Comments

Comments start anywhere outside a string or character literal with the hash character #. Comments consist of a concatenation of comment pieces. A comment piece starts with # and runs until the end of the line. The end of line characters belong to the piece. If the next line only consists of a comment piece with no other tokens between it and the preceding one, it does not start a new comment:

i = 0     # This is a single comment over multiple lines.
  # The scanner merges these two pieces.
  # The comment continues here.

Documentation comments are comments that start with two ##. Documentation comments are tokens; they are only allowed at certain places in the input file as they belong to the syntax tree!