1 files changed, 23 insertions, 0 deletions
diff --git a/src/OutputCapture.kt b/src/OutputCapture.kt
new file mode 100644
index 0000000..7fc8849
--- /dev/null
+++ b/src/OutputCapture.kt
@@ -0,0 +1,23 @@
+package moe.nea.lisp
+
+object OutputCapture {
+    data class CapturedOutput(
+        internal var string: StringBuilder,
+    ) {
+        val asString get() = string.toString()
+    }
+
+    object Meta : StackFrame.MetaKey<CapturedOutput>
+
+    fun captureOutput(stackFrame: StackFrame): CapturedOutput {
+        val output = CapturedOutput(StringBuilder())
+        stackFrame.setMeta(Meta, output)
+        return output
+    }
+
+    fun print(stackFrame: StackFrame, text: String) {
+        val output = stackFrame.getMeta(Meta)
+        output?.string?.append(text)
+        print(text)
+    }
+}
+\ No newline at end of file