diff --git a/include/debug.h b/include/debug.h
index f4d9fe7..f0bcdcd 100644
--- a/include/debug.h
+++ b/include/debug.h
@@ -2,7 +2,9 @@
 #define LIBABACUS_DEBUG_H
 
 #include "tree.h"
+#include <stdio.h>
 
+void libab_debug_fprint_tree(libab_tree* print, FILE* file);
 void libab_debug_print_tree(libab_tree* print);
 
 #endif
diff --git a/src/debug.c b/src/debug.c
index e39158d..c3038b2 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -1,5 +1,4 @@
 #include "debug.h"
-#include <stdio.h>
 
 int _debug_foreach_print_tree(void* data, va_list args);
 
@@ -19,30 +18,35 @@ const char* _debug_node_name(libab_tree_variant var) {
     return names[var];
 }
 
-void _debug_print_tree_node(libab_tree* tree) {
-    printf("%s", _debug_node_name(tree->variant));
+void _debug_print_tree_node(libab_tree* tree, FILE* file) {
+    fprintf(file, "%s", _debug_node_name(tree->variant));
     if(libab_tree_has_string(tree->variant)) {
-        printf(": %s", tree->string_value);
+        fprintf(file, ": %s", tree->string_value);
     }
-    printf("\n");
+    fprintf(file, "\n");
 }
 
-void _debug_print_tree(libab_tree* tree, int depth) {
+void _debug_print_tree(libab_tree* tree, FILE* file, int depth) {
     int i = depth;
     while(i--) printf("  ");
-    _debug_print_tree_node(tree);
+    _debug_print_tree_node(tree, file);
     if(libab_tree_has_vector(tree->variant)) {
         vec_foreach(&tree->children, NULL, compare_always,
-                _debug_foreach_print_tree, depth + 1);
+                _debug_foreach_print_tree, file, depth + 1);
     }
 }
 
 int _debug_foreach_print_tree(void* data, va_list args) {
+    FILE* file = va_arg(args, FILE*);
     int depth = va_arg(args, int);
-    _debug_print_tree(data, depth);
+    _debug_print_tree(data, file, depth);
     return 0;
 }
 
-void libab_debug_print_tree(libab_tree* print) {
-    _debug_print_tree(print, 0);
+void libab_debug_fprint_tree(libab_tree* print, FILE* file) {
+    _debug_print_tree(print, file, 0);
+}
+
+void libab_debug_print_tree(libab_tree* print) {
+    _debug_print_tree(print, stdout, 0);
 }