'Additional Functionality#

HFRD Hypertext Menu Primer

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4 - Additional Functionality




LThe features described in this section allow functionality other that merelyLretrieving and displaying files, and can be easily and effectively employed from the menuing system. 

:These features largely depend on the underlying BHTS (see S5 - Glossary). For a document on BHTS, see 86 - References). $

4.1 - Search Items In Menus



LThe menuing system provides a simple text-search capability. The search is Gfor plain-text or HTML-text documents (searches on other types are not Osupported). For an HTML-text file a hit requires the selecting and reading of Lthe entire file, whereas with plain-text a section around the line in which 3the hit occured can also be selectively extracted. 

Note:

LSearching is a notoriously CPU and I/O intensive activity. Longer searches Iprogressively decrease scheduling priority by one every 10 seconds, from Inormal to zero, helping to reduce impact on any interactive users of the Mserver system. The search algorithm itself is efficient, but searching will Gtake longer on a more heavily loaded system because of this mechanism.
 

JA search item is produced by simply appending a question-mark to the file Hspecification. Include no intervening white-space. The description is Bthen included as for any other item, as in the following example: 7

  *.TXT?   Search all TEXT files in this directory-  LAST_YEAR/*.TXT?   Search last year's files


NFor GUI browsers (such as Mosaic) this will produce an elegant text entry box Ninto which the search string can be entered, and an [execute] button Kthat may be clicked on (or moved to and activated for text-mode browsers). 

EThe following example illustrates a search item (that is also a live Cdemonstration) that would be created using the following construct:4

 HFRD_PRIMER_*.HTML?  Search this document for:
"
Search this document for:%


Search Options




HAdditional characters may be appended after the question-mark providing #additional control over the search.



Note:

0These may all be selectively applied to a singleHsearch by appending the required character(s) to the file specification.

OThe following example provides a live example, that would be created using the following construct: 7

 HFRD_PRIMER_*.HTML?AOC  Search this document for:
"
Search this document for:%
Case Sensitive:4 no3 yes
Output By:8 line= document;
About this search.
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4.2 - Directory Listings in Menus




IA menu can be used to provide a directory listing. The server returns a Ddirectory listing whenever a wildcard is present in a specification..

  *.*  The directory this document is in!


/The following provides an online demonstration:

!

4.3 - Full URLs in Menus




IIn place of a file specification a full URL can be supplied. It must be Oenclosed by quotation marks. This allows an item within a menu to specify any Ilink acceptable within the Hypertext environment. For example, the HFRD 5Hypertext Teledex could be included in a menu using: 6

  "http://host/teledex"  HFRD/DSTOS Hyper-Teledex


/The following provides an online demonstration:






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