Macro: IF$HELP

  !A [~LASTIF] $41 |CI0   // If LASTIF is false jump to end of IF command.
  #XPUSH 1 !a     // Save line number of jump at static nesting level.
  #XPUSH 0 !n     // Save nesting level in stack 0.
  !1 !2 !3 !4 !5 !6 !7 !8 !9
  #XPOP 0 Q$      // Restore nesting level into Q.
  #XPOP  1 S$     // Restore IF JUMP line number
  #XPUSH !q !s        // Push it back for the ELSE.
  #IF (!n>!q)     // after a begin
    #FREF END$!r !s    // Make IF JUMP goto end of begin block.
  #ELSE       // same or lower nesting level
    #FREF (!a+1) !s    // Make IF JUMP goto end of the IF.
  #ENDIF