Once a form has been posted (displayed), you should funnel input
events to it through form_driver(3). This routine has two major
input cases; either the input is a form navigation request or it's
a printable ASCII character. The form driver requests are as
Move to the next page.
Move to the previous page.
Move to the first page.
Move to the last field.
Move to the next field.
Move to the previous field.
Move to the first field.
Move to the last field.
Move to the sorted next field.
Move to the sorted previous field.
Move to the sorted first field.
Move to the sorted last field.
Move left to a field.
Move right to a field.
Move up to a field.
Move down to a field.
Move to the next char.
Move to the previous char.
Move to the next line.
Move to the previous line.
Move to the next word.
Move to the previous word.
Move to the beginning of the field.
Move to the end of the field.
Move to the beginning of the line.
Move to the end of the line.
Move left in the field.
Move right in the field.
Move up in the field.
Move down in the field.
Insert or overlay a new line.
Insert a blank at the cursor.
Insert a blank line at the cursor.
Delete character at the cursor.
Delete character before the cursor.
Delete line at the cursor.
Delete blank-delimited word at the cursor.
Clear to end of line from cursor.
Clear to end of field from cursor.
Enter overlay mode.
Enter insert mode.
Scroll the field forward a line.
Scroll the field backward a line.
Scroll the field forward a page.
Scroll the field backward a page.
Scroll the field forward half a page.
Scroll the field backward half a page.
Scroll the field forward a character.
Scroll the field backward a character.
Horizontal scroll the field forward a line.
Horizontal scroll the field backward a line.
Horizontal scroll the field forward half a line.
Horizontal scroll the field backward half a line.
Display previous field choice.
Display next field choice.
If the second argument is a printable ASCII character, the
driver places it in the current position in the current field. If
it is one of the forms requests listed above, that request is
If the second argument is neither printable ASCII nor one of the
above pre-defined form requests, the driver assumes it is an
application-specific command and returns E_UNKNOWN_COMMAND.
Application-defined commands should be defined relative to
MAX_COMMAND, the maximum value of these pre-defined