Boolean open_first_file(void);
const char *input_file_name(unsigned file_number);
unsigned current_file_number(void);
+Boolean seek_to_begin(void);
+Boolean at_end_of_input(void);
Boolean open_eco_file(const char *eco_file);
int yywrap(void);
void add_filename_to_source_list(const char *filename,SourceFileType file_type);