Table Of ContentInternet Programming with OmniMark
Internet Programming
with OmniMark
Edited by
Mark Baker
KLUWER ACADEMIC PUBLISHERS
NEW YORK / BOSTON / DORDRECHT/LONDON / MOSCOW
eBookISBN: 0-306-46989-8
Print ISBN: 0-792-37237-9
©2002 Kluwer Academic Publishers
New York, Boston, Dordrecht, London, Moscow
All rights reserved
No part of this eBook may be reproduced or transmitted in any form or by any means, electronic,
mechanical, recording, or otherwise, without written consent from the Publisher
Created in the United States of America
Visit Kluwer Online at: http://www.kluweronline.com
and Kluwer's eBookstore at: http://www.ebooks.kluweronline.com
v
Table of contents
Introduction:WhyOmniMark?...................................................................................1
The streaming programming model ............................................................................1
Impact of the Internet revolution ................................................................................2
What is a stream? ........................................................................................................3
A stream has a source and a destination .................................................................3
A stream has movement .........................................................................................4
A stream has structure ............................................................................................4
Streams are of unknown length ..................................................................................5
A streaming programming language ...........................................................................5
Source and destination abstraction .........................................................................5
High level data scanning features ...........................................................................6
High level context management ............................................................................. 6
Placeholder capability .............................................................................................6
Data structures where required ...............................................................................7
Broad-based connectivity........................................................................................ 7
vi Internet Programmingwith OmniMark
Co-routine support ............................................................................................... 8
Robust high level server programming support .................................................. 8
The benefits of streaming programming .................................................................. 8
Performance..........................................................................................................9
Robustness ...........................................................................................................9
Productivity..........................................................................................................10
What are streaming programming languages good for? .......................................... 10
Is streaming programming a low-level approach?...................................................11
Are there any other streaming programminglanguages? .........................................11
Streaming languages vs . object-oriented languages ...............................................11
About this book ........................................................................................................12
1:Helloworld..............................................................................................................15
Hello World CGI.................................................................................................17
Hello World server ..............................................................................................18
Writing“Hello World” to a file .............................................................................20
Technique.................................................................................................................... 20
The universal output mechanism .........................................................................20
Managing output destinations with output scopes ............................................... 21
Streams.................................................................................................................23
Directing output to multiple destinations.............................................................24
Line end and network protocols ...............................................................................26
Syntax...........................................................................................................................27
General OmniMark syntax rules ..............................................................................27
Keywords................................................................................................................28
process......................................................................................................................28
output.......................................................................................................................28
stream......................................................................................................................28
using output as ..................................................................................................... 28
local..........................................................................................................................29
open.........................................................................................................................29
#current-output........................................................................................................29
#process-output........................................................................................................29
"%n"......................................................................................................................... 29
Table ofcontents vii
| | ............................................................................................................................29
Review........................................................................................................................30
Exercises....................................................................................................................30
2: Converting text to HTML ........................................................................................31
Technique ...................................................................................................................34
Establishing sources with “using input as” ............................................................34
Scanning the input stream ..........................................................................................34
Setting traps for data using find rules ....................................................................35
Rules and the structure of OmniMark programs....................................................37
Watch and learn .....................................................................................................38
Establishing sources directly .................................................................................39
Syntax .........................................................................................................................39
#args .......................................................................................................................39
#current-input.............................................................................................................40
submit.....................................................................................................................40
using input as .........................................................................................................40
find .........................................................................................................................40
Review ........................................................................................................................40
Exercises .....................................................................................................................41
3: Converting an ASCII table to HTML...........................................................43
Technique ....................................................................................................................45
Syntax.........................................................................................................................47
Literal strings ..................................... ........................................................................47
line-start......................................................................................................................48
Occurrence indicators .............................................................................................48
Groups....................................................................................................................48
Review........................................................................................................................49
Exercises .....................................................................................................................49
viii Internet Programming with OmniMark
4:Findinglinksinaweb page...........................................................................51
Technique..........................................................................................................................52
A sponge rule ................................................................................................................52
Using character classes .................................................................................................53
Capturing matched data: Pattern variables ...................................................................55
Finding data in context ...........................................................................................55
Case insensitive pattern matching.........................................................................57
Capturing partial patterns .......................................................................................57
More on character classes ......................................................................................58
Built-in character classes .........................................................................................58
User defined character classes ...............................................................................59
Using macros to encapsulate character classes ............................................................61
Using macros to encapsulate common patterns ...........................................................61
Syntax.......................................................................................................................62
patternvariableassignmentoperator(=>)......................................................................62
User defined character classes ...............................................................................63
ul..........................................................................................................................63
lookahead.................................................................................................................. 64
Review............................................................................................................................ 64
Exercises........................................................................................................................ 64
5: Displaying the CGI environment variables ............................................................67
Technique......................................................................................................................69
Reading data from the CGI interface ...................................................................69
Using shelves ............................................................................................................70
Repeating over a shelf .............................................................................................71
Retrieving a key ........................................................................................................71
Escaping markup characters when generating HTML .............................................. 71
Syntax.............................................................................................................................72
variable.....................................................................................................................72
repeat over ................................................................................................................72
key of .........................................................................................................................72
Review............................................................................................................................73
Exercises........................................................................................................................73
Table of contents ix
6: Disaster countdown .......................................................................................75
Technique................................................................................................................78
Retrieving specific items from a shelf ................................................................78
A CGI program with multiple modes ..................................................................79
Pulling values out of a string ..............................................................................80
Converting a number to text for output ...............................................................81
Turning off input buffering .................................................................................82
Syntax...................................................................................................................... 82
shelves................................................................................................................82
has key................................................................................................................. 83
format operator (%)............................................................................................83
do when..............................................................................................................84
do scan ....................................................................................................................84
match..................................................................................................................85
Review....................................................................................................................85
Exercises.....................................................................................................................86
7: Hit counter ...........................................................................................................87
Technique................................................................................................................88
The integer data type ...........................................................................................89
Setting the value of a data destination ................................................................89
Streams as strings ...............................................................................................90
Syntax.....................................................................................................................91
set........................................................................................................................91
integer..................................................................................................................91
initial....................................................................................................................91
increment.............................................................................................................92
Review.....................................................................................................................92
Exercises..................................................................................................................92
x Internet Programmingwith OmniMark
8: Database to XML ...................................................................................................93
Technique................................................................................................................94
Accessingdatabases............................................................................................ 94
GeneratingXML.................................................................................................95
Handling errors ...................................................................................................96
Using always to ensure a valid document is returned ........................................97
Syntax.....................................................................................................................97
catch....................................................................................................................98
#external-exception.............................................................................................98
number of ............................................................................................................99
dbOpenODBC.....................................................................................................99
dbQuery...............................................................................................................100
dbFieldValue.......................................................................................................100
dbRecordMove....................................................................................................100
dbRecordExists....................................................................................................101
always..................................................................................................................102
number of ............................................................................................................102
halt.......................................................................................................................102
Review....................................................................................................................102
Exercises ................................................................................................................103
9: A game of hangman ...............................................................................................105
Technique................................................................................................................109
Scanning as a programming technique ...............................................................109
Flow control in a streaming program ..................................................................111
Using do scan for flow control ...........................................................................111
Encapsulating logic with functions .....................................................................113
Using exceptions for exceptional cases .............................................................. 113
Guarding statements ...........................................................................................115
Basic error reporting ...........................................................................................115
Using reopen to append data to a file .................................................................. 116
Syntax...................................................................................................................... 117
reopen..................................................................................................................117
formatitems.........................................................................................................117
#program-error ....................................................................................................118
Tableofcontents xi
when and unless ............................................................................................................118
repeat scan .......................................................................................................................119
any**........................................................................................................................119
= | .............................................................................................................................120
declare catch ............................................................................................................ 121
catch.........................................................................................................................121
throw........................................................................................................................121
~ (identity) ..............................................................................................................122
drop (and take) .........................................................................................................122
modulo..................................................................................................................... 122
define function ......................................................................................................... 123
matches..................................................................................................................... 123
UTIL_rand...............................................................................................................124
global.......................................................................................................................124
Review.........................................................................................................................124
Exercises......................................................................................................................124
10: Using formatting templates ......................................................................................127
Technique....................................................................................................................128
An optimized bucket match ....................................................................................129
Using an argument file to parameterize a program .................................................129
Centralizing template processing ........................................................................... 131
The template processing function ........................................................................... 131
Handling template errors ........................................................................................ 133
Syntax.......................................................................................................................... 134
define function (with arguments) ........................................................................... 134
has key ...................................................................................................................136
key of ..................................................................................................................... 136
set new ................................................................................................................... 136
Review....................................................................................................................... 137
Exercises....................................................................................................................138
