struct dnodeS; struct unodeS;
typedef void (*pull)(struct unodeS*);
typedef void (*push)(char, struct dnodeS *, struct unodeS*);
typedef struct dnodeS {push code; struct dnodeS* nsn;} dnode;
typedef struct unodeS {pull code; dnode* dn;} unode;

#include <setjmp.h>
jmp_buf trmp;
unode * ug;

#include <stdio.h>
dnode* carm(dnode*);
dnode* cinterleave(dnode*, unode*);
unode* crptr(dnode*, char);
dnode* ctee(dnode*, dnode*);
dnode* cx2uc(dnode*);
dnode* cprint(FILE*, int);
void start(unode*);
unode* conce(unode***);
unode* chllo(dnode*, char*);