input_stream
static struct input_stream *
struct input_stream *istream;
free_input_stream(struct input_stream *istream)
static struct input_stream *
struct input_stream *istream;
static struct input_stream *current; /* the input_stream being parsed. */
static struct input_stream *new_input_file(const char *, FILE *);
static struct input_stream *new_input_string(char *, const Location *);
static void free_input_stream(struct input_stream *);