Fail on line containing no instruction but only a comment. ( starting with ; )

[dglaude]

; just comment produce "IndexError: list index out of range"

shade = """
.program shade
  ; just a comment
    set pins 1 [1]  ; Drive pin high and then delay for [x] cycle
    set pins 0 [31] ; Drive pin low and then delay for [x] cycle
"""