This is achieved by storing the resources we need to acquire for
interacting with the flipdot (socket fd and addrinfo struct) in a
`struct flipdot` that is dynamically allocated and treated as an opaque
pointer object via the BQN FFI.
To make sure these resources are released correctly, we only provide a
lisp style WithFlipdot to the user which takes care of acquiring and
releasing the `struct flipdot`. This works even if an error occurs in
the function the user provides thanks to _defer_. I'm not sure if
calling it _defer_ is right since Go's error handling works differently,
so defer really is deferred execution in a sense which doesn't really
fit what we're doing here. The closest is probably Haskell's bracket,
but that name references it's triadic nature which doesn't fit our
implementation.
Change-Id: Iff65d277a448dbe0c6ac93e816ece5ab6fa10190
Reviewed-on: https://cl.tvl.fyi/c/depot/+/13011
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
The idea of this “library” is to do the least. The most natural way to
represent the image to render on a flipdot image is a two dimensional
array of booleans. This something BQN is very well equipped for, i.e. it
has primitives that are designed to deal with this type of data
structure. The only thing we have to do is to take care of sending such
arrays to the flipdot display via the μCCC's un(der)documented UDP
protocol.
Compact implements the conversion from a boolean array to a bitmap that
only uses 1 bit per pixel. All socket code is written in C and invoked
via •FFI. Currently, every time a bitmap is sent to a display, the
target host has to be resolved again. This should be fixed in the
future.
Change-Id: Idea7c81baac919da93c88a69f98cbbbd026fa328
Reviewed-on: https://cl.tvl.fyi/c/depot/+/13010
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
