1 files changed, 146 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index c724687..6b61dea 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,6 +11,12 @@ pub trait BuildFromRef {
     fn ref_to(query: impl Into<String>) -> Self;
 }
 
+fn get_id_from_ref(r#ref: &str) -> Option<&str> {
+    r#ref
+        .strip_prefix(r#"[id=""#)
+        .and_then(|r#ref| r#ref.strip_suffix(r#""]"#))
+}
+
 #[derive(Debug, PartialEq, Eq, Default)]
 #[cfg_attr(feature = "parse-knuffel", derive(Decode))]
 pub struct Schema {
@@ -18,6 +24,48 @@ pub struct Schema {
     pub document: Document,
 }
 
+impl Schema {
+    /// Panics if ref is not of the form `[id="foo"]`.
+    pub fn resolve_node_ref(&self, r#ref: &str) -> Option<&Node> {
+        let id = get_id_from_ref(r#ref).expect("invalid ref");
+        self.document
+            .nodes
+            .iter()
+            .filter_map(|node| node.find_node_by_id(id))
+            .next()
+    }
+
+    /// Panics if ref is not of the form `[id="foo"]`.
+    pub fn resolve_prop_ref(&self, r#ref: &str) -> Option<&Prop> {
+        let id = get_id_from_ref(r#ref).expect("invalid ref");
+        self.document
+            .nodes
+            .iter()
+            .filter_map(|node| node.find_prop_by_id(id))
+            .next()
+    }
+
+    /// Panics if ref is not of the form `[id="foo"]`.
+    pub fn resolve_value_ref(&self, r#ref: &str) -> Option<&Value> {
+        let id = get_id_from_ref(r#ref).expect("invalid ref");
+        self.document
+            .nodes
+            .iter()
+            .filter_map(|node| node.find_value_by_id(id))
+            .next()
+    }
+
+    /// Panics if ref is not of the form `[id="foo"]`.
+    pub fn resolve_children_ref(&self, r#ref: &str) -> Option<&Children> {
+        let id = get_id_from_ref(r#ref).expect("invalid ref");
+        self.document
+            .nodes
+            .iter()
+            .filter_map(|node| node.find_children_by_id(id))
+            .next()
+    }
+}
+
 #[cfg(feature = "parse-knuffel")]
 impl Schema {
     pub fn parse(
@@ -131,6 +179,50 @@ pub struct Node {
     pub children: Vec<Children>,
 }
 
+impl Node {
+    fn find_node_by_id(&self, id: &str) -> Option<&Node> {
+        if self.id.as_deref() == Some(id) {
+            Some(self)
+        } else {
+            self.children
+                .iter()
+                .filter_map(|children| children.find_node_by_id(id))
+                .next()
+        }
+    }
+
+    fn find_prop_by_id(&self, id: &str) -> Option<&Prop> {
+        self.props
+            .iter()
+            .filter_map(|prop| prop.find_prop_by_id(id))
+            .chain(
+                self.children
+                    .iter()
+                    .filter_map(|children| children.find_prop_by_id(id)),
+            )
+            .next()
+    }
+
+    fn find_value_by_id(&self, id: &str) -> Option<&Value> {
+        self.values
+            .iter()
+            .filter_map(|value| value.find_value_by_id(id))
+            .chain(
+                self.children
+                    .iter()
+                    .filter_map(|children| children.find_value_by_id(id)),
+            )
+            .next()
+    }
+
+    fn find_children_by_id(&self, id: &str) -> Option<&Children> {
+        self.children
+            .iter()
+            .filter_map(|children| children.find_children_by_id(id))
+            .next()
+    }
+}
+
 impl BuildFromRef for Node {
     fn ref_to(query: impl Into<String>) -> Self {
         Self {
@@ -157,6 +249,16 @@ pub struct Prop {
     pub validations: Vec<Validation>,
 }
 
+impl Prop {
+    fn find_prop_by_id(&self, id: &str) -> Option<&Prop> {
+        if self.id.as_deref() == Some(id) {
+            Some(self)
+        } else {
+            None
+        }
+    }
+}
+
 impl BuildFromRef for Prop {
     fn ref_to(query: impl Into<String>) -> Self {
         Self {
@@ -183,6 +285,16 @@ pub struct Value {
     pub validations: Vec<Validation>,
 }
 
+impl Value {
+    fn find_value_by_id(&self, id: &str) -> Option<&Value> {
+        if self.id.as_deref() == Some(id) {
+            Some(self)
+        } else {
+            None
+        }
+    }
+}
+
 impl BuildFromRef for Value {
     fn ref_to(query: impl Into<String>) -> Self {
         Self {
@@ -205,6 +317,40 @@ pub struct Children {
     pub nodes: Vec<Node>,
 }
 
+impl Children {
+    fn find_node_by_id(&self, id: &str) -> Option<&Node> {
+        self.nodes
+            .iter()
+            .filter_map(|node| node.find_node_by_id(id))
+            .next()
+    }
+
+    fn find_prop_by_id(&self, id: &str) -> Option<&Prop> {
+        self.nodes
+            .iter()
+            .filter_map(|node| node.find_prop_by_id(id))
+            .next()
+    }
+
+    fn find_value_by_id(&self, id: &str) -> Option<&Value> {
+        self.nodes
+            .iter()
+            .filter_map(|node| node.find_value_by_id(id))
+            .next()
+    }
+
+    fn find_children_by_id(&self, id: &str) -> Option<&Children> {
+        if self.id.as_deref() == Some(id) {
+            Some(self)
+        } else {
+            self.nodes
+                .iter()
+                .filter_map(|node| node.find_children_by_id(id))
+                .next()
+        }
+    }
+}
+
 impl BuildFromRef for Children {
     fn ref_to(query: impl Into<String>) -> Self {
         Self {