Outliner

From Wikipedia, the free encyclopedia

An outliner is a special text editor that allows text to be structured as an outline. Outliners are typically used for computer programming, collecting or organizing ideas, Getting Things Done, or project management. It is generally acknowledged that Doug Engelbart was the first to see the advantages of the expandable-outline user interface paradigm in software.

1 Hierarchy - principle attribute
2 Intrinsic vs. extrinsic outliners
3 File formats
4 See also
5 External links

[edit] Hierarchy - principle attribute

The principle attribute of outline editors is that they support or enforce the use of a hierarchy in most of their functions (below), not just in the display of information. For example:

Editing: Sound parent-child relationships are enforced when the user modifies the document structure. For example:
- Promoting, demoting, copying, or deleting a parent has the same effect on the children.
- Every item entry must be within one level of its predecessor, such that each item must be a sibling or child of the preceding item (thus, no item can be a great-grandchild of the preceding item).
Viewing: The tool enables the user to affect the display by level. For example:
- Applying styles by outline level (e.g., bold all 1st level items)
- Displaying selected levels (e.g., show all 1st and 2nd level items, but none deeper).
Search: The tool retrieves all items that contain the query terms plus the ancestors (parent, grandparent...) that give them context.
File import / export: Both the content and structure of outlines are conveyed when files are imported or exported (e.g., from and to tab-indented files).

[edit] Intrinsic vs. extrinsic outliners

It is possible to distinguish between intrinsic and extrinsic outlines. An intrinsic (or classic) outline is one in which the text itself is organized in an outline format. Content elements are structural, and vice versa. An extrinsic outliner is a product that presents labels, titles, or headings hierarchically in one pane and related text in another pane. Content elements and structural elements are separated in this model. The principle benefits of intrinsic outliners are that editing is simple and thus quick because the user need not manage two panes, and that the user has great flexibility to mix concise headings and verbose text as needed. The principal benefit of extrinisic outliners is that they enforce concise structures (heading labels of few words) that simplify and thus accelerate navigation of the structure.