<b_jonas> learn Silent initial consonants in English are: write, wrong, wrist, wrap, wreck, wrest, wrestle, wriggle, wrinkle, wrath, wraith, wreath, wrangle, wren, wright, wrought, wring, writ, writhe, wry; know, knife, knock, knee, knight, knob, knot, knit, knack, knout, knuckle; psychology, psalm, pseudo, psychic, psionics; gnaw, gnash, gnome, gnu, gnat; pneumatic; mnemonic; chthonic; phthisis; bdellium.

#ifndef SUB_H_
#define SUB_H_

#include "config.h"

#include <stddef.h>

struct expr;
struct sub;

struct sub *sub_new(const struct expr *);
struct sub *sub_incr(struct sub *);
void sub_decr(struct sub *);
ATTR_PURE
struct expr *sub_expr(const struct sub *);
size_t sub_id(const struct sub *);

#endif /* SUB_H_ */