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* NKSP language tour: minor correction about the form
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1 <html>
2 <head>
3 <meta name="author" content="Christian Schoenebeck">
4 <title>NKSP Language</title>
5 <meta name="description" content="Introduction to the NKSP real-time instrument script language.">
6 </head>
7 <body>
8 <p>
9 This document intends to give you a compact introduction and overview to
10 the NKSP real-time instrument script language, so you can start writing
11 your own instrument scripts in short time. It concentrates on describing
12 the script language. If you rather want to learn how to modify and
13 attach scripts to your sounds, then please refer to the gigedit manual for
14 <a href="gigedit_scripts.html">how to manage instrument scripts with gigedit</a>
15 for Gigasampler/GigaStudio format sounds, or refer to the SFZ opcode
16 <code lang="sfz">script</code> for attaching NKSP scripts with
17 SFZ format sounds.
18 </p>
19
20 <h3>At a Glance</h3>
21 <p>
22 <img src="nksp_file.png" style="height:111px; margin-right:12px;">
23 NKSP stands for "is <b>N</b>ot <b>KSP</b>", which denotes its distinction
24 to an existing proprietary language called <i>KSP</i>.
25 NSKP is a script language specifically designed to write real-time capable
26 software extensions to LinuxSampler's sampler engines that can be bundled
27 individually with sounds by sound designers themselves.
28
29 Instead of defining a completely new script language, NKSP is leaned on
30 that mentioned properiatary script language. The biggest advantage is that
31 sound designers and musicians can leverage the huge amount of existing KSP
32 scripts which are already available for various purposes on the Internet,
33 instead of being forced to write all scripts from scratch in a completely
34 different language.
35 </p>
36 <p>
37 That also means however that there are some differences between those two
38 languages. Some extensions have been added to the NKSP core language to
39 make it a bit more convenient and less error prone to write scripts, and
40 various new functions had to be added due to the large difference of the
41 sampler engines and their underlying sampler format. Efforts have been
42 made though to make NKSP as much compatible to KSP as possible.
43 The NKSP documentation will emphasize individual differences in
44 the two languages and function implementations wherever they may occur, to
45 give you immediate hints where you need to take care of regarding
46 compatibility issues when writing scripts that should be spawned on both
47 platforms.
48 </p>
49 <p>
50 Please note that the current focus of NKSP is the sound controlling aspect
51 of sounds. At this point there is no support for the graphical user
52 interface function set of KSP in NKSP.
53 </p>
54
55 <h2>Event Handlers</h2>
56 <p>
57 NKSP is an event-driven language. That means you are writing so called
58 <i>event handlers</i> which define what the sampler shall do on individual
59 events that occur, while using the sound the script was bundled with.
60 An event handler in general looks like this:
61 </p>
62 <code lang="nksp">
63 on ??event-name??
64
65 ??statements??
66
67 end on
68 </code>
69 <p>
70 There are currently four events available:
71 </p>
72 <table>
73 <tr>
74 <th>Event Type</th> <th>Description</th>
75 </tr>
76 <tr>
77 <td><code>on note</code></td> <td>This event handler is executed when a new note was triggered, i.e. when hitting a key on a MIDI keyboard.</td>
78 </tr>
79 <tr>
80 <td><code>on release</code></td> <td>This event handler is executed when a new note was released, i.e. when releasing a key on a MIDI keyboard.</td>
81 </tr>
82 <tr>
83 <td><code>on controller</code></td> <td>This event handler is executed when a MIDI control change event occurred. For instance when turning the modulation wheel at a MIDI keyboard.</td>
84 </tr>
85 <tr>
86 <td><code>on init</code></td> <td>Executed only once, as very first event handler, right after the script had been loaded. This code block is usually used to initialize variables in your script with some initial, useful data.</td>
87 </tr>
88 </table>
89 <p>
90 You are free to decide for which ones of those event types you are going to
91 write an event handler for. You can write an event handler for only one
92 event type or write event handlers for all of those event types. Also
93 dependent on the respective event type, there are certain things you can
94 do and things which you can't do. But more on that later.
95 </p>
96
97 <h3>Note Events</h3>
98 <p>
99 As a first example, the following tiny script will print a message to your
100 terminal whenever you trigger a new note with your MIDI keyboard.
101 </p>
102 <code>
103 on note
104 message("A new note was triggered!")
105 end on
106 </code>
107 <p>
108 Probably you are also interested to see which note you triggered exactly.
109 The sampler provides you a so called
110 <i title="A script variable which is provided by the sampler and which has a very specific purpose which you cannot override for other purposes.">
111 built-in variable
112 </i>
113 called <code>$EVENT_NOTE</code> which reflects the note number
114 (as value between 0 and 127) of the note that has just been triggered. Additionally
115 the built-in variable <code>$EVENT_VELOCITY</code> provides you the
116 velocity value (also between 0 and 127) of the note event.
117 </p>
118 <code>
119 on note
120 message("Note " & $EVENT_NOTE & " was triggered with velocity " & $EVENT_VELOCITY)
121 end on
122 </code>
123 <p>
124 The <code>&</code> character concatenates text strings with each other.
125 In this case it is also automatically converting the note number into a
126 text string.
127 </p>
128 <note class="important">
129 The message() function is not appropriate for being used with your final
130 production sounds, since it can lead to audio dropouts.
131 You should only use the message() function to try out things, and to spot
132 and debug problems with your scripts.
133 </note>
134
135 <h3>Release Events</h3>
136 <p>
137 As counter part to the <code>note</code> event handler, there is also the
138 <code>release</code> event handler, which is executed when a note was
139 released. This event handler can be used similarly:
140 </p>
141 <code>
142 on release
143 message("Note " & $EVENT_NOTE & " was released with release velocity " & $EVENT_VELOCITY)
144 end on
145 </code>
146 <p>
147 Please note that you can hardly find MIDI keyboards which support release
148 velocity. So with most keyboards this value will be 127.
149 </p>
150
151 <h3>Controller Events</h3>
152 <p>
153 Now let's extend the first script to not only show note-on and note-off
154 events, but also to show a message whenever
155 you use a MIDI controller (i.e. modulation wheel, sustain pedal, etc.).
156 </p>
157 <code>
158 on note
159 message("Note " & $EVENT_NOTE & " was triggered with velocity " & $EVENT_VELOCITY)
160 end on
161
162 on release
163 message("Note " & $EVENT_NOTE & " was released with release velocity " & $EVENT_VELOCITY)
164 end on
165
166 on controller
167 message("MIDI Controller " & $CC_NUM " changed its value to " & %CC[$CC_NUM])
168 end on
169 </code>
170 <p>
171 It looks very similar to the note event handlers. <code>$CC_NUM</code>
172 reflects the MIDI controller number of the MIDI controller that had been
173 changed and <code>%CC</code> is a so called <i>array variable</i>, which not only
174 contains a single number value, but instead it contains several values at
175 the same time. The built-in <code>%CC</code> array variable contains the current
176 controller values of all 127 MIDI controllers. So <code>%CC[1]</code> for
177 example would give you the current controller value of the modulation
178 wheel, and therefore <code>%CC[$CC_NUM]</code> reflects the new controller
179 value of the controller that just had been changed.
180 </p>
181 <p>
182 There is some special aspect you need to be aware about: in contrast to the MIDI standard,
183 monophonic aftertouch (a.k.a. channel pressure) and pitch beend wheel are
184 handled by NKSP as if they were regular MIDI controllers. So a value change
185 of one of those two triggers a regular <code>controller</code> event handler
186 to be executed. To obtain the current aftertouch value you can use
187 <code>%CC[$VCC_MONO_AT]</code>, and to get the current pitch bend wheel
188 value use <code>%CC[$VCC_PITCH_BEND]</code>.
189 </p>
190
191 <h3>Script Load Event</h3>
192 <p>
193 As the last one of the four event types available with NKSP, the following
194 is an example of an <code>init</code> event handler.
195 </p>
196 <code>
197 on init
198 message("This script has been loaded and is ready now!")
199 end on
200 </code>
201 <p>
202 You might think, that this is probably a very exotic event. Because in
203 fact, this "event" is only executed once for your script: exactly when
204 the script was loaded by the sampler. This is not an unimportant event
205 handler though. Because it is used to prepare your script for various
206 purposes. We will get more about that later.
207 </p>
208
209 <h2>Comments</h2>
210 <p>
211 Let's face it: software code is sometimes hard to read, especially when you
212 are not a professional software developer who deals with such kinds of
213 things every day. To make it more easy for you to understand, what you
214 had in mind when you wrote a certain script three years ago, and also if
215 some other developer might need to continue working on your scripts one
216 day, you should place as many comments into your scripts as possible. A
217 comment in NKSP is everything that is nested into a an opening and closing
218 pair of curly braces.
219 </p>
220 <code>{ This is a comment. }</code>
221 <p>
222 You cannot only use this to leave some human readable explanations here
223 and there, you might also use such curly braces to quickly disable parts
224 of your scripts for a moment, i.e. when debugging certain things.
225 </p>
226 <code>
227 on init
228 { The following will be prompted to the terminal when the sampler loaded this script. }
229 message("My script loaded.")
230
231 { This code block is commented out, so these two messages will not be displayed }
232 {
233 message("Another text")
234 message("And another one")
235 }
236 end on
237 </code>
238
239 <h2>Variables</h2>
240 <p>
241 In order to be able to write more complex and more useful scripts, you
242 also need to remember some data somewhere for being able to use that
243 data at a later point. This can be done by using
244 <i title="A variable is a storage location paired with an associated symbolic name.">
245 variables
246 </i>.
247 We already came across some <i>built-in variables</i>, which are already
248 defined by the sampler for you. To store your own data you need to declare
249 your own <i>user variables</i>, which has the following form:
250 </p>
251 <p>
252 <code>declare $??variable-name?? := ??initial-value??
253 </p>
254 <p>
255 The left hand side's <code>??variable-name??</code> is an arbitrary name
256 you can chose for your variable. That name might consist of English
257 letters A to Z (lower and upper case), digits (<code>0</code> to <code>9</code>),
258 and the underscore character "<code>_</code>".
259 Variable names must be unique. So you can neither declare several variables
260 with the same name, nor can you use a name for your variable that is
261 already been reserved by <i>built-in variables</i>.
262 The right hand side's <code>??initial-value??</code> is simply the first
263 value the variable should store right after it was created. You can also
264 omit that.
265 </p>
266 <p>
267 <code>declare $??variable-name??
268 </p>
269 <p>
270 In that case the sampler will automatically assign <code>0</code> for you
271 as the variable's initial value. This way we could for example count the
272 total amount of notes triggered.
273 </p>
274 <code>
275 on init
276 declare $numberOfNotes := 0
277 end on
278
279 on note
280 $numberOfNotes := $numberOfNotes + 1
281
282 message("This is the " & $numberOfNotes & "th note triggered so far.")
283 end on
284 </code>
285 <p>
286 In the <code>init</code> event handler we create our own variable
287 <code>$numberOfNotes</code> and assign <code>0</code> to it as its
288 initial value. Like mentioned before, that initial assignment is optional.
289 In the <code>note</code> event handler we then increase the
290 <code>$numberOfNotes</code> variable by one, each time a new note was
291 triggered and then print a message to the terminal with the current total
292 amount of notes that have been triggered so far.
293 </p>
294 <note>
295 NKSP allows you to declare variables in all event handlers, however if
296 you want to keep compatibility with KSP, then you should only
297 declare variables in <code>init</code> event handlers.
298 </note>
299
300 <h3>Variable Types</h3>
301 <p>
302 There are currently three different variable types, which you can easily
303 recognize upon their first character.
304 </p>
305 <table>
306 <tr>
307 <th>Variable Form</th> <th>Data Type</th> <th>Description</th>
308 </tr>
309 <tr>
310 <td><code>$??variable-name??</code></td> <td>Integer Scalar</td> <td>Stores one single integer number value.</td>
311 </tr>
312 <tr>
313 <td><code>%??variable-name??</code></td> <td>Integer Array</td> <td>Stores a certain amount of integer number values.</td>
314 </tr>
315 <tr>
316 <td><code>@??variable-name??</code></td> <td>String</td> <td>Stores one text string.</td>
317 </tr>
318 </table>
319 <p>
320 So the first character just before the actual variable name, always
321 denotes the data type of the variable. Also note that all variable types
322 share the same variable name space. That means you cannot declare a
323 variable with a name that has already been used to declare a variable of
324 another variable type.
325 </p>
326
327 <h3>Array Variables</h3>
328 <p>
329 We already used the first two variable types. However we have not seen yet
330 how to declare such array variables. This is the common declaration form
331 for creating your own array variables.
332 </p>
333 <code>
334 on init
335 declare %??variable-name??[??array-size??] := ( ??list-of-values?? )
336 end on
337 </code>
338 <p>
339 So let's say you wanted to create an array variable with the first 12
340 prime numbers, then it might look like this.
341 </p>
342 <code>
343 on init
344 declare %primes[12] := ( 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37 )
345 end on
346 </code>
347 <p>
348 Like with integer variables, assigning some initial values with
349 <code>??list-of-values??</code> is optional. The array
350 declaration form without initial value assignment looks like this.
351 </p>
352 <code>
353 on init
354 declare %??variable-name??[??array-size??]
355 end on
356 </code>
357 <p>
358 When you omit that initial assignment, then all numbers of that array will
359 automatically be initialized with <code>0</code> each. With array
360 variables however, it is always mandatory to provide
361 <code>??array-size??</code> with an array
362 variable declaration, so the sampler can create that array with the
363 requested amount of values when the script is loaded. In contrast to many
364 other programming languages, changing that amount of values of an array
365 variable is not possible after the variable had been declared. That's due
366 to the fact that this language is dedicated to real-time applications, and
367 changing the size of an array variable at runtime would harm real-time
368 stability of the sampler and thus could lead to audio dropouts. So NKSP
369 does not allow you to do that.
370 </p>
371
372
373 <h3>String Variables</h3>
374 <p>
375 You might also store text with variables. These are called <i>text string
376 variables</i>, or short: <i>string variables</i>. Let's skip the common declaration
377 form of string variables and let us modify a prior example to just use
378 such kind of variable.
379 </p>
380 <code>
381 on init
382 declare $numberOfNotes
383 declare @firstText := "This is the "
384 declare @secondText
385 end on
386
387 on note
388 $numberOfNotes := $numberOfNotes + 1
389 @secondText := "th note triggered so far."
390 message(@firstText & $numberOfNotes & @secondText)
391 end on
392 </code>
393 <p>
394 It behaves exactly like the prior example and shall just give you a
395 first idea how to declare and use string variables.
396 </p>
397 <note class="important">
398 Like with the message() function, you should not use string variables
399 with your final production sounds, since it can lead to audio dropouts.
400 You should only use string variables to try out things, and to spot
401 and debug problems with your scripts.
402 </note>
403
404 <h3>Variable Scope</h3>
405 <p>
406 By default, all variables you declare with NKSP are
407 <i title="A variable that is accessible throughout an entire script.">
408 global variables
409 </i>. That means every event handler can access the data of such a global
410 variable. Furthermore, each instance of an event handler accesses the same
411 data when it is referencing that variable. And the latter fact can be a
412 problem sometimes, which we will outline next.
413 </p>
414 <p>
415 Let's assume you wanted to write an instrument script that shall resemble
416 a simple delay effect. You could do that by writing an note event handler
417 that automatically triggers several new notes for each note being
418 triggered on a MIDI keyboard. The following example demonstrates how that
419 could be achieved.
420 </p>
421 <note>
422 You need at least LinuxSampler 2.0.0.svn2 or higher for the following
423 example to work as described and as expected. Refer to the notes of the
424 <code>wait()</code> function reference documentation for more
425 informations about this issue.
426 </note>
427 <code>
428 on init
429 { The amount of notes to play }
430 declare const $delayNotes := 4
431 { Tempo with which the new notes will follow the orignal note }
432 declare const $bpm := 90
433 { Convert BPM to microseconds (duration between the notes) }
434 declare const $delayMicroSeconds := 60 * 1000000 / $bpm
435 { Just a working variable for being used with the while loop below }
436 declare $i
437 { For each successive note we trigger, we will reduce the velocity a bit}
438 declare $velocity
439 end on
440
441 on note
442 { First initialize the variable $i with 4 each time we enter this event
443 handler, because each time we executed this handler, the variable will be 0 }
444 $i := $delayNotes
445
446 { Loop which will be executed 4 times in a row }
447 while ($i)
448 { Calculate the velocity for the next note being triggered }
449 $velocity := 127 * $i / ($delayNotes + 1)
450 { Suspend this script for a short moment ... }
451 wait($delayMicroSeconds)
452 { ... and after that short break, trigger a new note. }
453 play_note($EVENT_NOTE, $velocity)
454 { Decrement loop counter $i by one }
455 $i := $i - 1
456 end while
457 end on
458 </code>
459 <p>
460 In this example we used a new keyword <code>const</code>. This additional
461 variable qualifier defines that we don't intend to change this variable
462 after declaration. So if you know beforehand, that a certain variable should
463 remain with a certain value, then you might use the <code>const</code>
464 qualifier to avoid that you i.e. change the value accidently when you
465 modify the script somewhere in future.
466 </p>
467 <p>
468 Now when you trigger one single note on your keyboard with that script,
469 you will hear the additional notes being triggered. And also when you
470 hit another note after a while, everything seems to be fine. However if
471 you start playing quick successive notes, you will notice something goes
472 wrong. The amount of notes being triggered by the script is now incorrect
473 and also the volume of the individual notes triggered by the script is wrong.
474 What's going on?
475 </p>
476 <p>
477 To understand the problem in the last example, let's consider what is
478 happening when executing that script exactly: Each time you play a note
479 on your keyboard, a new instance of the <code>note</code> event handler
480 will be spawned and executed by the sampler. In all our examples so far
481 our scripts were so simple, that in practice only one handler instance
482 was executed at a time. This is different in this case though. Because
483 by calling the <code>wait()</code> function, the respective handler
484 execution instance is paused for a while and in total each handler
485 instance will be executed for more than 2 seconds in this particular
486 example. As a consequence, when
487 you play multiple, successive notes on your keyboard in short time, you
488 will have several instances of the <code>note</code> event handler running
489 simultaniously. And that's where the problem starts. Because by default,
490 as said, all variables are global variables. So the handler instances
491 which are now running in parallel, are all reading and modifying the same
492 data. Thus the individual handler instances will modify the
493 <code>$i</code> and <code>$velocity</code> variables of each other, causing
494 an undesired misbehavior.
495 </p>
496 <note>
497 NKSP's built-in function <code>play_note()</code> allows you to pass
498 between one and four function arguments. For the function arguments you
499 don't provide to a <code>play_note()</code> call, NKSP will automatically
500 use default values. If you want your script to be compatible with KSP,
501 then you should always pass four arguments to that function though.
502 </note>
503
504 <h3>Polyphonic Variables</h3>
505 <p>
506 As a logical consequence of the previously described data concurrency
507 problem, it would be desirable to have each event handler instance use
508 its own variable instance, so that the individual handler instances stop
509 interfering with each other. For this purpose the so called
510 <i title="A variable which is effectively a separate variable for each event handler instance.">
511 polyphonic variable
512 </i>
513 qualifier exists with NKSP. Declaring such a variable is identical to
514 declaring a regular variable, just that you add the keyword <code>polyphonic</code>.
515 </p>
516 <code>
517 declare polyphonic $??variable-name??
518 </code>
519 <p>
520 So to fix the bug in our previous example, we simply make the variables
521 <code>$i</code> and <code>$velocity</code> polyphonic variables.
522 </p>
523 <code>
524 on init
525 { The amount of notes to play }
526 declare const $delayNotes := 4
527 { Tempo with which the new notes will follow the orignal note }
528 declare const $bpm := 90
529 { Convert BPM to microseconds (duration between the notes) }
530 declare const $delayMicroSeconds := 60 * 1000000 / $bpm
531 { Just a working variable for being used with the while loop below }
532 declare polyphonic $i { < --- NOW POLYPHONIC !!! }
533 { For each successive note we trigger, we will reduce the velocity a bit}
534 declare polyphonic $velocity { < --- NOW POLYPHONIC !!! }
535 end on
536
537 on note
538 { First initialize the variable $i with 4 each time we enter this event
539 handler, because each time we executed this handler, the variable will be 0 }
540 $i := $delayNotes
541
542 { Loop which will be executed 4 times in a row }
543 while ($i)
544 { Calculate the velocity for the next note being triggered }
545 $velocity := 127 * $i / ($delayNotes + 1)
546 { Suspend this script for a short moment ... }
547 wait($delayMicroSeconds)
548 { ... and after that short break, trigger a new note. }
549 play_note($EVENT_NOTE, $velocity)
550 { Decrement loop counter $i by one }
551 $i := $i - 1
552 end while
553 end on
554 </code>
555 <p>
556 And that's it! The script works now as intended. Now you might wonder, why
557 are variables not <i>polyphonic</i> by default? Isn't that more common and
558 wouldn't that be more safer than using global variables by default? The reason is that
559 a polyphonic variable consumes a lot more memory than a regular (global) variable.
560 That's because for each polyphonic variable, the sampler has to allocate
561 in advance (when the script is loaded) as many instances of that
562 polyphonic variable as there are maximum events
563 allowed with the sampler. So that's a lot! Considering that today's
564 computers have plenty of RAM this might be a theoretical aspect, but in the
565 end: this default scope of variables was already like this with <i>KSP</i>
566 so we are also doing it like this with NKSP for compatibility reasons.
567 </p>
568 <p>
569 Please note that the <i>polyphonic</i> qualifier only exists for integer
570 variables. So you cannot declare polyphonic string variables, nor can you
571 declare polyphonic array variables. Like in the previous explanation,
572 this is due to the fact that it would consume a huge amount of memory
573 for such variables. And with string variables and array variables, the
574 required amount of memory would be much higher than with simple integer
575 variables.
576 </p>
577 <p>
578 As summary, the following are guideline rules describing when you should
579 use the polyphonic qualifier for a certain variable. You should declare
580 a particular variable polyphonic if one (or even both) of the following two
581 conditions apply to that variable.
582 </p>
583 <ol>
584 <li>
585 If you call the <code>wait()</code> function within your event
586 handlers and the respective variable is modified and read before
587 and after at least one of the individual <code>wait()</code> calls.
588 </li>
589 <li>
590 If you have loops that might run for a very long time, while accessing
591 the respective variable in between. That's because if your script is
592 running consecutively for too long, the sampler will automatically suspend your
593 script for a while to avoid your script becoming a real-time stability
594 hazard for the sampler. Your script will then automatically be resumed
595 after a short moment by the sampler, so effectively this is similar to
596 something like an "automated" <code>wait()</code> function call by
597 the sampler.
598 </li>
599 </ol>
600 <p>
601 In all other cases you should rather use regular (global) variables instead.
602 But keep in mind that you might need to re-assign a certain value for
603 some global variables when you enter the respective event handler, just
604 like we did with <code>$i := $delayNotes</code> right from the start
605 during discussion of the previous example script.
606 </p>
607 <p>
608 There is another special aspect regarding the variable scope of polyphonic
609 variables: <code>note</code> handlers and <code>release</code> handlers of
610 the same script share the same polyphonic variable scope, that means you
611 may pass data from a particular note's <code>note</code> handler to its
612 <code>release</code> handler by using the same polyphonic variable name.
613 </p>
614
615 <h2>Control Structures</h2>
616 <p>
617 A computer is more than a calculator that adds numbers and stores them
618 somewhere. One of the biggest strength of a computer, which makes it
619 such powerful, is the ability to do different things depending on various
620 conditions. For example your computer might clean up your hard drive
621 while you are not sitting in front of it, and it might immediately stop
622 doing so when you need all its resources to cut your latest video which
623 you just shot.
624 </p>
625 <p>
626 In order to do that for you, a computer program allows you to define
627 conditions and a list of instructions the computer shall
628 perform for you under those individual conditions. These kinds of
629 software mechanisms are called <i>Control Structures</i>.
630 </p>
631
632 <h3>if Branches</h3>
633 <p>
634 The most fundamental control structure are <i>if branches</i>, which has
635 the following general form.
636 </p>
637 <code>
638 if (??condition??)
639
640 ??statements??
641
642 end if
643 </code>
644 <p>
645 The specified <code>??condition??</code> is evaluated each time script
646 execution reaches this control block. The condition can for example be
647 the value of a variable, some arithmetic expression, a function call or
648 a combination of them. In all cases the sampler expects the
649 <code>??condition??</code> expression to evaluate to some numeric
650 (or boolean) value. If the evaluated number is exactly <code>0</code> then
651 the condition is interpreted to be <i>false</i> and thus the list of
652 <code>??statements??</code> is not executed. If the evaluated value is any
653 other value than <code>0</code> then the condition is interpreted to be
654 <i>true</i> and accordingly the list of <code>??statements??</code> will be
655 executed.
656 </p>
657 <p>
658 Alternatively you might also specify a list of instructions which shall be
659 executed when the condition is <i>false</i>.
660 </p>
661 <code>
662 if (??condition??)
663
664 ??statements-when-true??
665
666 else
667
668 ??statements-when-false??
669
670 end if
671 </code>
672 <p>
673 In this case the first list of statements is executed when the
674 <code>??condition??</code> evaluated to <i>true</i>, otherwise the second
675 list of statements is executed instead.
676 </p>
677 <p>
678 Once again, let's get back to the example of counting triggered notes.
679 You might have noticed that it did not output correct English for the
680 first three notes. Let's correct this now.
681 </p>
682 <code>
683 on init
684 declare $numberOfNotes
685 declare @postfix
686 end on
687
688 on note
689 $numberOfNotes := $numberOfNotes + 1
690
691 if ($numberOfNotes == 1)
692 @postfix := "st"
693 else
694 if ($numberOfNotes == 2)
695 @postfix := "nd"
696 else
697 if ($numberOfNotes == 3)
698 @postfix := "rd"
699 else
700 @postfix := "th"
701 end if
702 end if
703 end if
704
705 message("This is the " & $numberOfNotes & @postfix & " note triggered so far.")
706 end on
707 </code>
708 <p>
709 We are now checking the value of <code>$numberOfNotes</code> before we
710 print out a message. If <code>$numberOfNotes</code> equals one, then we
711 assign the string <code>"st"</code> to the variable <code>@postfix</code>,
712 if <code>$numberOfNotes</code> equals 2 instead we assign the string
713 <code>"nd"</code> instead, if it equals 3 instead we assign
714 <code>"rd"</code>, in all other cases we assign the string
715 <code>"th"</code>. And finally we assemble the text message to be
716 printed out to the terminal on line 23.
717 </p>
718
719 <h3>Select Case Branches</h3>
720 <p>
721 The previous example now outputs the numbers in correct English. But the
722 script code looks a bit bloated, right? That's why there is a short hand
723 form.
724 </p>
725 <code>
726 select ??expression??
727
728 case ??integer-1??
729
730 ??statements-1??
731
732
733 case ??integer-2??
734
735 ??statements-2??
736
737 .
738 .
739 .
740 end select
741 </code>
742 <p>
743 The provided <code>??expression??</code> is first evaluated to an integer
744 value. Then this value is compared to the integer values of the nested
745 <code>case</code> lines. So it first compares the evaluated value of
746 <code>??expression??</code> with <code>??integer-1??</code>, then it
747 compares it with <code>??integer-2??</code>, and so on. The first integer
748 number that matches with the evaluated value of <code>??expression??</code>,
749 will be interpreted as being the current valid condition. So if
750 <code>??expression??</code> equals <code>??integer-1??</code>,
751 then <code>??statements-1??</code> will be executed, otherwise if
752 <code>??expression??</code> equals <code>??integer-2??</code>,
753 then <code>??statements-2??</code> will be executed, and so on.
754 </p>
755 <p>
756 Using a select-case construct, our previous example would look like follows.
757 </p>
758 <code>
759 on init
760 declare $numberOfNotes
761 declare @postfix
762 end on
763
764 on note
765 $numberOfNotes := $numberOfNotes + 1
766 @postfix := "th"
767
768 select $numberOfNotes
769 case 1
770 @postfix := "st"
771 case 2
772 @postfix := "nd"
773 case 3
774 @postfix := "rd"
775 end select
776
777 message("This is the " & $numberOfNotes & @postfix & " note triggered so far.")
778 end on
779 </code>
780 <note>
781 If you like, you can also put parentheses around the select expression,
782 like <code>select (??expression??)</code>. Some developers familiar with
783 other programming languages might prefer this style. However if you want
784 to keep compatibility with KSP, you should not use parentheses for
785 select expressions.
786 </note>
787 <p>
788 The amount
789 of case conditions you add to such select-case blocks is completely up
790 to you. Just remember that the case conditions will be compared one by one,
791 from top to down. The latter can be important when you define a case line
792 that defines a value range. So for instance the following example will
793 not do what was probably intended.
794 </p>
795 <code>
796 on init
797 declare $numberOfNotes
798 end on
799
800 on note
801 $numberOfNotes := $numberOfNotes + 1
802
803 select $numberOfNotes
804 case 1 to 99
805 message("Less than 100 notes triggered so far")
806 exit
807 case 1
808 message("First note was triggered!") { Will never be printed ! }
809 exit
810 case 2
811 message("Second note was triggered!") { Will never be printed ! }
812 exit
813 case 3
814 message("Third note was triggered!") { Will never be printed ! }
815 exit
816 end select
817
818 message("Wow, already the " & $numberOfNotes & "th note triggered.")
819 end on
820 </code>
821 <p>
822 You probably get the idea what this script "should" do. For the 1st note
823 it should print <code>"First note was triggered!"</code>, for the 2nd
824 note it should print <code>"Second note was triggered!"</code>, for the 3rd
825 note it should print <code>"Third note was triggered!"</code>, for the 4th
826 up to 99th note it should print <code>"Less than 100 notes triggered so far"</code>,
827 and starting from the 100th note and all following ones, it should print
828 the precise note number according to line 23. However, it doesn't!
829 </p>
830 <p>
831 To correct this problem, you need to move the first case block to the end,
832 like follows.
833 </p>
834 <code>
835 on init
836 declare $numberOfNotes
837 end on
838
839 on note
840 $numberOfNotes := $numberOfNotes + 1
841
842 select $numberOfNotes
843 case 1
844 message("First note was triggered!")
845 exit
846 case 2
847 message("Second note was triggered!")
848 exit
849 case 3
850 message("Third note was triggered!")
851 exit
852 case 1 to 99
853 message("Less than 100 notes triggered so far")
854 exit
855 end select
856
857 message("Wow, already the " & $numberOfNotes & "th note triggered.")
858 end on
859 </code>
860 <p>
861 Or you could of course fix the questioned case range from <code>case 1 to 99</code>
862 to <code>case 4 to 99</code>. Both solutions will do.
863 </p>
864 <p>
865 We also used the <i>built-in function</i> <code>exit()</code> in the
866 previous example. You can use it to stop execution at that point of your
867 script. In the previous example it prevents multiple messages to be
868 printed to the terminal.
869 </p>
870 <note class="important">
871 The <code>exit()</code> function only stops execution of the <b>current</b>
872 event handler instance! It does <b>not</b> stop execution of other
873 instances of the same event handler, nor does it stop execution of other
874 handlers of other event types, and especially it does <b>not</b> stop or
875 prevent further or future execution of your entire script! In other words,
876 you should rather see this function as a return statement, in case you are
877 familiar with other programming languages already.
878 </note>
879
880 <h3>while Loops</h3>
881 <p>
882 Another fundamental control construct of program flow are loops.
883 You can use so called
884 <i title="Repeats a given list of instructions until the defined condition turns false.">
885 while loops
886 </i>
887 with NKSP.
888 </p>
889 <code>
890 while (??condition??)
891
892 ??statements??
893
894 end while
895 </code>
896 <p>
897 A while loop is entered if the provided <code>??condition??</code>
898 expression evaluates to <i>true</i> and will then continue to execute
899 the given list of <code>??statements??</code> down to the end of the statements
900 list. The <code>??condition??</code> is re-evaluated each time execution
901 reached the end of the <code>??statements??</code> list and according to
902 that latest evaluated <code>??condition??</code> value at that point, it
903 will or will not repeat executing the statements again. If the condition
904 turned <i>false</i> instead, it will leave the loop and continue executing
905 statements that follow after the while loop block.
906 </p>
907 <p>
908 The next example will print the same message three times in a row to the
909 terminal, right after the script had been loaded by the sampler.
910 </p>
911 <code>
912 on init
913 declare $i := 3
914
915 while ($i)
916 message("Print this three times.")
917 $i := $i - 1
918 end while
919 end on
920 </code>
921 <p>
922 When the while loop is reached for the first time in this example, the
923 condition value is <code>3</code>. And as we learned before, all integer
924 values that are not <code>0</code> are interpreted as being a <i>true</i> condition.
925 Accordingly the while loop is entered, the message is printed to the
926 terminal and the variable <code>$i</code> is reduced by one. We reached
927 the end of the loop's statements list, so it is now re-evaluating the
928 condition, which is now the value <code>2</code> and thus the loop
929 instructions are executed again. That is repeated until the loop was
930 executed for the third time. The variable <code>$i</code> is now
931 <code>0</code>, so the loop condition turned finally to <i>false</i> and the
932 loop is thus left at that point and the text message was printed
933 three times in total.
934 </p>
935
936 <h3>User Functions</h3>
937 <p>
938 We already came across various built-in functions, which you may call
939 by your scripts to perform certain tasks or behavior which is already
940 provided for you by the sampler. NKSP also allows you to write your
941 own functions, which you then may call from various places of your
942 script.
943 <p>
944 </p>
945 When working on larger scripts, you
946 may notice that you easily get to the point where you may have to
947 duplicate portions of your script code, since there are certain things
948 that you may have to do again and again in different parts of your script.
949 Software developers usually try to avoid such code duplications to
950 keep the overall amount of code as small as possible, since the
951 overall amount of code would bloat quickly and would
952 make the software very hard to maintain. One way for you to avoid such
953 script code duplications with NKSP is to write so called <i>User Functions</s>.
954 </p>
955 <p>
956 Let's assume you wanted to create a simple stuttering effect. You may do so
957 like in the following example.
958 </p>
959 <code>
960 on note
961 while (1)
962 wait(200000)
963 if (not (event_status($EVENT_ID) .and. $EVENT_STATUS_NOTE_QUEUE))
964 exit()
965 end if
966 change_vol($EVENT_ID, -20000) { Reduce volume by 20 dB. }
967 wait(200000)
968 if (not (event_status($EVENT_ID) .and. $EVENT_STATUS_NOTE_QUEUE))
969 exit()
970 end if
971 change_vol($EVENT_ID, 0) { Increase volume to 0 dB. }
972 end while
973 end on
974 </code>
975 <p>
976 This script will run an endless loop for each note being triggered.
977 Every <code lang="none">200ms</code> it will turn the volume alternatingly down and
978 up to create the audible stuttering effect. After each <code lang="nksp">wait()</code>
979 call it calls <code>event_status($EVENT_ID)</code> to check whether
980 this note is still alive, and as soon as the note died, it will stop
981 execution of the script instance by calling <code>exit()</code>. The latter
982 is important in this example, because otherwise the script execution instances would
983 continue to run in this endless loop forever, even after the respectives
984 notes are gone. Which would let your CPU usage to increase with every new note
985 and would never decrease again.
986 This behavior of the sampler is not a bug, it is intended, since there may
987 also be cases where you want to do certain things by script even after the
988 respective notes are dead and gone. However as you can see, that script is
989 using the same portions of script code twice. To avoid that, you could also
990 write the same script with a user function like this:
991 </p>
992 <code>
993 function pauseMyScript
994 wait(200000)
995 if (not (event_status($EVENT_ID) .and. $EVENT_STATUS_NOTE_QUEUE))
996 exit()
997 end if
998 end function
999
1000 on note
1001 while (1)
1002 call pauseMyScript
1003 change_vol($EVENT_ID, -20000) { Reduce volume by 20 dB. }
1004 call pauseMyScript
1005 change_vol($EVENT_ID, 0) { Increase volume back to 0 dB. }
1006 end while
1007 end on
1008 </code>
1009 <p>
1010 The script became in this simple example only slightly smaller, but it also
1011 became easier to read and behaves identically to the previous solution.
1012 And in practice, with a more complex script, you can
1013 reduce the overall amount of script code a lot this way. You can choose any
1014 name for your own user functions, as long as the name is not already
1015 reserved by a built-in function. Note that for calling a user function,
1016 you must always precede the actual user function name with the
1017 <code>call</code> keyword. Likewise you may however not use the
1018 <code>call</code> keyword for calling any built-in function. So that
1019 substantially differs calling built-in functions from calling user functions.
1020 </p>
1021
1022 <h2>Operators</h2>
1023 <p>
1024 A programming language provides so called <i>operators</i> to perform
1025 certain kinds of transformations of data placed next to the operators.
1026 These are the operators available with NKSP.
1027 </p>
1028
1029 <h3>Arithmetic Operators</h3>
1030 <p>
1031 These are the most basic mathematical operators, which allow to add,
1032 subtract, multiply and divide integer values with each other.
1033 </p>
1034 <code>
1035 on init
1036 message("4 + 3 is " & 4 + 3) { Add }
1037 message("4 - 3 is " & 4 - 3) { Subtract }
1038 message("4 * 3 is " & 4 * 3) { Multiply }
1039 message("35 / 5 is " & 35 / 5) { Divide }
1040 message("35 mod 5 is " & 35 mod 5) { Remainder of Division ("modulo") }
1041 end on
1042 </code>
1043 <p>
1044 You may either use direct integer literal numbers like used in the upper
1045 example, or you can use integer number variables or integer array variables.
1046 </p>
1047
1048 <h3>Boolean Operators</h3>
1049 <p>
1050 To perform logical transformations of <i>boolean</i> data, you may use the
1051 following logical operators:
1052 </p>
1053 <code>
1054 on init
1055 message("1 and 1 is " & 1 and 1) { logical "and" }
1056 message("1 and 0 is " & 1 and 0) { logical "and" }
1057 message("1 or 1 is " & 1 or 1) { logical "or" }
1058 message("1 or 0 is " & 1 or 0) { logical "or" }
1059 message("not 1 is " & not 1) { logical "not" }
1060 message("not 0 is " & not 0) { logical "not" }
1061 end on
1062 </code>
1063 <p>
1064 Keep in mind that with logical operators shown above,
1065 all integer values other than <code>0</code>
1066 are interpreted as boolean <i>true</i> while an integer value of
1067 precisely <code>0</code> is interpreted of being boolean <i>false</i>.
1068 </p>
1069 <p>
1070 So the logical operators shown above always look at numbers at a whole.
1071 Sometimes however you might rather need to process numbers bit by bit. For
1072 that purpose the following bitwise operators exist.
1073 </p>
1074 <code>
1075 on init
1076 message("1 .and. 1 is " & 1 .and. 1) { bitwise "and" }
1077 message("1 .and. 0 is " & 1 .and. 0) { bitwise "and" }
1078 message("1 .or. 1 is " & 1 .or. 1) { bitwise "or" }
1079 message("1 .or. 0 is " & 1 .or. 0) { bitwise "or" }
1080 message(".not. 1 is " & .not. 1) { bitwise "not" }
1081 message(".not. 0 is " & .not. 0) { bitwise "not" }
1082 end on
1083 </code>
1084 <p>
1085 Bitwise operators work essentially like logical operators, with the
1086 difference that bitwise operators compare each bit independently.
1087 So a bitwise <code>.and.</code> operator for instance takes the 1st bit
1088 of the left hand's side value, the 1st bit of the right hand's side value,
1089 compares the two bits logically and then stores that result as 1st bit of
1090 the final result value, then it takes the 2nd bit of the left hand's side value
1091 and the 2nd bit of the right hand's side value, compares those two bits logically
1092 and then stores that result as 2nd bit of the final result value, and so on.
1093 </p>
1094
1095
1096 <h3>Comparison Operators</h3>
1097 <p>
1098 For branches in your program flow, it is often required to compare data
1099 with each other. This is done by using comparison operators, enumerated
1100 below.
1101 </p>
1102 <code>
1103 on init
1104 message("Relation 3 < 4 -> " & 3 < 4) { "smaller than" comparison }
1105 message("Relation 3 > 4 -> " & 3 > 4) { "greater than" comparison }
1106 message("Relation 3 <= 4 -> " & 3 <= 4) { "smaller or equal than" comparison}
1107 message("Relation 3 >= 4 -> " & 3 >= 4) { "greater or equal than" comparison}
1108 message("Relation 3 # 4 -> " & 3 # 4) { "not equal to" comparison}
1109 message("Relation 3 = 4 -> " & 3 = 4) { "is equal to" comparison}
1110 end on
1111 </code>
1112 <p>
1113 All these operations yield in a <i>boolean</i> result which could then
1114 by used i.e. with <code>if</code> or <code>while</code> loop statements.
1115 </p>
1116
1117 <h3>String Operators</h3>
1118 <p>
1119 Last but not least, there is exactly one operator for text string data;
1120 the string concatenation operator <code>&</code>, which
1121 combines two text strings with each other.
1122 </p>
1123 <code>
1124 on init
1125 declare @s := "foo" & " bar"
1126 message(@s)
1127 end on
1128 </code>
1129 <p>
1130 We have used it now frequently in various examples before.
1131 </p>
1132
1133 <h2>Preprocessor Statements</h2>
1134 <p>
1135 Similar to low-level programming languages like C, C++, Objective C
1136 and the like, NKSP supports a set of so called preprocessor statements.
1137 These are essentially "instructions" which are "executed" or rather
1138 processed, before (and only before) the script is executed by the sampler,
1139 and even before the script is parsed by the actual NKSP language parser.
1140 You can think of a preprocessor as a very primitive parser, which is the
1141 first one getting in touch with your script, it modifies the script code
1142 if requested by your preprocessor statements in the script, and then
1143 passes the (probably) modified script to the actual NKSP language parser.
1144 </p>
1145 <p>
1146 When we discussed <a href="#comments">comments</a> in NKSP scripts before,
1147 it was suggested that you might comment out certain code parts to disable
1148 them for a while during development of scripts. It was also suggested
1149 during this language tour that you should not use string variables or use
1150 the <code>message()</code> function with your final production sounds.
1151 However those are very handy things during development of your instrument
1152 scripts. You might even have a bunch of additional code in your scripts
1153 which only satisfies the purpose to make debugging of your scripts more easy,
1154 which however wastes on the other hand precious CPU time. So what do you
1155 do? Like suggested, you could comment out the respective code sections as
1156 soon as development of your script is completed. But then one day you
1157 might continue to improve your scripts, and the debugging code would be
1158 handy, so you would uncomment all the relevant code sections to get them
1159 back. When you think about this, that might be quite some work each time.
1160 Fortunately there is an alternative by using preprocessor statements.
1161 </p>
1162
1163 <h3>Set a Condition</h3>
1164 <p>
1165 First you need to set a preprocessor condition in your script. You can do
1166 that like this:
1167 </p>
1168 <code>
1169 SET_CONDITION(??condition-name??)
1170 </code>
1171 <p>
1172 This preprocessor "condition" is just like some kind of
1173 <i title="A variable which can only have two states: i.e. true or false.">
1174 boolean variable
1175 </i>
1176 which is only available to the preprocessor and by using
1177 <code>SET_CONDITION(??condition-name??)</code>, this is like setting this
1178 preprocessor condition to <i>true</i>. Like with regular script
1179 variables, a preprocessor condition name can be chosen quite arbitrarily
1180 by you. But again, there are some pre-defined preprocessor conditions
1181 defined by the sampler for you. So you can only set a condition name here
1182 which is not already reserved by a built-in preprocessor condition. Also
1183 you shall not set a condition in your script again if you have already set it
1184 before somewhere in your script. The NKSP preprocessor will ignore setting
1185 a condition a 2nd time and will just print a warning when the script is
1186 loaded, but you should take care of it, because it might be a cause for
1187 some bug.
1188 </p>
1189
1190 <h3>Reset a Condition</h3>
1191 <p>
1192 To clear a condition in your script, you might reset the condition like so:
1193 </p>
1194 <code>
1195 RESET_CONDITION(??condition-name??)
1196 </code>
1197 <p>
1198 This is like setting that preprocessor condition back to <i>false</i> again.
1199 You should only reset a preprocessor condition that way if you did set it
1200 with <code>SET_CONDITION(??condition-name??)</code> before. Trying to
1201 reset a condition that has not been set before, or trying to reset a
1202 condition that has already been reset, will both be ignored by the samlper,
1203 but again you will get a warning, and you should take care about it.
1204 </p>
1205
1206 <h3>Conditionally Using Code</h3>
1207 <p>
1208 Now what do you actually do with such preprocessor conditions? You can use
1209 them for the NKSP language parser to either
1210 </p>
1211 <ul>
1212 <li>use certain parts of your code</i>
1213 <li><b>and</b> / <b>or</b> to ignore certain parts of your code</i>
1214 </ul>
1215 <p>
1216 You can achieve that by wrapping NKSP code parts into a pair of either
1217 </p>
1218 <code>
1219 USE_CODE_IF(??condition-name??)
1220
1221 ??some-NKSP-code-goes-here??
1222
1223 END_USE_CODE
1224 </code>
1225 <p>
1226 preprocessor statements, or between
1227 </p>
1228 <code>
1229 USE_CODE_IF_NOT(??condition-name??)
1230
1231 ??some-NKSP-code-goes-here??
1232
1233 END_USE_CODE
1234 </code>
1235 <p>
1236 statements. In the first case, the NKSP code portion is used by the NKSP
1237 language parser if the given preprocessor <code>??condition-name??</code> is set
1238 (that is if condition is <i>true</i>).
1239 If the condition is not set, the NKSP code portion in between is
1240 completely ignored by the NKSP language parser.
1241 </p>
1242 <p>
1243 In the second case, the NKSP code portion is used by the NKSP
1244 language parser if the given preprocessor <code>??condition-name??</code> is <b>not</b> set
1245 (or was reset)
1246 (that is if condition is <i>false</i>).
1247 If the condition is set, the NKSP code portion in between is
1248 completely ignored by the NKSP language parser.
1249 </p>
1250 <p>
1251 Let's look at an example how to use that to define conditional debugging
1252 code.
1253 </p>
1254 <code>
1255 SET_CONDITION(DEBUG_MODE)
1256
1257 on init
1258 declare const %primes[12] := ( 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37 )
1259 declare $i
1260
1261 USE_CODE_IF(DEBUG_MODE)
1262 message("This script has just been loaded.")
1263
1264 $i := 0
1265 while ($i < num_elements(%primes))
1266 message("Prime " & $i & " is " & %primes[$i])
1267 $i := $i + 1
1268 end while
1269 END_USE_CODE
1270 end on
1271
1272 on note
1273 USE_CODE_IF(DEBUG_MODE)
1274 message("Note " & $EVENT_NOTE & " was triggered with velocity " & $EVENT_VELOCITY)
1275 END_USE_CODE
1276 end on
1277
1278 on release
1279 USE_CODE_IF(DEBUG_MODE)
1280 message("Note " & $EVENT_NOTE & " was released with release velocity " & $EVENT_VELOCITY)
1281 END_USE_CODE
1282 end on
1283
1284 on controller
1285 USE_CODE_IF(DEBUG_MODE)
1286 message("MIDI Controller " & $CC_NUM " changed its value to " & %CC[$CC_NUM])
1287 END_USE_CODE
1288 end on
1289 </code>
1290 <p>
1291 The <i>built-in function</i> <code>num_elements()</code> used above, can
1292 be called to obtain the size of an array variable at runtime.
1293 As this script looks now, the debug messages will be printed out. However
1294 it requires you to just remove the first line, or to comment out the first
1295 line, in order to disable all debug code portions in just a second:
1296 </p>
1297 <code>
1298 { Setting the condition is commented out, so our DEBUG_MODE is disabled now. }
1299 { SET_CONDITION(DEBUG_MODE) }
1300
1301 on init
1302 declare const %primes[12] := ( 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37 )
1303 declare $i
1304
1305 USE_CODE_IF(DEBUG_MODE) { Condition is not set, so this entire block will be ignored now. }
1306 message("This script has just been loaded.")
1307
1308 $i := 0
1309 while ($i < num_elements(%primes))
1310 message("Prime " & $i & " is " & %primes[$i])
1311 $i := $i + 1
1312 end while
1313 END_USE_CODE
1314 end on
1315
1316 on note
1317 USE_CODE_IF(DEBUG_MODE) { Condition is not set, no message will be printed. }
1318 message("Note " & $EVENT_NOTE & " was triggered with velocity " & $EVENT_VELOCITY)
1319 END_USE_CODE
1320 end on
1321
1322 on release
1323 USE_CODE_IF(DEBUG_MODE) { Condition is not set, no message will be printed. }
1324 message("Note " & $EVENT_NOTE & " was released with release velocity " & $EVENT_VELOCITY)
1325 END_USE_CODE
1326 end on
1327
1328 on controller
1329 USE_CODE_IF(DEBUG_MODE) { Condition is not set, no message will be printed. }
1330 message("MIDI Controller " & $CC_NUM " changed its value to " & %CC[$CC_NUM])
1331 END_USE_CODE
1332 end on
1333 </code>
1334 <p>
1335 Now you might say, you could also achieve that by declaring and using
1336 a regular NKSP variable. That's correct, but there are two major
1337 advantages by using preprocessor statements.
1338 </p>
1339 <ol>
1340 <li>
1341 <b>Saving Resources</b> -
1342 The preprocessor conditions are only processed before the script is
1343 loaded into the NKSP parser. So in contrast to using NKSP variables,
1344 the preprocessor solution does not waste any CPU time or memory
1345 resources while executing the script. That also means that variable
1346 declarations can be disabled with the preprocessor this way
1347 and thus will also safe resources.
1348 </li>
1349 <li>
1350 <b>Cross Platform Support</b> -
1351 Since the code portions filtered out by the preprocessor never make it
1352 into the NKSP language parser, those filtered code portions might also
1353 contain code which would have lead to parser errors. For example you
1354 could use a built-in preprocessor condition to check whether your script
1355 was loaded into LinuxSampler or rather into another sampler. That way
1356 you could maintain one script for both platforms: NKSP and KSP.
1357 Accordingly you could
1358 also check a built-in variable to obtain the version of the sampler in
1359 order to enable or disable code portions of your script that might
1360 use some newer script features of the sampler which don't exist in older
1361 version of the sampler.
1362 </li>
1363 </ol>
1364 <p>
1365 As a rule of thumb: if there are things that you could move from your
1366 NKSP executed programming code out to the preprocessor, then you should
1367 use the preprocessor instead for such things. And like stated above,
1368 there are certain things which you can only achieve with the preprocessor.
1369 </p>
1370
1371 <h2>What Next?</h2>
1372 <p>
1373 You have completed the introduction of the NKSP real-time instrument
1374 script language at this point. You can now dive into the details of the
1375 NKSP language by moving on to the
1376 <a href="nksp_reference.html">NKSP reference documentation</a>.
1377 Which provides you an overview and quick access to the details of all
1378 built-in functions, built-in variables and more.
1379 </p>
1380
1381 </body>
1382 </html>

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