Add associative map constraints and range refinement

crates/decodal-wasm/src/host_value.rs

@@ -84,6 +84,16 @@ fn object(fields: &Map<String, Value>) -> Result<HostValue, String> {
                 default,
             })
         }
+        "Map" => {
+            let value = fields
+                .get("value")
+                .ok_or_else(|| String::from("Map descriptor requires `value`"))?;
+            Ok(HostValue::MapConstraint {
+                value: Box::new(from_json(value)?),
+                constraints,
+                default,
+            })
+        }
         "Abstract" => Ok(HostValue::Abstract {
             constraints,
             default,
@@ -217,6 +227,23 @@ mod tests {
         );
     }
 
+    #[test]
+    fn converts_map_schema_descriptors() {
+        let value = serde_json::json!({
+            "$decodal": "Map",
+            "value": { "$decodal": "Bool" },
+            "default": {},
+        });
+        assert_eq!(
+            from_json(&value).unwrap(),
+            HostValue::MapConstraint {
+                value: Box::new(HostValue::bool_type()),
+                constraints: Vec::new(),
+                default: Some(Box::new(HostValue::object([] as [(&str, HostValue); 0]))),
+            }
+        );
+    }
+
     #[test]
     fn rejects_null_values() {
         assert!(