The text is then passed to the Interpreter to be tokenized and stored in the program. The edited line replaces the old version of that line in memory. An additional copy of any line of text can be created simply by changing the line-number and pressing <RETURN>.
If you use keyword abbreviations which cause a program line to exceed 80 characters, the excess characters will be lost when that line is edited, because the EDITOR will read only two physical screen lines. This is also why using INPUT for more than a total of 80 characters is not possible. Thus, for all practical purposes, the length of a line of BASIC text is limited to 80 characters as displayed on the screen.
Under certain conditions the SCREEN EDITOR treats the cursor control keys differently from their normal mode of handling. If the CuRSoR is positioned to the right of an odd number of double-quote marks (") the EDITOR operates in what is known as the QUOTE-MODE.
In quote mode data characters are entered normally but the cursor controls no longer move the CuRSoR, instead reversed characters are displayed which actually stand for the cursor control being entered. The same is true of the color control keys. This allows you to include cursor and color controls inside string data items in programs. You will find that this is a very important and powerful feature. That's because when the text inside the quotes is printed to the screen it performs the cursor positioning and color control functions automatically as part of the string. An example of using cursor controls in strings is:
You type --> 10 PRINT"A(R)(R)B(L)(L)(L)C(R)(R)D": REM(R)=CRSR RIGHT, (L)=CRSR LEFT Computer prints --> AC BD
The <DEL> key is the only cursor control NOT affected by quote mode. Therefore, if an error is made while keying in quote mode, the <CRSR LEFT> key can't be used to back up and strike over the error - even the <INST> key produces a reverse video character. Instead, finish entering the line, and then, after hitting the <RETURN> key, you can edit the line normally. Another alternative, if no further cursor-controls are needed in the string, is to press the <RUN/STOP> and <RESTORE> keys which will cancel QUOTE MODE. The cursor control keys that you can use in strings are shown in Table 2-2.
|This page has been created by Sami Rautiainen.|
|Read the small print.||Last updated November 15, 1998.|