Started Rust in Action MEAP.

1 files changed, 35 insertions, 0 deletions

diff --git a/meap/meap-code/ch3/ch3-parse-log.rs b/meap/meap-code/ch3/ch3-parse-log.rs
new file mode 100644
index 0000000..b675aa1
--- /dev/null
+++ b/meap/meap-code/ch3/ch3-parse-log.rs
@@ -0,0 +1,35 @@
+#[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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