1 <!doctype linuxdoc system>
4 $Id: ir-tcl.sgml,v 1.6 1995-06-01 16:36:56 adam Exp $
8 <title>IrTcl User's Guide and Reference
9 <author>Index Data, <tt/info@index.ping.dk/
10 <date>$Revision: 1.6 $
12 This document describes IrTcl &mdash an information retrieval toolkit for
13 Tcl and Tk that provides access to the Z39.50/SR protocol.
21 This document describes the <sf/IrTcl/ information retrieval toolkit,
22 which offers a high-level, client interface to the Z39.50 and SR protocols.
23 The toolkit is based on the Tcl/Tk toolkit developed by Prof. John
24 K. Ousterhout at the University of California [ref 1].
25 Tcl is a simple, somewhat shell-like, interpreted language. What
26 makes Tcl attractive is that it also offers a C API, which makes
27 extensions to the language possible. The most important Tcl extension is
28 probably Tk &mdash A Motif look-and-feel interface to the X window
31 To interface the Z39.50/SR protocol <sf/IrTcl/ uses <bf/YAZ/.
32 <bf/YAZ/ offers two transport types: RFC1729/BER on TCP/IP and the mOSI
34 However, the mOSI transport is only an option, and hence it is not
35 needed unless you wish to communicate within an OSI environment.
36 See [ref 2] for more information about the XTI/mOSI implementation.
38 <sf/IrTcl/ provides two system environments:
41 <item> A simple command line shell &mdash useful for
43 <item> A system which operates within the Tk environment which
44 makes it very easy to implement GUI clients.
50 Basically, <sf/IrTcl/ is a set of commands introduced to Tcl.
51 When extending Tcl there are two approaches: action-oriented commands
52 and object-oriented commands.
54 Action-oriented commands manipulate
55 Tcl variables and each command introduces only one action.
56 The string manipulation commands in Tcl are action oriented.
58 Object-oriented commands are added for every declared
59 variable (object). Object-oriented commands usually provide a set of
60 actions (methods) to manipulate the object.
61 The widgets in Tk (X objects) are examples of the object-oriented style.
63 <sf/IrTcl/ commands are object-oriented. The main reason
64 for this is that the data structures involved in the IR protocol
65 are not easily represented by Tcl data structures.
66 Also, the <sf/IrTcl/ objects tend to exist for a relativly long time.
67 Note that although we use the term object-oriented commands, this
68 does not mean that the programming style is strictly object-oriented. For
69 example, there is such no such thing as inheritance.
71 We are now ready to present the three commands introduced to Tcl by
75 <tag/ir/ The ir object represents a connection to a target. More
76 precisely it describes a Z-association.
77 <tag/ir-set/ The ir-set describes a result set, which is
78 conceptually a collection of records returned by the target.
79 The ir-set object may retrieve records from a target by means of
80 the ir object; it may read/write records from/to a local file or it may be
81 updated with a user-edited record.
82 <tag/ir-scan/ The scan object represents a list of scan lines
83 retrieved from a target.
88 To create a new IR object called <tt/z-assoc/ write:
95 Each object provides a set of <em/settings/ which may either be
96 readable, writeable of both. All settings immediately follow
97 the name of the object. If a value is present the setting
102 We wish to set the preferred-message-size to 18000 on the
106 z-assoc preferredMessageSize 18000
109 To read the current value of preferred-message-size use:
112 z-assoc preferredMessageSize
116 One important category consists of settings is those that relate to the
117 event-driven model. When <sf/IrTcl/ receives responses from the target, i.e.
118 init responses, search responses, etc., a <em/callback/ routine
119 is called. Callback routines are represented in Tcl as
120 a list, which is re-interpreted prior to invocation.
121 The method is similar to the one used in Tk to capture X events.
123 For each SR/Z39.50 request there is a corresponding object action. The most
124 important actions are:
126 <tag/connect/ Establishes connection with a target
127 <tag/init/ Sends an initialize request.
128 <tag/search/ Sends a search request.
129 <tag/present/ Sends a present request.
130 <tag/scan/ Sends a scan request.
135 This example shows a complete connect - init - search - present scenario.
137 First an IR object, called <tt/z/, is created.
138 Also a result set <tt/z.1/ is introduced by the <tt/ir-set/
139 and it is specified that the result set uses <tt/z/ as its association.
141 The setting <tt/databaseNames/ is set to the
142 database <tt/books/ to which the following searches are directed.
143 A callback is then defined and a connection is established to
144 <tt/fake.com/ by the <tt/connect/ action.
145 If the connect succeeds the <tt/connect-response/ is called.
147 In the Tcl procedure, <tt/connect-response/, a callback is defined
148 <em/before/ the init request is executed.
149 The Tcl procedure <tt/init-response/ is called when a
150 init response is returned from the target.
152 The <tt/init-response/ procedure sets up a <tt/search-response/
153 callback handler and sends a search-request by using a query which
154 consists of a single word <tt/science/.
156 When the <tt/search-response/ procedure is called it defines
157 a variable <tt/hits/ and sets it to the value of the setting
158 <tt/resultCount/. If <tt/hits/ is positive a present-request is
159 sent &mdash asking for 5 records from position 1.
161 Finally, a present response is received and the number of records
162 returned is stored in the variable <tt/ret/.
167 z databaseNames books
168 z callback {connect-response}
171 proc connect-response {} {
172 z callback {init-response}
176 proc init-response {} {
177 z.1 callback {search-response}
181 proc search-response {} {
182 set hits [z.1 resultCount]
185 z.1 callback {present-response}
190 proc present-response {} {
191 set ret [z.1 numberOfRecordsReturned]
192 puts "$ret records returned"
197 The previous example program doesn't care about error conditions.
198 If errors occur in the program they will be trapped by the Tcl error
199 handler. This is not always appropriate. However, Tcl offers a
200 <tt/catch/ command to support error handling by the program itself.
205 The ir object describes an association with a target.
206 This section covers the connect-init-disconnect actions provided
208 An ir object is created by the <tt/ir/ command and the
209 created object enters a 'not connected' state, because it isn't
210 connected to a target yet.
215 A connection is established by the <tt/connect/ action which is
216 immediately followed by a hostname. Obviously, these settings should
217 be set <bf/before/ connecting.
218 The settings that affect the <tt/connect/ action are:
221 <tag><tt>comstack </tt><tt>mosi|tcpip</tt></tag>
223 <tag><tt>protocol </tt><tt>Z3950|SR</tt></tag>
224 ANSI/NISO Z39.50 or ISO SR
225 <tag><tt>callback </tt><em>list</em></tag>
226 Tcl script called when the connection is established
227 <tag><tt>failback </tt><em>list</em></tag>
228 Fatal error Tcl script. Called on protocol errors or if target
232 If the connect is unsuccessful either the connect action itself
233 will return an error code or the failback handler is invoked.
238 If the connect operation succeeds the <tt/init/ action should be used.
239 The init related settings are:
242 <tag><tt>preferredMessageSize </tt><em>integer</em></tag>
243 Preferred-message-size
244 <tag><tt>maximumRecordSize </tt><em>integer</em></tag>
246 <tag><tt>idAuthentication </tt><em>string</em></tag>
248 <tag><tt>implementationName </tt><em>string</em></tag>
249 Implementation-name of origin system
250 <tag><tt>implementationId </tt><em>string</em></tag>
251 Implementation-id of origin system
252 <tag><tt>options </tt><em>list</em></tag>
253 Options to be negotiated in init. The list contains the options that
255 <tag><tt>protocolVersion </tt><em>integer</em></tag>
256 Protocol version: 2, 3, etc.
257 <tag><tt>initResponse </tt><em>list</em></tag>
258 Init-response Tcl script
259 <tag><tt>callback </tt><em>list</em></tag>
260 General response Tcl script. Only used if initResponse is not specified
263 The init-response handler should inspect some of the settings shown
267 <tag><tt>initResult </tt><em>boolean</em></tag>
269 <tag><tt>preferredMessageSize </tt><em>integer</em></tag>
270 Preferred-message-size
271 <tag><tt>maximumRecordSize </tt><em>integer</em></tag>
273 <tag><tt>targetImplementationName </tt><em>string</em></tag>
274 Implementation-name of target system
275 <tag><tt>targetImplementationId </tt><em>string</em></tag>
276 Implementation-id of target system
277 <tag><tt>targetImplementationVersion </tt><em>string</em></tag>
278 Implementation-version of target system
279 <tag><tt>options </tt><em>list</em></tag>
280 Options negotiated after init. The list contains the options that are set.
281 <tag><tt>protocolVersion </tt><em>integer</em></tag>
282 Protocol version: 2, 3, etc.
283 <tag><tt>userInformationField </tt><em>string</em></tag>
284 User information field
289 Consider a client with the ability to access multiple targets.
291 We define a list of targets that we wish to connect to.
292 Each item in the list describes the target parameters with
293 the following four components: association-name, comstack-type,
294 protocol-type and a hostname.
296 The list for the two targets: ISO/SR target DANBIB and TCP/Z39.50
297 target Data Research, will be defined as:
299 set targetList { {danbib mosi sr 0103/find2.denet.dk:4500}
300 {drs tcpip z39 dranet.dra.com} }
303 The Tcl code below defines, connect and initialize the
304 targets in <tt/targetList/:
307 \foreach target $targetList {
308 set assoc [lindex $target 0]
310 $assoc comstack [lindex $target 1]
311 $assoc protocol [lindex $target 2]
312 $assoc failback [list fail-response $assoc]
313 $assoc callback [list connect-response $assoc]
314 $assoc connect [lindex $target 3]
317 proc connect-response {assoc} {
318 $assoc initResponse [list init-response $assoc]
322 proc fail-response {assoc} {
323 puts "$assoc closed connection or protocol error"
326 proc init-response {assoc} {
327 if {[$assoc initResult]} {
328 puts "$assoc initialized ok"
330 puts "$assoc didn't initialize"
335 <tt/target/ is bound to each item in the list of targets.
336 The <tt/assoc/ is set to the ir object name.
337 Then, the comstack, protocol and failback are set for the <tt/assoc/ object.
338 The ir object name is argument to the <tt/fail-response/ and
339 <tt/connect-response/ routines.
340 Note the use of the Tcl <tt/list/ command which
341 is necessary here because the argument contains variables
342 (<tt/assoc/) that should be substituted before the handler is defined.
343 After the connect operation, the <tt/init-response/ handler
344 is defined in much the same way as the failback handler.
345 And, finally, an init request is executed.
351 To terminate the connection the <tt/disconnect/ action should be used.
352 This action has no parameters.
353 Another connection may be established by a new <tt/connect/ action on
359 This section covers the queries used by <sf/IrTcl/, and how searches and
360 presents are handled.
362 A search operation and a result set is described by the ir set object.
363 The ir set object is defined by the <tt/ir-set/ command which
364 has two parameters. The first is the name of the new ir set object, and
365 the second, which is optional, is the name of an assocation &mdash an ir
366 object. The second argument is required if the ir set object should be able
367 to perform searches and presents. However, it is not required if
368 only ``local'' operations is done with the ir set object.
370 When the ir set object is created a number of settings are inherited
371 from the ir object, such as the selected databass, query type,
372 etc. Thus, the ir object contains what we could call default
378 Search requests are sent by the <tt/search/ action which
379 takes a query as parameter. There are two types of queries,
380 RPN and CCL, controlled by the setting <tt/queryType/.
381 A string representation for the query is used in <sf/IrTcl/ since
382 Tcl has reasonably powerful string manipulaton capabilities.
383 The RPN query used in <sf/IrTcl/ is the prefix query notation also used in
384 the <bf/YAZ/ test client.
386 The CCL query is an uninterpreted octet-string which is parsed by the target.
387 We refer to the standard: ISO 8777. Note that only a few targets
388 actually support the CCL query and the interpretation of
389 the standard may vary.
391 The prefix query notation (which is converted to RPN) offer a few
395 <tag><tt>@attr </tt><em>list op</em></tag>
396 The attributes in list are applied to op
397 <tag><tt>@and </tt><em>op1 op2</em></tag>
398 Boolean <em/and/ on op1 and op2
399 <tag><tt>@or </tt><em>op1 op2</em></tag>
400 Boolean <em/or/ on op1 and op2
401 <tag><tt>@not </tt><em>op1 op2</em></tag>
402 Boolean <em/not/ on op1 and op2
403 <tag><tt>@prox </tt><em>list op1 op2</em></tag>
404 Proximity operation on op1 and op2. Not implemented yet.
405 <tag><tt>@set </tt><em>name</em></tag>
409 It is simple to build RPN queries in <sf/IrTcl/. Search terms
410 are sequences of characters, as in:
415 Boolean operators use the prefix notation (instead of the suffix/RPN),
418 @and science technology
421 Search terms may be associated with attributes. These
422 attributes are indicated by the <tt/@attr/ operator.
423 Assuming the bib-1 attribute set, we can set the use-attribute
424 (type is 1) to title (value is 4):
430 Also, it is possible to apply attributes to a range of search terms.
431 In the query below, both search terms have use=title but the <tt/tech/
432 term is right truncated:
435 @attr 1=4 @and @attr 5=1 tech beta
441 The settings that affect the search are listed below:
444 <tag><tt>databaseNames </tt><em>list</em></tag>
446 <tag><tt>smallSetUpperBound </tt><em>integer</em></tag>
447 small set upper bound
448 <tag><tt>largeSetLowerBound </tt><em>integer</em></tag>
449 large set lower bound
450 <tag><tt>mediumSetPresentNumber </tt><em>integer</em></tag>
451 medium set present number
452 <tag><tt>replaceIndicator </tt><em>boolean</em></tag>
454 <tag><tt>setName </tt><em>string</em></tag>
456 <tag><tt>queryType rpn|ccl</tt></tag>
457 query type-1 or query type-2
458 <tag><tt>preferredRecordSyntax </tt><em>string</em></tag>
459 preferred record syntax &mdash UNIMARC, USMARC, etc.
460 <tag><tt>smallSetElementSetNames </tt><em>string</em></tag>
461 small-set-element-set names
462 <tag><tt>mediumSetElementSetNames </tt><em>string</em></tag>
463 medium-set-element-set names
464 <tag><tt>searchResponse </tt><em>list</em></tag>
465 Search-response Tcl script
466 <tag><tt>callback </tt><em>list</em></tag>
467 General response Tcl script. Only used if searchResponse is not specified
470 Setting the <tt/databaseNames/ is mandatory. All other settings
471 have reasonable defaults.
472 The search-response handler, specified by the <tt/callback/ - or
473 the <tt/searchResponse/ setting,
474 should read some of the settings shown below:
477 <tag><tt>searchStatus </tt><em>boolean</em></tag>
479 <tag><tt>responseStatus </tt><em>list</em></tag>
480 response status information
481 <tag><tt>resultCount </tt><em>integer</em></tag>
483 <tag><tt>numberOfRecordsReturned </tt><em>integer</em></tag>
484 number of records retrieved
487 The <tt/responseStatus/ signals one of three conditions which
488 is indicated by the value of the first item in the list:
491 <tag><tt>NSD</tt></tag> indicates that the target has returned one or
492 more non-surrogate diagnostic messages. The <tt/NSD/ item is followed by
493 a list with all non-surrogate messages. Each non-surrogate message consists
494 of three items. The first item of the three items is the error
495 code (integer); the next item is a textual representation of the error
496 code in plain english; the third item is additional information, possibly
497 empty if no additional information was returned by the target.
499 <tag><tt>DBOSD</tt></tag> indicates a successful operation where the
500 target has returned one or more records. Each record may be
501 either a database record or a surrogate diagnostic.
503 <tag><tt>OK</tt></tag> indicates a successful operation &mdash no records are
504 returned from the target.
509 We continue with the multiple-targets example.
510 The <tt/init-response/ procedure will attempt to make searches:
513 proc init-response {assoc} {
514 puts "$assoc connected"
515 ir-set ${assoc}.1 $assoc
516 $assoc.1 queryType rpn
517 $assoc.1 databaseNames base-a base-b
518 $assoc.1 searchResponse [list search-response $assoc ${assoc}.1]
519 $assoc.1 search "@attr 1=4 @and @attr 5=1 tech beta"
523 An ir set object is defined and the
524 ir object is told about the name of ir object.
525 The ir set object use the name of the ir object as prefix.
527 Then, the query-type is defined to be RPN, i.e. we will
528 use the prefix query notation later on.
530 Two databases, <tt/base-a/ and <tt/base-b/, are selected.
532 A <tt/search-response/ handler is defined with the
533 ir object and the ir-set object as parameters and
534 the search is executed.
536 The first part of the <tt/search-response/ looks like:
538 proc search-response {assoc rset} {
539 set status [$rset responseStatus]
540 set type [lindex $status 0]
541 if {$type == "NSD"} {
542 set code [lindex $status 1]
543 set msg [lindex $status 2]
544 set addinfo [lindex $status 3]
545 puts "NSD $code: $msg: $addinfo"
548 set hits [$rset resultCount]
549 if {$type == "DBOSD"} {
550 set ret [$rset numberOfRecordsReturned]
555 The response status is stored in variable <tt/status/ and
556 the first element indicates the condition.
557 If non-surrogate diagnostics are returned they are displayed.
558 Otherwise, the search was a success and the number of hits
559 is read. Finally, it is tested whether the search response
560 returned records (database or diagnostic).
562 Note that we actually didn't inspect the search status (setting
563 <tt/searchStatus/) to determine whether the search was successful or not,
564 because the standard specifies that one or more non-surrogate
565 diagnostics should be returned by the target in case of errors.
568 If one or more records are returned from the target they
569 will be stored in the result set object.
570 In the case in which the search response contains records, it is
571 very similar to the present response case. Therefore, some settings
572 are common to both situations.
577 The <tt/present/ action sends a present request. The <tt/present/ is
578 followed by two optional integers. The first integer is the
579 result-set starting position &mdash defaults to 1. The second integer
580 is the number of records requested &mdash defaults to 10.
581 The settings which could be modified before a <tt/present/
585 <tag><tt>preferredRecordSyntax </tt><em>string</em></tag>
586 preferred record syntax &mdash UNIMARC, USMARC, etc.
587 <tag><tt>elementSetElementSetNames </tt><em>string</em></tag>
589 <tag><tt>presentResponse </tt><em>list</em></tag>
590 Present-response Tcl script
591 <tag><tt>callback </tt><em>list</em></tag>
592 General response Tcl script. Only used if presentResponse is not specified
595 The present-response handler should inspect the settings
596 shown in table ref{tab:irpresentresponse}.
597 Note that <tt/responseStatus/ and <tt/numberOfRecordsReturned/
598 settings were also used in the search-response case.
600 As in the search-response case, records returned from the
601 target are stored in the result set object.
604 <tag><tt>presentStatus </tt><em>boolean</em></tag>
606 <tag><tt>responseStatus </tt><em>list</em></tag>
607 Response status information
608 <tag><tt>numberOfRecordsReturned </tt><em>integer</em></tag>
609 number of records returned
610 <tag><tt>nextResultSetPosition </tt><em>integer</em></tag>
611 next result set position
617 Search responses and present responses may result in
618 one or more records stored in the ir set object if
619 the <tt/responseStatus/ setting indicates database or
620 surrogate diagnostics (<tt/DBOSD/). The individual
621 records, indexed by an integer position, should be
624 The action <tt/type/ followed by an integer returns information
625 about a given position in an ir set. There are three possiblities:
628 <tag><tt/SD/</tag> The item is a surrogate diagnostic record.
629 <tag><tt/DB/</tag> The item is a database record.
630 <tag><em/empty/</tag> There is no record at the specified position.
633 To handle the first case, surrogate diagnostic record, the
634 <tt/Diag/ action should be used. It returns three
635 items: error code (integer), text representation in plain english
636 (string), and additional information (string, possibly empty).
638 In the second case, database record, the <tt/recordType/ action should
639 be used. It returns the record type at the given position.
640 Some record types are:
657 We continue our search-response example. In the case,
658 <tt/DBOSD/, we should inspect the result set items.
659 Recall that the ir set name was passed to the
660 search-response handler as argument <tt/rset/.
663 if {$type == "DBOSD"} {
664 set ret [$rset numberOfRecordsReturned]
665 for {set i 1} {$i<=$ret} {incr i} {
666 set itype [$rset type $i]
667 if {$itype == "SD"} {
668 set diag [$rset Diag $i]
669 set code [lindex $diag 0]
670 set msg [lindex $diag 1]
671 set addinfo [lindex $diag 2]
672 puts "$i: NSD $code: $msg: $addinfo"
673 } else if {$itype == "DB"} {
674 set rtype [$rset recordType $i]
675 puts "$i: type is $rtype"
680 Each item in the result set is examined.
681 If an item is a diagnostic message it is displayed; otherwise
682 if it's a database record its type is displayed.
688 In the case, where there is a MARC record at a given position we
689 want to display it somehow. The action <tt/getMarc/ is what we need.
690 The <tt/getMarc/ is followed by a position integer and the type of
691 extraction we want to make: <tt/field/ or <tt/line/.
693 The <tt/field/ and <tt/line/ type are followed by three
694 parameters that serve as extraction masks.
695 They are called tag, indicator and field.
696 If the mask matches a tag/indicator/field of a record the information
697 is extracted. Two characters have special meaning in masks: the
698 dot (any character) and star (any number of any character).
700 The <tt/field/ type returns one or more lists of field information
701 that matches the mask specification. Only the content of fields
704 The <tt/line/ type, on the other hand, returns a Tcl list that
705 completely describe the layout of the MARC record &mdash including
708 The <tt/field/ type is sufficient and efficient in the case, where only a
709 small number of fields are extracted, and in the case where no
710 further processing (in Tcl) is necessary.
712 However, if the MARC record is to be edited or altered in any way, the
713 <tt/line/ extraction is more powerful &mdash only limited by the Tcl
718 Consider the record below:
723 008 910710c19910701nju 00010 eng
727 100 10 $a Jack Collins
728 245 10 $a How to program a computer
734 Assuming this record is at position 1 in ir-set <tt/z.1/, we
735 might extract the title-field (245 * a), with the following command:
737 z.1 getMarc 1 field 245 * a
742 {How to program a computer}
745 Using the <tt/line/ instead of <tt/field/ gives:
747 {245 {10} {{a {How to program a computer}} }}
750 If we wish to extract the whole record as a list, we use:
752 z.1 getMarc 1 line * * *
757 {001 {} {{{} { 11224466 }} }}
759 {005 {} {{{} 00000000000000.0} }}
760 {008 {} {{{} {910710c19910701nju 00010 eng }} }}
761 {010 { } {{a { 11224466 }} }}
762 {040 { } {{a DLC} {c DLC} }}
763 {050 {00} {{a 123-xyz} }}
764 {100 {10} {{a {Jack Collins}} }}
765 {245 {10} {{a {How to program a computer}} }}
766 {260 {1 } {{a Penguin} }}
767 {263 { } {{a 8710} }}
768 {300 { } {{a {p. cm.}} }}
775 This example demonstrates how Tcl can be used to examine
776 a MARC record in the list notation.
778 The procedure <tt/extract-format/ makes an extraction of
779 fields in a MARC record based on a number of masks.
780 There are 5 parameters, <tt/r/: a
781 record in list notation, <tt/tag/: regular expression to
782 match the record tags, <tt/ind/: regular expression to
783 match indicators, <tt/field/: regular expression to
784 match fields, and finally <tt/text/: regular expression to
785 match the content of a field.
788 proc extract-format {r tag ind field text} {
790 if {[regexp $tag [lindex $line 0]] && \
791 [regexp $ind [lindex $line 1]]} {
792 foreach f [lindex $line 2] {
793 if {[regexp $field [lindex $f 0]]} {
794 if {[regexp $text [lindex $f 1]]} {
804 To match <tt/comput/ followed by any number of character(s) in the
805 245 fields in the record from the previous example, we could use:
807 set r [z.1 getMarc 1 line * * *]
809 extract-format $r 245 .. . comput
813 How to program a computer
818 The <tt/putMarc/ action does the opposite of <tt/getMarc/. It
819 copies a record in Tcl list notation to a ir set object and is
820 needed if a result-set must be updated by a Tcl modified (user-edited)
831 Copyright (c) 1995, Index Data.
833 Permission to use, copy, modify, distribute, and sell this software and
834 its documentation, in whole or in part, for any purpose, is hereby granted,
837 1. This copyright and permission notice appear in all copies of the
838 software and its documentation. Notices of copyright or attribution
839 which appear at the beginning of any file must remain unchanged.
841 2. The names of Index Data or the individual authors may not be used to
842 endorse or promote products derived from this software without specific
843 prior written permission.
845 THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT WARRANTY OF ANY KIND,
846 EXPRESS, IMPLIED, OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
847 WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
848 IN NO EVENT SHALL INDEX DATA BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
849 INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES
850 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR
851 NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
852 LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
855 <sect>About Index Data
858 Index Data is a consulting and software-development enterprise that
859 specialises in library and information management systems. Our
860 interests and expertise span a broad range of related fields, and one
861 of our primary, long-term objectives is the development of a powerful
862 information management
863 system with open network interfaces and hypermedia capabilities.
865 We make this software available free of charge, on a fairly unrestrictive
866 license; as a service to the networking community, and to further the
867 development of quality software for open network communication.
869 We'll be happy to answer questions about the software, and about ourselves
875 2200 København N&nl
883 Email: info@index.ping.dk
891 <tag>1 Ousterhout, John K.:</tag>
892 Tcl and the Tk Toolkit. Addison-Wesley Company Inc (ISBN
893 0-201-63337-X). Source and documentation
894 can be found in <tt>URL:ftp://ftp.cs.berkeley.edu/pub/tcl</tt>
896 <tag>2 Furniss, Peter:</tag>
897 RFC 1698: Octet Sequences for Upper-Layer OSI to Support
898 Basic Communications Applications.