Add simple parser

Just getting warmed up. This will be used for note parsing.

src/lib.rs

@@ -2,6 +2,7 @@ mod app;
 //mod camera;
 mod contacts;
 mod error;
+mod parser;
 
 pub use app::Damus;
 pub use error::Error;

src/parser.rs

@@ -0,0 +1,41 @@
+use log::info;
+
+struct Parser<'a> {
+    data: &'a str,
+    pos: usize,
+}
+
+impl<'a> Parser<'a> {
+    fn new(data: &'a str) -> Parser {
+        Parser { data: data, pos: 0 }
+    }
+
+    fn parse_until(&mut self, needle: char) -> bool {
+        let mut count = 0;
+        for c in self.data[self.pos..].chars() {
+            if c == needle {
+                self.pos += count - 1;
+                return true;
+            } else {
+                count += 1;
+            }
+        }
+
+        return false;
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_parser() {
+        let s = "hey there #hashtag";
+        let mut parser = Parser::new(s);
+        parser.parse_until('#');
+        assert_eq!(parser.pos, 9);
+        parser.parse_until('t');
+        assert_eq!(parser.pos, 14);
+    }
+}