Upversioned the C source tree to '0.0.7-SNAPSHOT', but proposing to start experimental

work towards 0.1.0 in separate source trees.

src/c/ops/equal.h

@@ -0,0 +1,36 @@
+/**
+ * equal.h
+ *
+ * Checks for shallow and deep equality
+ *
+ * (c) 2017 Simon Brooke <simon@journeyman.cc>
+ * Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#include <math.h>
+#include <stdbool.h>
+
+#include "consspaceobject.h"
+
+#ifndef __equal_h
+#define __equal_h
+
+/** 
+ * size of buffer for assembling strings. Likely to be useful to
+ * read, too.
+ */
+#define STRING_SHIPYARD_SIZE 1024
+
+/**
+ * Shallow, and thus cheap, equality: true if these two objects are 
+ * the same object, else false.
+ */
+bool eq( struct cons_pointer a, struct cons_pointer b );
+
+/**
+ * Deep, and thus expensive, equality: true if these two objects have
+ * identical structure, else false.
+ */
+bool equal( struct cons_pointer a, struct cons_pointer b );
+
+#endif