diff --git a/fn.h b/fn.h
index 6ce961c..d6a5552 100644
--- a/fn.h
+++ b/fn.h
@@ -3,6 +3,10 @@
 Object* nextexpr(FILE*);
 void skipline(FILE*);
 
+/* repl.c */
+void repl(Object *env, FILE*, char *pre);
+void readlibs(char *argv[], Object *env);
+
 /* eval.c */
 Object* eval(Object *env, Object *expr);
 
diff --git a/main.c b/main.c
index e9dc0c2..799fbdb 100644
--- a/main.c
+++ b/main.c
@@ -1,37 +1,8 @@
 #include "dat.h"
 #include "fn.h"
-#include <setjmp.h>
-#include <stdarg.h>
-#include <stdlib.h>
 
-jmp_buf err;
 GC *gc;
 
-void
-panic(char *fmt, ...)
-{
-	va_list ap;
-	va_start(ap, fmt);
-	vfprintf(stderr, fmt, ap);
-	va_end(ap);
-	fprintf(stderr, "\n");
-	exit(1);
-}
-
-void
-error(char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	fprintf(stderr, "ERROR => ");
-	vfprintf(stderr, fmt, ap);
-	va_end(ap);
-	fprintf(stderr, "\n");
-	longjmp(err, 1);
-	exit(1);
-}
-
 static void
 SExprint(Object *obj)
 {
@@ -88,33 +59,11 @@ printexpr(Object *obj)
 	printf("\n");
 }
 
-static void
-loop(Object *env, FILE *f)
-{
-	if(setjmp(err) == 1){
-		if(feof(f))
-			return;
-		skipline(f);
-	}
-	while(1){
-		printf(">> ");
-		Object *res = nextexpr(f);
-		res = eval(env, res);
-		printexpr(res);
-		printgc("status", gc);
-	}
-}
-
 int
 main(int argc, char *argv[])
 {
 	gc = newgc(&argc, 400);
 	Object *env = newenv(gc, &Nil, &Nil, &Nil);
-	for(int i = 1; i < argc; ++i){
-		FILE *f = fopen(argv[i], "r");
-		if(f == 0)
-			panic("can't open %s", argv[i]);
-		loop(env, f);
-	}
-	loop(env, stdin);
+	readlibs(argv + 1, env);
+	repl(env, stdin, ">> ");
 }
diff --git a/makefile b/makefile
index 59335fd..3b13e26 100644
--- a/makefile
+++ b/makefile
@@ -1,6 +1,7 @@
 NAME=lisp
 OFILES=\
 	bltin.o\
+	repl.o\
 	eval.o\
 	main.o\
 	gc.o\
diff --git a/repl.c b/repl.c
new file mode 100644
index 0000000..ee4a2ed
--- /dev/null
+++ b/repl.c
@@ -0,0 +1,63 @@
+#include "dat.h"
+#include "fn.h"
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+jmp_buf *errptr;
+
+void
+panic(char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	fprintf(stderr, "\n");
+	exit(1);
+}
+
+void
+error(char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fprintf(stderr, "ERROR => ");
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	fprintf(stderr, "\n");
+	longjmp(*errptr, 1);
+	exit(1);
+}
+
+void
+repl(Object *env, FILE *f, char *pre)
+{
+	jmp_buf err;
+	errptr = &err;
+	if(setjmp(err) == 1){
+		if(feof(f))
+			return;
+		skipline(f);
+	}
+	while(1){
+		printf(pre);
+		Object *res = nextexpr(f);
+		res = eval(env, res);
+		printexpr(res);
+		printgc("status", gc);
+	}
+}
+
+void 
+readlibs(char *argv[], Object *env)
+{
+	for(;*argv; argv++){
+		FILE *f = fopen(*argv, "r");
+		if(f == 0)
+			panic("can't open %s", *argv);
+		repl(env, f, "");
+		printf("\n");
+	}
+}