INIT
WANTSCREEN 

!Selective erase
RESET
PUSH "A\e[1\"qB\e[\"qC"
  ?screen_row 0 = "ABC"
PUSH "\e[G\e[?J"
  ?screen_row 0 = " B"

!Non-selective erase
RESET
PUSH "A\e[1\"qB\e[\"qC"
  ?screen_row 0 = "ABC"
PUSH "\e[G\e[J"
  ?screen_row 0 = ""