1 files changed, 32 insertions, 0 deletions
diff --git a/src/StackFrame.kt b/src/StackFrame.kt
new file mode 100644
index 0000000..66d74b2
--- /dev/null
+++ b/src/StackFrame.kt
@@ -0,0 +1,32 @@
+package moe.nea.lisp
+
+class StackFrame(val parent: StackFrame?) {
+
+    val variables = mutableMapOf<String, LispData>()
+
+    interface MetaKey<T>
+
+    private val meta: MutableMap<MetaKey<*>, Any> = mutableMapOf()
+
+    fun <T : Any> getMeta(key: MetaKey<T>): T? {
+        return meta[key] as? T
+    }
+
+    fun <T : Any> setMeta(key: MetaKey<T>, value: T) {
+        meta[key] = value
+    }
+
+    fun resolveReference(label: String): LispData? =
+        variables[label] ?: parent?.resolveReference(label)
+
+    fun setValueLocal(label: String, value: LispData): LispData {
+        variables[label] = value
+        return value
+    }
+
+    fun fork(): StackFrame {
+        return StackFrame(this)
+    }
+
+
+}