Macro macro_state::append_state

append_state!() { /* proc-macro */ }

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!.

If no state file for the specified key exists, it will be created automatically. In this way, append_state! functions similar to how init_state! functions, especially in the no-existing-file case.

Note that if read_state! is called on an append_state!-based state file, newlines will be returned in the response.

Example

append_state!("my_key", "apples");
append_state!("my_key", "pears");
append_state!("my_key", "oh my!");
assert_eq!(read_state!("my_key"), "apples\npears\noh my!\n");