Handle RBSHash types

Add support for RBS hashes (rbs_hash_t), which are used in Record types
and Function keyword arguments

Author: alexcrocha

rust/ruby-rbs/build.rs

@@ -172,6 +172,15 @@ fn generate(config: &Config) -> Result<(), Box<dyn Error>> {
                         )?;
                         writeln!(file, "    }}")?;
                     }
+                    "rbs_hash" => {
+                        writeln!(file, "    pub fn {}(&self) -> RBSHash {{", field.name)?;
+                        writeln!(
+                            file,
+                            "        RBSHash::new(self.parser, unsafe {{ (*self.pointer).{} }})",
+                            field.c_name()
+                        )?;
+                        writeln!(file, "    }}")?;
+                    }
                     "rbs_location" => {
                         writeln!(file, "    pub fn {}(&self) -> RBSLocation {{", field.name)?;
                         writeln!(

rust/ruby-rbs/src/lib.rs

@@ -91,6 +91,47 @@ impl NodeList {
     }
 }
 
+pub struct RBSHash {
+    parser: *mut rbs_parser_t,
+    pointer: *mut rbs_hash,
+}
+
+impl RBSHash {
+    pub fn new(parser: *mut rbs_parser_t, pointer: *mut rbs_hash) -> Self {
+        Self { parser, pointer }
+    }
+
+    /// Returns an iterator over the key-value pairs.
+    #[must_use]
+    pub fn iter(&self) -> RBSHashIter {
+        RBSHashIter {
+            parser: self.parser,
+            current: unsafe { (*self.pointer).head },
+        }
+    }
+}
+
+pub struct RBSHashIter {
+    parser: *mut rbs_parser_t,
+    current: *mut rbs_hash_node_t,
+}
+
+impl Iterator for RBSHashIter {
+    type Item = (Node, Node);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.current.is_null() {
+            None
+        } else {
+            let pointer_data = unsafe { *self.current };
+            let key = unsafe { Node::new(self.parser, pointer_data.key) };
+            let value = unsafe { Node::new(self.parser, pointer_data.value) };
+            self.current = pointer_data.next;
+            Some((key, value))
+        }
+    }
+}
+
 pub struct RBSLocation {
     pointer: *const rbs_location_t,
     #[allow(dead_code)]
@@ -237,4 +278,52 @@ mod tests {
             panic!("No literal type node found");
         }
     }
+
+    #[test]
+    fn test_rbs_hash_via_record_type() {
+        // RecordType stores its fields in an RBSHash via all_fields()
+        let rbs_code = r#"type foo = { name: String, age: Integer }"#;
+        let signature = parse(rbs_code.as_bytes());
+        assert!(signature.is_ok(), "Failed to parse RBS signature");
+
+        let signature_node = signature.unwrap();
+        if let Node::TypeAlias(type_alias) = signature_node.declarations().iter().next().unwrap()
+            && let Node::RecordType(record) = type_alias.type_()
+        {
+            let hash = record.all_fields();
+            let fields: Vec<_> = hash.iter().collect();
+            assert_eq!(fields.len(), 2, "Expected 2 fields in record");
+
+            // Build a map of field names to type names
+            let mut field_types: Vec<(String, String)> = Vec::new();
+            for (key, value) in &fields {
+                let Node::Symbol(sym) = key else {
+                    panic!("Expected Symbol key");
+                };
+                let Node::RecordFieldType(field_type) = value else {
+                    panic!("Expected RecordFieldType value");
+                };
+                let Node::ClassInstanceType(class_type) = field_type.type_() else {
+                    panic!("Expected ClassInstanceType");
+                };
+
+                let key_name = String::from_utf8(sym.name().to_vec()).unwrap();
+                let type_name_node = class_type.name();
+                let type_name_sym = type_name_node.name();
+                let type_name = String::from_utf8(type_name_sym.name().to_vec()).unwrap();
+                field_types.push((key_name, type_name));
+            }
+
+            assert!(
+                field_types.contains(&("name".to_string(), "String".to_string())),
+                "Expected 'name: String'"
+            );
+            assert!(
+                field_types.contains(&("age".to_string(), "Integer".to_string())),
+                "Expected 'age: Integer'"
+            );
+        } else {
+            panic!("Expected TypeAlias with RecordType");
+        }
+    }
 }