Current variable.

When you start Erable (and each time you reset it by typing VER followed by the ENTER key), the current variable is set to 'X'. The DEL key is assigned to X. It is therefore easy to enter a symbolic expression depending of X because you do not need to press the $\alpha$ key. You may need to modify the current variable. This is done by changing the content of the VX variable (in the { HOME } directory). For example to set the current variable to Y, type:
Y 'VX' STO