80-Bus News


May–June 1984, Volume 3, Issue 3

Page 6 of 51

It is best to consider that ALL operations will occur at the place pointed to by the arrow. e.g. BS will delete the letter pointed to and characters under/​after the cursor will move left/up. Any typed Characters will be inserted in the ‘gap’ pointed to, and text under/​after the cursor will move right/​down. This is different to editing in BASIC etc. where characters will ‘overtype’ unless space is created by shift/​right arrow. The Insert mode is terminated by a ^Z.

A number of commands (also used in Insert mode) are available to move the cursor forwards or backwards through the text by units of one character/​word/​line/​paragraph/​Quarter page. The main cursor commands are Right and Left arrow, to move one character, Shift Right or Shift Left arrow to move one Word, Up or Down arrow to move one (logical) line, Shift Up or Shift Down arrow to move one Paragraph. In command mode, text can also be scanned in ‘Pages’. The length of a page can be changed from the default value by using the ‘3’ & ‘4’ commands, to suit screen or Printer output. Page markers can then be inserted into the text, or removed at will, by simple commands. If Pages are marked forward and backward scanning is supported (8 or 9 commands). Any page may be printed (P command) and if the cursor is not moved, repeated printing of a Page is possible. More sophisticated printing is allowed under the Spool overlay.

It is important to realize that a line MAY NOT mean one line as seen on the screen. One normally enters text into a file by just typing words, spaces and punctuation, but WITHOUT pressing ENTER at the end of each screen line. The text will ‘wrap around’ onto the next line of the screen, etc., although some words may appear broken when the end of screen line is reached. In memory though, the text will be continuous. Thus a paragraph of say 200 words may be entered, and the cursor may be half way down the screen but the line counter will still say line 1, because the logical end of line is marked by a CR,​LF sequence, which results from pressing ENTER, or from formatting. Half a dozen such paragraphs may occupy several K. of memory and take two or three screens to display fully, but may only register six lines on the status display.

When the text is formatted to the desired length however, the program will place a CR,​LF at the end of every line of 76 (or whatever length set – N.B. These are .1″ steps, NOT characters), and the line counter will display the correct count. Since the screen can only display 48 or 80 chars. on a line, any lines formatted longer than this will ‘wrap around’, and this will result in the line count indicator not agreeing with lines as counted on the screen.

Another consequence of the lack of CR,​LF before formatting is that the UP/DOWN arrow keys will cause the cursor to jump the whole length of the logical line. This makes reaching the middle of a paragraph by cursor character or word commands tedious. The answer is to format frequently, or to press ENTER or RETURN fairly often when near the Right hand side of the screen. Formatting takes longer as the ammount of text grows, and it is not necessary to put the cursor to the start of the text each time a format is done. It can be placed at the end of the previous formatted part. If formatting is done on the last one or two paragraphs entered, it is very quick. The whole text only need be reformatted if changes are made near the start, or some other change is needed such as a different line length.

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