diff --git a/lib/c/pervasives.h b/lib/c/pervasives.h
index 720f3f1..df8afbe 100644
--- a/lib/c/pervasives.h
+++ b/lib/c/pervasives.h
@@ -34,6 +34,7 @@
 #include <string.h>
 
 typedef float real;
+typedef char *string;
 
 /* between(i, n) returns idx between 0 and n-1. */
 static inline int between(int idx, int n)