This allows you to change the material that is displayed - primarily in the table of contents (TOC). It's being extended to other windows such as 'Expand Subtree' but there is only a global control at present.
Note that costwish was originally developed for NON-TEXTUAL data, so display of large conventional manuscripts (e.g. books and plays) has not been customised and may appear creaky. However, it can be easily customised for any DTD (see the PLAY example). The use of PEL and CDATA is still experimental since SGML does not manage record-ends (REs) very happily.
TOC is the primary window and resource for costwish. The SGML document is interpreted as a tree-like table of contents, based solely on the level of hierarchy in the ESIS tree. This works well for documents structured in this way (e.g. Frontmatter, Body (Chapter1, Chapter2), BackMatter), where the tags contain content. If the tags are used as formatting switches (e.g. <B>bold text </B>) a hierarchical display isn't appropriate. However, costwish has no way of knowing this when the document is read in!
The TOC is an active area but is not writable (costwish is NOT an editor). In general not all of the nodes are displayed - this depends on the setting of the View controls and the Hide menus. The nodes are shown by a text string which is determined by a simple (user-modifiable) algorithm. By default it shows the GI ("tag"), but can be tweaked to show an attribute value or some of the content so that it is more informative. Additionally the GI, the address, the content, and more can be shown
Each node can be clicked on the text (Button-1) and will attempt to display the node and its contents. The results will be shown in a separate window (see Node Action.) (PEL and CDATA nodes may not display - I continue to tweak this sort of thing.)
The user can expand or contract the table of contents. This is still under development! "+-" after the text string indicates that the node has child subnodes which can be revelaed/hidden. Expand (+) reveals all the children of the node (any existing grandchildren will be contracted). Contract (-) hides all descendants of the node. The content of a node (first few characters only) will be displayed if "View | Show Text Content" is set. To display the content in greater detail (or to process it into HTML) requires either displaying in a subnode window or being part of an Event Stream (see Node Action).
NOTE: The options in this menu may be repackaged - perhaps in a separate 'Settings' window (expansion of 'Display Settings').
NOTE: Certain node types may have display conditions set elsewhere (such as "Hide Children" and "Hide Node". These override the regulation by depth, and will need to be unset if certain children are to be automatically displayed
NOTE: Manual activation of expand/contract (+-) overrides the depth regulation.
NOTE: "Redisplay" uses only the depth and Hide mechanisms. Any subtrees that were created by other means (e.g. expand/contract or Search) will be lost from the display.
This gives the maximum number of levels in a Node window. The node itself is level 1 (e.g. if node "Chapter 1" in the TOC is selected, this should appear at the top of the tree). The default is 4 at present.
NOTE: "Hide Children" and "Hide Node" also apply to this and take precedence over the depth
After setting one of these you may need to Redisplay the contents.
Peter Murray-Rust
April 1996