Difference between revisions of "Reference:Notation and Basic Assumptions"

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<p>Throughout the tutorial and reference books, a consistent notation is used to mark keywords of the scene description language, command line switches, INI file keywords and file names.</p>
+
<p>Throughout the tutorial and reference sections, a consistent notation is used to mark keywords of the scene description language, command line switches, INI file keywords and file names.</p>
 
<p><strong>For example:</strong></p>
 
<p><strong>For example:</strong></p>
 
<p>Scene description language keywords and command-line switches:</p>
 
<p>Scene description language keywords and command-line switches:</p>
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</ul>
 
</ul>
  
<p>Alternatives are represented by a vertical bar between syntax items; exactly one of the listed items must be present:</p>
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<p>Choices are represented by a vertical bar between syntax items:</p>
 
<ul class="index">
 
<ul class="index">
 
   <li><code>ITEM1 | ITEM2 | ITEM3</code></li>
 
   <li><code>ITEM1 | ITEM2 | ITEM3</code></li>
 
</ul>
 
</ul>
  
<p>Arbitrary order is represented by an ampersand between syntax items:</p>
+
<p>Certain lists and arrays also require square braces as part of the language rather than the language description:</p>
 
<ul class="index">
 
<ul class="index">
   <li><code>ITEM1 & ITEM2 & ITEM3</code></li>
+
   <li><code>[ ITEM ]</code></li>
</ul>
 
 
 
<p>Fixed order is represented by simple juxtaposition of syntax items:</p>
 
<ul class="index">
 
  <li><code>ITEM1 ITEM2 ITEM3</code></li>
 
 
</ul>
 
</ul>
  
<p>The above notations can also appear in various combinations; parentheses are used to resolve ambiguities. For instance, the following notation would indicate that the optional items ITEM1 and ITEM2, as well as either ITEM3A or ITEM3B, may appear in any order:</p>
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<p>{{New}} in version 3.8 these additional annotations appear throughout the documentation:</p>
 
<ul class="index">
 
<ul class="index">
   <li><code>[ITEM1] & [ITEM2] & (ITEM3A | ITEM3B)</code></li>
+
   <li>{{Change}} followed by a version reference and designates a behavior change</li>
</ul>
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  <li>{{New}} followed by a version reference to designate feature addition</li>
 
+
  <li>The generic form <code>vX.y.z</code> of the version number and it's short form <code>vX.y</code> currently v3.8.0 and
<p class="Note"><strong>Note:</strong> The ampersand notation to denote arbitrary order is just being phased in; some syntax descriptions may still use juxtaposition, regardless of whether the order of items is irrelevant or not; please be aware that those are (or at least should be) exceptions.</p>
+
    v3.8 respectively</li>
 
 
<p>Certain lists and arrays also require square braces as part of the language rather than the language description:</p>
 
<ul class="index">
 
  <li><code>[ ITEM ]</code></li>
 
 
</ul>
 
</ul>
  
<p class="Note"><strong>Note:</strong> POV-Ray is a command-line program on Unix and other text-based operating systems and is menu-driven on Windows and Macintosh platforms. Some of these operating systems use folders to store files while others use directories. Some separate the folders and sub-folders with a slash character (<code>/</code>), back-slash character (<code>\</code>), or others. </p>
+
<p class="Note"><strong>Note:</strong> POV-Ray is available as a command-line program on some platforms and as a GUI on others. Some of these platforms use folders to store files while others use directories. Some separate the folders and sub-folders with a slash character (<code>/</code>), back-slash character (<code>\</code>), or others. We have tried to make this documentation as generic as possible but sometimes we have to refer to folders, files, options etc., and rather than try to represent all possible combinations
<p>We have tried to make this documentation as generic as possible but sometimes we have to refer to folders, files, options etc. and there is noway to escape it. Here are some assumptions we make...</p><ol><li> You installed POV-Ray in the <code>C:\POVRAY36</code> directory. For MS-Dos this is probably true but for Unix it might be <code>/usr/povray3</code>, or for Windows it might be<code> C:\Program Files\POV-Ray for Windows v3.6</code>, for Mac it might be <code>MyHD:Apps:POV-Ray 36:</code>, or you may have used some other drive or directory. So if we tell you that Include files are stored in the <code>\povray36\include</code> directory, we assume you can translate that to something like<code>::POVRAY36:INCLUDE</code> or <code>C:\Program Files\POV-Ray for Windows v3.6\include</code> or whatever is appropriate for your platform, operating system and installation.<li> POV-Ray uses INI files and/or command-line switches (if available) to choose options in all versions, but Windows and Mac also use dialog boxes or menu choices to set options. We will describe options assuming you are using switches or INI files when describing what the options do. We have taken care to use the same terminology in designing menus and dialogs as we use in describing switches or INI keywords. See your version-specific documentation on menu and dialogs.<li> Some of you are reading this using a help-reader, built-in help,web-browser, formatted printout, or plain text file. We assume you know how to get around in which ever medium you are using. We will say See the chapter on <!--<linkto "Setting POV-Ray Options">Setting POV-Ray Options</linkto>--->[[Documentation:Tutorial Section 2.2#Setting POV-Ray Options|Setting POV-Ray Options]] we assume you can click, scroll, browse, flip pages or whatever to get there.</ol>
+
we sometimes simplify the documentation by referring to a hypothetical 'standard installation' of POV-Ray upon a Microsoft Windows computer.
 +
</p>
 +
<p> Here are some additional assumptions to be found in the documentation:</p>
 +
<ol>
 +
<li>You installed POV-Ray in the default location for Windows, with the binaries in <code>c:\Program Files\POV-Ray\vX.y</code> and include/scene files in <code>My Documents\POV-Ray\vX.y</code>.
 +
If we say 'include files are stored in the <code>include</code> directory', we mean the directory called 'include' located immediately within the folder which was used for documents, in the above case, it would be <code>My Documents\POV-Ray\vX.y\include</code>. We assume you can translate that to something like <code>/usr/local/share/povray/vX.y/include</code> for Linux or whatever is appropriate for your platform, operating system and personal installation.
 +
<li> POV-Ray uses INI files and/or command-line switches (if available) to choose options in all versions, but some platforms (e.g. Windows) also use dialog boxes or menu choices to set options. We will describe options assuming you are using switches or INI files when describing what the options do, as it is consistent across all platforms (all GUI versions of POV-Ray also provide a means of accepting command-line options and reading INI files from within the GUI - generally speaking, the menus and dialogs just provide
 +
an easier means of doing the same thing).
 +
<li>You may be reading this documentation using an operating-system specific help program, web browser, physical printout, PDF viewer, or text editor. We assume you know how to get around in which ever medium you are using. If we say &quot;See the chapter on <!--<linkto "Setting POV-Ray Options">Setting POV-Ray Options</linkto>--->[[Documentation:Tutorial Section 2.2#Setting POV-Ray Options|Setting POV-Ray Options]]&quot; we assume you can click, scroll, browse, flip pages or whatever to get there.</ol>

Latest revision as of 15:58, 4 July 2017

Throughout the tutorial and reference sections, a consistent notation is used to mark keywords of the scene description language, command line switches, INI file keywords and file names.

For example:

Scene description language keywords and command-line switches:

  • sphere, 4.0 * sin(45.0)
  • +W640 +H480

Syntax, optional syntax, multiple syntax, and zero or more syntax items allowed respectively:

  • SYNTAX_ITEM
  • [SYNTAX_ITEM]
  • SYNTAX_ITEM...
  • [SYNTAX_ITEM...]

A float value or expression, and a vector value or expression:

  • Value_1
  • <Value_1>

Choices are represented by a vertical bar between syntax items:

  • ITEM1 | ITEM2 | ITEM3

Certain lists and arrays also require square braces as part of the language rather than the language description:

  • [ ITEM ]

New in version 3.8 these additional annotations appear throughout the documentation:

  • Change followed by a version reference and designates a behavior change
  • New followed by a version reference to designate feature addition
  • The generic form vX.y.z of the version number and it's short form vX.y currently v3.8.0 and v3.8 respectively

Note: POV-Ray is available as a command-line program on some platforms and as a GUI on others. Some of these platforms use folders to store files while others use directories. Some separate the folders and sub-folders with a slash character (/), back-slash character (\), or others. We have tried to make this documentation as generic as possible but sometimes we have to refer to folders, files, options etc., and rather than try to represent all possible combinations we sometimes simplify the documentation by referring to a hypothetical 'standard installation' of POV-Ray upon a Microsoft Windows computer.

Here are some additional assumptions to be found in the documentation:

  1. You installed POV-Ray in the default location for Windows, with the binaries in c:\Program Files\POV-Ray\vX.y and include/scene files in My Documents\POV-Ray\vX.y. If we say 'include files are stored in the include directory', we mean the directory called 'include' located immediately within the folder which was used for documents, in the above case, it would be My Documents\POV-Ray\vX.y\include. We assume you can translate that to something like /usr/local/share/povray/vX.y/include for Linux or whatever is appropriate for your platform, operating system and personal installation.
  2. POV-Ray uses INI files and/or command-line switches (if available) to choose options in all versions, but some platforms (e.g. Windows) also use dialog boxes or menu choices to set options. We will describe options assuming you are using switches or INI files when describing what the options do, as it is consistent across all platforms (all GUI versions of POV-Ray also provide a means of accepting command-line options and reading INI files from within the GUI - generally speaking, the menus and dialogs just provide an easier means of doing the same thing).
  3. You may be reading this documentation using an operating-system specific help program, web browser, physical printout, PDF viewer, or text editor. We assume you know how to get around in which ever medium you are using. If we say "See the chapter on Setting POV-Ray Options" we assume you can click, scroll, browse, flip pages or whatever to get there.