Introduction
@section Client-Server Dialog

The client-server dialog consists of two phases, establishing the connection
and the LysKOM session itself.

@subsection Connecting to the Server

A connection to the server is initiated by connecting to the appropriate
1234 1235 1236 1237
network port@footnote{The default port for a LysKOM server is 4894} and
sending a single letter which is used to select a protocol version
followed by connection information required by that protocol. In
protocol A the connection information is a Hollerith string saying who
1238
the user connecting is followed by a newline character.
David Byers's avatar
David Byers committed
1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252

When the server has accepted the connection its reply is
protocol-dependent. Protocol A servers will reply with the string
@code{LysKOM} on a single line.

@example
        % telnet kom.lysator.liu.se
        Trying 130.236.254.151 ...
        Connected to varg.lysator.liu.se.
        Escape character is '^]'.
        A5Hbyers
        LysKOM
@end example

1253 1254 1255
After connecting, calls to the server can be made. Most calls require
the user to log in, but some calls can be made without a log-in. Calls
to the server are made by sending a reference number followed by the
1256 1257
call as specified. The call @i{must} be terminated with a newline
character, but extra newlines @i{within} the call are permitted.
David Byers's avatar
David Byers committed
1258 1259 1260 1261 1262 1263 1264 1265

@example
        server-call ::=
                ( ref-no        :       INT32;
                  request       :       Protocol-Request;
                )
@end example

1266 1267 1268
At some future point the server will reply with the result of the
request or an error code preceded by an indicator and the reference
number.
David Byers's avatar
David Byers committed
1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282

@example
        server-reply ::= ok-reply | error-reply;

        ok-reply ::=
                ( "="
                  ref-no        :       INT32;
                  reply-data;
                )

        error-reply ::=
                ( "%"
                  ref-no        :       INT32;
                  error-no      :       Error-No;
1283
                  error-status  :       INT32;
David Byers's avatar
David Byers committed
1284 1285 1286 1287 1288 1289
                )

        error-no ::= INT32;
@end example

Our notation is not flexible enough to specify the two-way nature of the
1290 1291 1292 1293 1294 1295
communication. @code{ref-no} in the reply is always the same as
@code{ref-no} in the corresponding request. @code{reply-data} depends on
which request was made and is specified together with each request.

Please note that there is no whitespace after the initial indicator in
the reply.
David Byers's avatar
David Byers committed
1296

1297
Error reporting is covered in more detail in chapter @ref{Error Codes}.
David Byers's avatar
David Byers committed
1298 1299


1300
@node Data Types, Protocol Requests, Introduction, Top
David Byers's avatar
David Byers committed
1301 1302
@chapter Data Types

1303 1304 1305 1306
The data types in protocol A come in two flavors. The first (vanilla)
are the simple data types from which the LysKOM (chocolate) data types
are built. Simple data types include things like integers and strings
while complex data types include things such as conferences and people.
David Byers's avatar
David Byers committed
1307 1308 1309 1310

@menu
* Simple Data Types::
* LysKOM Data Types::
1311
* Name Expansion::
David Byers's avatar
David Byers committed
1312 1313 1314 1315 1316
@end menu

@node Simple Data Types, LysKOM Data Types, Data Types, Data Types
@section Simple Data Types

1317 1318 1319 1320 1321
Data elements are sent from client to server separated by one or more
ASCII spaces (0x20), tab characters (0x09), line feeds (0x0A) or
carriage returns (0x0D.) In messages from server to client the data
elements are separated by exactly one space character and the entire
message terminated with a line feed.
David Byers's avatar
David Byers committed
1322 1323 1324 1325


@subsection Integers

1326 1327 1328 1329
@tindex INT32
@tindex INT16
@tindex INT8
@tindex BOOL
1330 1331 1332
@dfn{INT32}, @dfn{INT16}, @dfn{INT8} and @dfn{BOOL} are non-negative
integers which must fit in 32, 16, 8 and 1 bits, respectively. They are
transmitted to the server in ASCII-encoded decimal notation.
David Byers's avatar
David Byers committed
1333 1334 1335 1336


@subsection Strings

1337
@tindex HOLLERITH
David Byers's avatar
David Byers committed
1338 1339 1340
@dfn{HOLLERITH} denotes character strings of arbitrary length. They are
transmitted as @code{<n>H<text>} where @code{<text>} is the string and
@code{<n>} is the number of characters in @code{<text>} in decimal
1341 1342 1343 1344
notation. All byte values are allowed in the string itself, including
nulls.

Long live FORTRAN!
David Byers's avatar
David Byers committed
1345 1346 1347 1348 1349



@subsection Bit Strings

1350
@tindex BITSTRING
1351 1352
@dfn{BITSTRING} is a string of bits, commonly used for a set of
boolean-valued flags. Bit strings are denoted as
David Byers's avatar
David Byers committed
1353 1354 1355 1356 1357

@example
        BITSTRING ( name-1; name-2; name-3; ... )
@end example