Thank you for the pointer to the erlang documentation. That looks like the syntax, with the : (erlang) vs. :: (elixir) difference.
Looking at that documentation inspired me to ask what elixir would construct, given the same layout as in the pattern, so I entered the following into iex. It seems that the affected bits are the least significant bits of the first byte and the most significant bits of the second byte.
Without a specification of how to place a 1 bit field and a 15-bit little endian field into two bytes, I can’t say I know how to write the elixir pattern,
I’m going to consider this as closed. (Not sure how to/if I can close a topic in this forum.) Thank you for your insights.
iex(57)> Enum.map(-16..16, &(<<0::1, &1::15-signed-little>> <> <<0>> <> <<&1::8>>))
[
<<120, 127, 0, 240>>,
<<120, 255, 0, 241>>,
<<121, 127, 0, 242>>,
<<121, 255, 0, 243>>,
<<122, 127, 0, 244>>,
<<122, 255, 0, 245>>,
<<123, 127, 0, 246>>,
<<123, 255, 0, 247>>,
<<124, 127, 0, 248>>,
<<124, 255, 0, 249>>,
<<125, 127, 0, 250>>,
<<125, 255, 0, 251>>,
<<126, 127, 0, 252>>,
<<126, 255, 0, 253>>,
<<127, 127, 0, 254>>,
<<127, 255, 0, 255>>,
<<0, 0, 0, 0>>,
<<0, 128, 0, 1>>,
<<1, 0, 0, 2>>,
<<1, 128, 0, 3>>,
<<2, 0, 0, 4>>,
<<2, 128, 0, 5>>,
<<3, 0, 0, 6>>,
<<3, 128, 0, 7>>,
<<4, 0, 0, 8>>,
<<4, 128, 0, 9>>,
<<5, 0, 0, 10>>,
<<5, 128, 0, 11>>,
<<6, 0, 0, 12>>,
<<6, 128, 0, 13>>,
<<7, 0, 0, 14>>,
<<7, 128, 0, 15>>,
<<8, 0, 0, 16>>
]
