[clear] key

[compsystems]

Hello, the operation of the [clear] key in the simulator of the recent NumWorks calculator
http://www.numworks.com/simulator performs the following operation.

Case # 1: If the cursor is in the last position, delete all characters
123456 | [clear] clears the entry line

case # 2: If the cursor is not in the last position, delete the characters from the cursor to the end
123 | 456 [clear] returns 123

Please clone this last feature, which is too useful to remove portions of algebraic expressions.