5. Filters
5.1. Overview
The filters available are summarised below.
| Name | Purpose | 
| General: | |
| table | tabular data | 
| note | a note | 
| quote | a quotation | 
| abstract | the abstract for a paper | 
| title | title block for a memo, fax or minutes | 
| Line based: | |
| example | fixed-width text (e.g. source code) | 
| verbatim | fixed-width text, ignoring embedded symbols | 
| ascii_graphic | fixed-width text, wide enough for ASCII graphics | 
| nofill | a set of lines | 
| address | an address | 
| Components: | |
| front | front section of a document | 
| about | about section of a document | 
| appendix | change headings to appendix style | 
| plain | change headings to plain style | 
| Formatting: | |
| box | surround a region of text with a box | 
| changed | mark a block of text as changed | 
| sections | paragraphs are sections | 
| namevalues | format a set of name-value pairs (e.g. as used in a title block) | 
| sdf | apply arbitrary phrase attributes to text | 
| pod | embedded POD | 
| File processing: | |
| comment | ignore text | 
| topics | include a set of sub-topics | 
| inline | embed text into target format (e.g. HTML) | 
| script | execute text as a Perl script | 
| end | process text at the end | 
| get | extract embedded documentation | 
| Configuration: | |
| langdefs | define vgrind-like language definitions | 
| define | define a block of variables | 
| default | provide defaults for a block of variables | 
| simple | generic filter for building others | 
| datestrings | define strings used within dates | 
| Help: | |
| hlp_header | table of jumps at the top of a help topic | 
| hlp_window | contents of a help popup window | 
Further details on these are provided below.
