1 files changed, 55 insertions, 0 deletions
diff --git a/src/file/format/dhall.rs b/src/file/format/dhall.rs
new file mode 100644
index 0000000..03bee38
--- /dev/null
+++ b/src/file/format/dhall.rs
@@ -0,0 +1,55 @@
+use std::collections::HashMap;
+use std::error::Error;
+
+use crate::{
+    error::Unexpected,
+    value::{Value, ValueKind},
+    ConfigError,
+};
+
+pub fn parse(
+    uri: Option<&String>,
+    text: &str,
+) -> Result<HashMap<String, Value>, Box<dyn Error + Send + Sync>> {
+    let value = from_dhall_value(uri, serde_dhall::from_str(text).parse()?);
+    match value.kind {
+        ValueKind::Table(map) => Ok(map),
+        ValueKind::Nil => Err(Unexpected::Unit),
+        ValueKind::Boolean(value) => Err(Unexpected::Bool(value)),
+        ValueKind::Integer(value) => Err(Unexpected::Integer(value)),
+        ValueKind::Float(value) => Err(Unexpected::Float(value)),
+        ValueKind::String(value) => Err(Unexpected::Str(value)),
+        ValueKind::Array(value) => Err(Unexpected::Seq),
+    }
+    .map_err(|err| ConfigError::invalid_root(uri, err))
+    .map_err(|err| Box::new(err) as Box<dyn Error + Send + Sync>)
+}
+
+fn from_dhall_value(uri: Option<&String>, value: serde_dhall::SimpleValue) -> Value {
+    match value {
+        serde_dhall::SimpleValue::Num(num) => match num {
+            serde_dhall::NumKind::Bool(b) => Value::new(uri, ValueKind::Boolean(b)),
+            serde_dhall::NumKind::Natural(n) => Value::new(uri, ValueKind::Integer(n as i64)),
+            serde_dhall::NumKind::Integer(i) => Value::new(uri, ValueKind::Integer(i)),
+            serde_dhall::NumKind::Double(d) => Value::new(uri, ValueKind::Float(f64::from(d))),
+        },
+        serde_dhall::SimpleValue::Text(string) => Value::new(uri, ValueKind::String(string)),
+        serde_dhall::SimpleValue::List(list) => Value::new(
+            uri,
+            ValueKind::Array(list.into_iter().map(|v| from_dhall_value(uri, v)).collect()),
+        ),
+        serde_dhall::SimpleValue::Record(rec) => Value::new(
+            uri,
+            ValueKind::Table(
+                rec.into_iter()
+                    .map(|(k, v)| (k, from_dhall_value(uri, v)))
+                    .collect(),
+            ),
+        ),
+        serde_dhall::SimpleValue::Optional(Some(value))
+        | serde_dhall::SimpleValue::Union(_, Some(value)) => from_dhall_value(uri, *value),
+        serde_dhall::SimpleValue::Optional(None) | serde_dhall::SimpleValue::Union(_, None) => {
+            Value::new(uri, ValueKind::Nil)
+        }
+    }
+}