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#[derive(Debug)] // <1> Enable this enum to be printed to the screen via auto-generated code
enum Event {
Update, // <2> Create three variants of Event, including one value for unrecognized events
Delete, // <2>
Unknown, // <2>
}
type Message = String; // <3> A convenient name for String for use in this crate's context
fn parse_log(line: &'static str) -> (Event, Message) { // <4> A function for parsing a line and converting it into semi-structured data
let parts: Vec<&str> = line.splitn(2, ' ').collect(); // <5> `collect()` consumes an iterator (returned from `line.splitn()`) and returns `Vec<T>`
if parts.len() == 1 { // <6> If `line.splitn()` didn't split `log` into two parts, return an error
return (Event::Unknown, String::from(line))
}
let event = parts[0]; // <7> Assign each part to a variable for ease of future use
let rest = String::from(parts[1]); // <7>
match event {
"UPDATE" | "update" => (Event::Update, rest), // <8> When we match a known event, return structured data
"DELETE" | "delete" => (Event::Delete, rest), // <8>
_ => (Event::Unknown, String::from(line)), // <9> If we don't recognize the event type, return the whole line
}
}
fn main() {
let log = "BEGIN Transaction XK342
UPDATE 234:LS/32231 {\"price\": 31.00} -> {\"price\": 40.00}
DELETE 342:LO/22111";
for line in log.lines(){
let parse_result = parse_log(line);
println!("{:?}", parse_result);
}
}
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