Implement classification of token types

src/main.rs

@@ -3,16 +3,37 @@ extern crate ansi_term;
 use std::io::{BufRead, BufReader};
 use std::fs::File;
 use std::{env, process};
+use std::convert::From;
 
 
+#[derive(Debug, Eq, PartialEq)]
 enum LineType {
+    Empty,
     Title(String),
-    Empty(String),
     Description(String),
     ExampleText(String),
     ExampleCode(String),
+    Other(String),
 }
 
+impl<'a> From<&'a str> for LineType {
+    /// Convert a string slice to a LineType. Newlines and whitespace are trimmed.
+    fn from(line: &'a str) -> LineType {
+        let trimmed = line.trim();
+        let mut chars = trimmed.chars();
+        match chars.next() {
+            None => LineType::Empty,
+            Some('#') => LineType::Title(trimmed.trim_left_matches(|chr: char| chr == '#' || chr.is_whitespace()).into()),
+            Some('>') => LineType::Description(trimmed.trim_left_matches(|chr: char| chr == '>' || chr.is_whitespace()).into()),
+            Some('-') => LineType::ExampleText(trimmed.trim_left_matches(|chr: char| chr == '-' || chr.is_whitespace()).into()),
+            Some('`') if chars.last() == Some('`') => LineType::ExampleCode(trimmed.trim_matches(|chr: char| chr == '`' || chr.is_whitespace()).into()),
+            _ => LineType::Other(trimmed.into()),
+        }
+    }
+}
+
+
+#[derive(Debug)]
 struct Tokenizer<R: BufRead> {
     reader: R,
     current_line: String,
@@ -27,12 +48,12 @@ impl<R> Tokenizer<R> where R: BufRead {
         }
     }
 
-    fn next(&mut self) -> Option<&str> {
+    fn next(&mut self) -> Option<LineType> {
         self.current_line.clear();
         let bytes_read = self.reader.read_line(&mut self.current_line).unwrap();
         match bytes_read {
             0 => None,
-            _ => Some(&self.current_line),
+            _ => Some(LineType::from(&self.current_line[..])),
         }
     }
 
@@ -68,7 +89,25 @@ fn main() {
 
     // Tokenize and print output
     while let Some(token) = tokenizer.next() {
-        print!("{}", token);
+        println!("{:?}", token);
     }
 
 }
+
+
+#[cfg(test)]
+mod test {
+    use super::LineType;
+
+    #[test]
+    fn test_linetype_from_str() {
+        assert_eq!(LineType::from(""), LineType::Empty);
+        assert_eq!(LineType::from(" \n \r"), LineType::Empty);
+        assert_eq!(LineType::from("# Hello there"), LineType::Title("Hello there".into()));
+        assert_eq!(LineType::from("> tis a description \n"), LineType::Description("tis a description".into()));
+        assert_eq!(LineType::from("- some command"), LineType::ExampleText("some command".into()));
+        assert_eq!(LineType::from("`$ cargo run`"), LineType::ExampleCode("$ cargo run".into()));
+        assert_eq!(LineType::from("`$ cargo run"), LineType::Other("`$ cargo run".into()));
+        assert_eq!(LineType::from("asdf"), LineType::Other("asdf".into()));
+    }
+}