+struct psi_token;
+struct psi_let_exp;
+struct psi_call_frame;
+struct psi_impl;
+
+struct psi_let_stmt {
+ struct psi_token *token;
+ struct psi_let_exp *exp;
+};
+
+struct psi_let_stmt *psi_let_stmt_init(struct psi_let_exp *exp);
+void psi_let_stmt_free(struct psi_let_stmt **stmt_ptr);
+void psi_let_stmt_dump(int fd, struct psi_let_stmt *stmt);
+
+void *psi_let_stmt_exec(struct psi_let_stmt *stmt, struct psi_call_frame *frame);
+bool psi_let_stmts_validate(struct psi_data *data, struct psi_impl *impl);