Like write_state!, but instead appends the specified value (newline-delimited) to the
state file. Newlines contained in the value are automatically escaped so you can think of
this as appending to a Vec<String> for all intents and purposes. Calling append_state!
is also more efficient than re-writing an entire state file via write_state! since the
low level append IO option is not used by write_state!.
Returns the value for the specified key, if it exists. If it does not exist, the key is
created and set to the specified default_value, and then the default_value is returned.
Reads the state value for the specified key. Since macro_state functions as a
compile-time key-value store, read_state! attempts to read the state value associaed
with the specified key.
Reads the state value for the specified key and parses it as a Vec<String> where each new
line is treated as a separate element in the Vec. Should be used in conjunction with
append_state! to read and write lists of values from macro state storage.
Writes the specified value as the state for the specified state key. macro_state
itself functions as a compile-time key-value store, and this is how you write a value to a
specific key.