diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 2e57449..f3a180f 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -8,6 +8,7 @@ add_library(imp
   prim.c
   print.c
   read.c
+  repl.c
   store.c
   token.c
 )
diff --git a/lib/include/repl.h b/lib/include/repl.h
new file mode 100644
index 0000000..30fa4b2
--- /dev/null
+++ b/lib/include/repl.h
@@ -0,0 +1,16 @@
+#ifndef REPL_H
+#define REPL_H
+
+#include "am.h"
+
+#define REPL_IO_BUFFER_SIZE 256U
+
+typedef struct {
+	am_t am;
+	char io_buffer[REPL_IO_BUFFER_SIZE];
+} repl_t;
+
+void repl_init(repl_t *repl);
+int repl_run(repl_t *repl);
+
+#endif
diff --git a/lib/repl.c b/lib/repl.c
new file mode 100644
index 0000000..c84904f
--- /dev/null
+++ b/lib/repl.c
@@ -0,0 +1,58 @@
+#include "repl.h"
+
+#include "eval.h"
+#include "memory_stream.h"
+#include "print.h"
+#include "read.h"
+
+#include <assert.h>
+#include <stdio.h>
+
+#define PROMPT "> "
+
+static int read_line(char buffer[REPL_IO_BUFFER_SIZE])
+{
+	for (unsigned i = 0; i < REPL_IO_BUFFER_SIZE; ++i) {
+		const int c = getchar();
+		switch (c) {
+		case EOF:
+			return EOF;
+		case '\n':
+			return (int)i;
+		default:
+			buffer[i] = (char)c;
+			break;
+		}
+	}
+	assert(false);
+	return -2;
+}
+
+void repl_init(repl_t *repl)
+{
+	am_init(&repl->am);
+}
+
+int repl_run(repl_t *repl)
+{
+	int len;
+	memory_stream_t input;
+
+	while (true) {
+		fputs(PROMPT, stdout);
+
+		len = read_line(repl->io_buffer);
+		if (len < 0) {
+			fputc('\n', stdout);
+			return 0;
+		}
+		memory_stream_init(&input, (const uint8_t *)repl->io_buffer, len);
+		read(&repl->am, (stream_t *)&input);
+
+		eval(&repl->am);
+
+		len = print(&repl->am, repl->io_buffer, REPL_IO_BUFFER_SIZE - 1);
+		repl->io_buffer[len] = '\n';
+		fwrite(repl->io_buffer, 1, len + 1, stdout);
+	}
+}