Causes the terminal driver to transmit the text of the current line,
from the start of the line through the end of the line, to the PRO/5 program
(in the input buffer). The transmission is terminated with an ASCII CR
(carriage return). If the terminal is in graphics mode (as set by the
'GS' mnemonic) four
bytes are transmitted for each character: the 'RGB' value (2 bytes), followed
by the 'ATTR' value (1 byte), followed by the character itself (1 byte).
The 'RGB' and 'ATTR' values will set the high-order bit in each byte.
Note: If you are doing 'RL' in 'GS' mode, use READRECORD, not INPUT.
These characters will have the most significant bit set to help distinguish them from text data. Otherwise, the format is the same as specified in the FIN() data for a terminal.
This statement reads a line off the screen at the current cursor position and stores it in SCREEN_LINE$
This statement reads the 10th line off the screen and puts its contents into SCREEN_LINE$.