One often encounters this form of textual link when a phrase like "See Chapter 2, section 1" appears in the text. This type of link is good but can be carried further. Imagine that each paragraph in a document had a label that described the topic discussed in the paragraph. Now one could encounter the phrase "See the section <correct use of the passive voice>" which would take you directly to the paragraph on passive voice. However, where is that paragraph? What Chapter? What Page?
When the document is online and being accessed via a HyperText processor, one simply points the mouse at the phrase <correct use of the passive voice> and asks to see that paragraph. Whether it is in chapter 10 or 2 is of no concern to the reader, the HyperText processor will find it and present it to the reader.
HyperText documents do not have to be read linearly like a book. One can begin in the section with the most interest and follow the links around the document to explore the subject. The creator of the HyperText document had only to attach descriptive labels to the various sections of the document.
If the idea of an outline is extended to an arrangement of ideas in subordinate relationships it becomes Hierarchical Text. Ideas are paragraphs or groups of paragraphs and a paragraph on precipitation might have subordinate paragraphs on the different kinds of precipitation that one might expect to find.
A textual statement that begins with "(" is labeled, and the labels are strings of non-punctuation characters separated by commas (",") between the first "(" and the closing ")" at the beginning of the statement. A link in the text consists of the non-punctuation characters between "<" and ">" characters anywhere in the text. When a label is a single word (or phrase with no embedded blanks), the link to it can be expressed without the "<" and ">" characters. Thus, each word in a Thinker document is a potential HyperText link to a statement somewhere in the hierarchy of statements that make up the document. Picture statements may not be labeled. In addition links can be delimited by changes in styles or by temporarily selected text.
To expand the flexibility of Thinker, a link may contain the name of a Thinker document other than the one in which the link is found. The document name is separated from the label by a comma. Thus, <Thinker:example,link> is a link to the section labeled "link" in the Thinker document called "example" on the disk named "Thinker".
Display parameters control the format of the document on the screen. Thinker can be instructed to display only the first line of each statement and give the appearance of a simple outline. By controlling the depth of the outline visible, the user can actually "see" very large portions of the document at one time. When the document is manipulated while viewing it in collapsed outline form, all of the text and pictures that are part of the document are moved when the visible portions are moved.
Text on the screen is modified as in many word processors. The cursor is positioned in front of text that is to be modified and typing is always in "insert" mode. Text is "selected" by sweeping the cursor over a block of text while holding the mouse button down. Selected text can be "cut" from the statement and "pasted" elsewhere or simply replaced by typing. Thinker has "search" and "replace" functions to complete the editing capabilities. Text may appear in many styles and type faces.
Thinker appears deceptively simple by design. The fact that labels and links are merely parts of the text eliminates much of the complexity associated with large numbers of obscure commands. However, one should not be fooled by the appearance of simplicity. The combination of Hierarchical text, Hypertext, and Word Processing functions makes Thinker a powerful Idea processor. Take the time to learn Thinker by working with the tutorial document (EXAMPLE) found on the Thinker distribution disk.
Thinker will display color PICT files (and color PICTs can be pasted into documents).