feat(examples): add iter example

examples/custom.rs

@@ -0,0 +1,71 @@
+use std::convert::From;
+use std::env::args;
+use std::fs;
+use std::io::{Error as IOError, Write};
+use std::result::Result;
+use std::string::FromUtf8Error;
+
+use orgize::export::*;
+use orgize::{Container, Org};
+use slugify::slugify;
+
+#[derive(Debug)]
+enum MyError {
+    IO(IOError),
+    Heading,
+    Utf8(FromUtf8Error),
+}
+
+// From<std::io::Error> trait is required for custom error type
+impl From<IOError> for MyError {
+    fn from(err: IOError) -> Self {
+        MyError::IO(err)
+    }
+}
+
+impl From<FromUtf8Error> for MyError {
+    fn from(err: FromUtf8Error) -> Self {
+        MyError::Utf8(err)
+    }
+}
+
+struct MyHtmlHandler;
+
+impl HtmlHandler<MyError> for MyHtmlHandler {
+    fn start<W: Write>(&mut self, mut w: W, container: Container<'_>) -> Result<(), MyError> {
+        let mut default_handler = DefaultHtmlHandler;
+        match container {
+            Container::Headline(hdl) => {
+                if hdl.level > 6 {
+                    return Err(MyError::Heading);
+                } else {
+                    let slugify = slugify!(hdl.title);
+                    write!(
+                        w,
+                        "<h{0}><a id=\"{1}\" href=\"#{1}\">{2}</a></h{0}>",
+                        hdl.level, slugify, hdl.title,
+                    )?;
+                }
+            }
+            _ => default_handler.start(w, container)?,
+        }
+        Ok(())
+    }
+}
+
+fn main() -> Result<(), MyError> {
+    let args: Vec<_> = args().collect();
+
+    if args.len() < 2 {
+        eprintln!("Usage: {} <org-file>", args[0]);
+    } else {
+        let contents = String::from_utf8(fs::read(&args[1])?)?;
+
+        let mut writer = Vec::new();
+        Org::parse(&contents).html(&mut writer, MyHtmlHandler)?;
+
+        println!("{}", String::from_utf8(writer)?);
+    }
+
+    Ok(())
+}