### 2.1.7 Notation and Basic Assumptions

Throughout the tutorial and reference books, the consistent notation is used to mark keywords of the scene description language, command line switches, INI file keywords and file names. All POV-Ray scene descriptionlanguage keywords, punctuation and command-line switches are mono-spaced. For example `sphere`, `4.0 * sin(45.0)` or `+W640 +H480`. Syntax descriptions are mono-spaced and all caps. For example required syntax items are written like `SYNTAX_ITEM`, while optional syntax items are written in square braces like `[SYNTAX_ITEM]`. If one or more syntax items are required, the ellipsis will be appended like `SYNTAX_ITEM...`. In case zero or more syntax items are allowed, the syntax item will be written in square braces with appended ellipsis like `[SYNTAX_ITEM...]`. A float value or expression is written mixed case like `Value_1`, while a vector value or expression is written in mixed case in angle braces like `<Value_1>`. Choices are represented by a vertical bar between syntax items. For example a choice between three items would be written as `ITEM1 | ITEM2 | ITEM3`. Further, a certain lists and arrays also require square braces as part of the language rather than the language description. When square braces are required as part of the syntax, they will be separated from the contained syntax item specification with a spaces like `[ ITEM ]`.

Note: 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 (`/`), 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 there is no way to escape it. Here are some assumptions we make...

1. You installed POV-Ray in the "`C:\POVRAY36`" directory. For MS-Dos this is probably true but for Unix it might be "`/usr/povray3`", or for Windows it might be "`C:\Program Files\POV-Ray for Windows v3.6`", for Mac it might be "`MyHD:Apps:POV-Ray 36:`", or you may have used some other drive or directory. So if we tell you that "Include files are stored in the `\povray36\include` directory," we assume you can translate that to something like "`::POVRAY36:INCLUDE`" or "`C:\Program Files\POV-Ray for Windows v3.6\include`" or whatever is appropriate for your platform, operating system and installation.
2. 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.
3. 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 "Setting POV-Ray Options" we assume you can click, scroll, browse, flip pages or whatever to get there.