1 files changed, 93 insertions, 0 deletions
diff --git a/src/file/format/yaml.rs b/src/file/format/yaml.rs
new file mode 100644
index 0000000..2840438
--- /dev/null
+++ b/src/file/format/yaml.rs
@@ -0,0 +1,93 @@
+use yaml_rust as yaml;
+use source::Source;
+use std::error::Error;
+use std::fmt;
+use std::collections::{BTreeMap, HashMap};
+use std::mem;
+use value::{Value, ValueKind};
+
+pub fn parse(uri: Option<&String>, text: &str, namespace: Option<&String>) -> Result<HashMap<String, Value>, Box<Error>> {
+    let mut docs = yaml::YamlLoader::load_from_str(text)?;
+
+    // Designate root
+    let mut root = match docs.len() {
+        0 => yaml::Yaml::Hash(BTreeMap::new()),
+        1 => mem::replace(&mut docs[0], yaml::Yaml::Null),
+        n => {
+            return Err(Box::new(MultipleDocumentsError(n)));
+        }
+    };
+
+    // Limit to namespace
+    if let Some(namespace) = namespace {
+        root = yaml::Yaml::Hash(match root {
+            yaml::Yaml::Hash(ref mut table) => {
+                if let Some(yaml::Yaml::Hash(table)) = table.remove(&yaml::Yaml::String(namespace.clone())) {
+                    table
+                } else {
+                    BTreeMap::new()
+                }
+            }
+
+            _ => {
+                BTreeMap::new()
+            }
+        });
+    };
+
+    // TODO: Have a proper error fire if the root of a file is ever not a Table
+    let value = from_yaml_value(uri, &root);
+    match value.kind {
+        ValueKind::Table(map) => Ok(map),
+
+        _ => Ok(HashMap::new()),
+    }
+}
+
+fn from_yaml_value(uri: Option<&String>, value: &yaml::Yaml) -> Value {
+    match *value {
+        yaml::Yaml::String(ref value) => Value::new(uri, ValueKind::String(value.clone())),
+        yaml::Yaml::Real(ref value) => Value::new(uri, ValueKind::Float(value.parse::<f64>().unwrap())),
+        yaml::Yaml::Integer(value) => Value::new(uri, ValueKind::Integer(value)),
+        yaml::Yaml::Boolean(value) => Value::new(uri, ValueKind::Boolean(value)),
+        yaml::Yaml::Hash(ref table) => {
+            let mut m = HashMap::new();
+            for (key, value) in table {
+                if let Some(k) = key.as_str() {
+                    m.insert(k.to_owned(), from_yaml_value(uri, value));
+                }
+                // TODO: should we do anything for non-string keys?
+            }
+            Value::new(uri, ValueKind::Table(m))
+        }
+        yaml::Yaml::Array(ref array) => {
+            let mut l = Vec::new();
+
+            for value in array {
+                l.push(from_yaml_value(uri, value));
+            }
+
+            Value::new(uri, ValueKind::Array(l))
+        }
+        // TODO: how should we handle Null and BadValue?
+        _ => {
+            unimplemented!();
+        }
+
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+struct MultipleDocumentsError(usize);
+
+impl fmt::Display for MultipleDocumentsError {
+    fn fmt(&self, format: &mut fmt::Formatter) -> fmt::Result {
+        write!(format, "Got {} YAML documents, expected 1", self.0)
+    }
+}
+
+impl Error for MultipleDocumentsError {
+    fn description(&self) -> &str {
+        "More than one YAML document provided"
+    }
+}