__init__.py 24 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799
# This file is part of the Poliqarp suite.
#
# Copyright (C) 2009 by Instytut Podstaw Informatyki Polskiej
# Akademii Nauk (IPI PAN; Institute of Computer Science, Polish
# Academy of Sciences; cf. www.ipipan.waw.pl).  All rights reserved.
#
# This file may be distributed and/or modified under the terms of the
# GNU General Public License version 2 as published by the Free Software
# Foundation and appearing in the file gpl.txt included in the packaging
# of this file.  (See http://www.gnu.org/licenses/translations.html for
# unofficial translations.)
#
# A commercial license is available from IPI PAN (contact
# Michal.Ciesiolka@ipipan.waw.pl or ipi@ipipan.waw.pl for more
# information).  Licensees holding a valid commercial license from IPI
# PAN may use this file in accordance with that license.
#
# This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING
# THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE.

'''
Interface to Poliqarp daemon.
'''

import socket
import re
import datetime

from poliqarp.errors import ProtocolViolation, ProtocolError, InvalidQuery, SystemOpenError, Busy, protocol_error

DEBUG = False

def debug(s):
    import sys
    sys.stderr.write(s)

DEFAULT_HOST = '127.0.0.1'
DEFAULT_PORT = 4567

MAX_CONTEXT_SEGMENTS = 20
MAX_WCONTEXT_SEGMENTS = 200

class AsynchronousMessageExpected(Exception):
    pass

class UnsupportedCommand(Exception):
    pass

class Timeout(Exception):
    pass

class QueryRunning(Exception):
    pass

class EmptyQuery(ProtocolError):
    message = 'Query is empty'

JOB_NO = 0
JOB_RUNNING = 1
JOB_DONE = 2

class Date(object):

    def __init__(self, year=None, month=None, day=None):
        datetime.date(year or 2000, month or 1, day or 1)
        self.year = year or None
        self.month = month or None
        self.day = day or None

    def __str__(self):
        result = [self.year, self.month, self.day]
        while result[-1] is None:
            del result[-1]
        for i, n_digits in enumerate((4, 2, 2)):
            try:
                if result[i]:
                    result[i] = '%0*d' % (n_digits, result[i])
                else:
                    result[i] = '?' * n_digits
            except IndexError:
                break
        return '-'.join(result)

    def __cmp__(self, other):
        return cmp((self.year, self.month, self.day), (other.year, other.month, other.day))

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__, ', '.join(
            '%s=%r' % (key, value)
            for key in ('year', 'month', 'day')
            for value in (getattr(self, key),) if value is not None
        ))

class Connection(object):

    def __init__(self, host=DEFAULT_HOST, port=DEFAULT_PORT):
        host = str(host)
        port = str(port)
        if port.isdigit():
            port = int(port)
        else:
            port = socket.getservbyname(port)
        self._address = host, port
        self._invalidate_corpus()
        self._session_id = None
        self._socket = self._file = None

    @property
    def socket(self):
        if self._socket is None:
            s = self._socket = socket.socket()
            s.connect(self._address)
        return self._socket

    @property
    def file(self):
        if self._file is None:
            self._file = self.socket.makefile()
        return self._file

    def __getstate__(self):
        self._n_stored_results = None
        if self._socket is not None or self._file is not None:
            raise ValueError('Cannot pickle an active connection')
        return self.__dict__

    def __setstate__(self, state):
        self.__dict__.update(state)

    def _put(self, s):
        self.file.write(s)
        self.file.write('\n')
        self.file.flush()
        if DEBUG:
            debug('> %s\n' % s)

    def _set_timeout(self, timeout):
        self.socket.settimeout(timeout)

    def _reset_timeout(self):
        self._set_timeout(None)

    def _handle_async_message(self, message):
        if message == 'OPENED':
            self._open_status = JOB_DONE
        elif message.startswith('OPENFAIL '):
            self._open_status = JOB_NO
            self._open_path = None
            try:
                raise protocol_error(message[9:])
            except SystemOpenError, ex:
                message = self.get_last_error()
                if message is None:
                    raise ProtocolViolation
                ex.message = message
                raise
        elif message == 'NEW-RESULTS':
            self._n_stored_results = None
        elif message == 'SORTED':
            self._sort_status = JOB_DONE
        elif message.startswith('QUERY-DONE '):
            self._query_status = JOB_DONE
            self._n_stored_results = int(message[10:])
        else:
            raise ProtocolViolation

    def _get_async_message(self, timeout=None):
        self._set_timeout(timeout)
        try:
            try:
                r = self.file.readline()[:-1]
            except socket.timeout:
                raise Timeout
        finally:
            self._reset_timeout()
        if DEBUG:
            debug('< %s\n' % r)
        if r.startswith('M '):
            self._handle_async_message(r[2:])
        elif r.startswith('R '):
            raise AsynchronousMessageExpected
        else:
            raise ProtocolViolation

    def _get_text(self):
        while True:
            r = self.file.readline()[:-1]
            if DEBUG:
                debug('< %s\n' % r)
            if r.startswith('R '):
                return r[2:].decode('UTF-8')
            elif r.startswith('M '):
                self._handle_async_message(r[2:])
            else:
                raise ProtocolViolation

    def _get_reply(self):
        while True:
            r = self.file.readline()[:-1]
            if DEBUG:
                debug('< %s\n' % r)
            if r.startswith('R '):
                r = r[2:]
                if r.startswith('ERR '):
                    raise protocol_error(r[4:])
                elif r == 'UNSUPPORTED':
                    raise UnsupportedCommand()
                else:
                    return r
            elif r.startswith('M '):
                self._handle_async_message(r[2:])
            else:
                raise ProtocolViolation(r)

    def ping(self):
        self._put('PING')
        if self._get_reply() != 'PONG':
            raise ProtocolViolation

    def get_version(self):
        self._put('GET-VERSION')
        return self._get_reply()

    def get_default_session_name(self):
        return self.socket.getsockname()[0]

    '''
    Create new or resume existing session.

    Returns session id if a new session was created.
    '''
    def make_session(self, name=None, session_id=None):
        if name is None:
            name = self.get_default_session_name()
        if session_id is None:
            session_id = self._session_id
        new_session = session_id is None
        if new_session:
            command = 'MAKE-SESSION %s' % name
        else:
            command = 'RESUME-SESSION %s %s' % (session_id, name)
        self._put(command)
        r = self._get_reply()
        if not new_session:
            if r != 'OK':
                raise ProtocolViolation
        else:
            if r.startswith('OK '):
                session_id = r[3:]
            else:
                raise ProtocolViolation
        self._session_id = session_id
        if new_session:
            return session_id

    def close_session(self):
        self._put('CLOSE-SESSION')
        if self._get_reply() != 'OK':
            raise ProtocolViolation
        self._session_id = None

    def suspend_session(self):
        self._put('SUSPEND-SESSION')
        if self._get_reply() != 'OK':
            raise ProtocolViolation

    def open_corpus(self, path, timeout=None):
        path = str(path)
        if '\n' in path:
            raise ValueError
        if self._open_status == JOB_DONE and path != self._open_path:
            self.close_corpus()
        if self._open_status == JOB_NO:
            self._put('OPEN-CORPUS %s' % path)
            r = self._get_reply()
            if r != 'OK':
                raise ProtocolViolation
            self._open_path = path
            if self._open_status == JOB_NO:
                self._open_status = JOB_RUNNING
        else:
            if path != self._open_path:
                raise NotImplementedError # FIXME
            if self._open_status == JOB_DONE:
                return
        self._get_async_message(timeout=timeout)
        if self._open_status != JOB_DONE:
            raise ProtocolViolation

    def _invalidate_query(self):
        self._query = None
        self._query_status = JOB_NO
        self._sort_id = None
        self._sort_status = JOB_NO
        self._column_types = None
        self._n_stored_results = None

    def _invalidate_corpus(self):
        self._open_status = JOB_NO
        self._open_path = None
        self._invalidate_query()

    def close_corpus(self):
        self._put('CLOSE-CORPUS')
        r = self._get_reply()
        if r != 'OK':
            raise ProtocolViolation
        self._invalidate_corpus()

    def get_corpus_statistics(self):
        self._put('GET-CORPUS-STATS')
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation
        try:
            num_segments, num_types, num_lemmata, num_tags = map(int, r[3:].split())
        except ValueError:
            raise ProtocolViolation(r)
        return num_segments, num_types, num_lemmata, num_tags

    def get_job_status(self):
        self._put('GET-JOB-STATUS')
        r = self._get_reply()
        if r.startswith('OK '):
            try:
                return int(r[3:])
            except ValueError:
                pass
        raise ProtocolViolation(r)

    def cancel_job(self):
        self._put('CANCEL-JOB')
        r = self._get_reply()
        if r != 'OK':
            raise ProtocolViolation(r)

    def make_query(self, query, force=False):
        if not isinstance(query, unicode):
            query = query.decode('UTF-8', 'replace')
        query = query.encode('UTF-8', 'replace')
        query = re.sub('[\x00-\x1f]', ' ', query) # Don't trust user-supplied data.
        if not query:
            raise EmptyQuery
        if query == self._query and not force:
            return
        if self._query_status == JOB_RUNNING:
            raise Busy
        self._invalidate_query()
        self._put('MAKE-QUERY %s' % query)
        try:
            r = self._get_reply()
            if r != 'OK':
                raise ProtocolViolation(r)
        except InvalidQuery, ex:
            message = self.get_last_error()
            if message is None:
                raise ProtocolViolation
            ex.message = message
            raise
        self._query = query

    def get_n_stored_results(self):
        n = self._n_stored_results
        if n is None:
            capacity, n = self.get_buffer_state()
            self._n_stored_results = n
        return n

    def get_n_spotted_results(self):
        self._put('GET-NUM-RESULTS')
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation(r)
        try:
            n, = map(int, r[3:].split(None, 1))
        except ValueError:
            raise ProtocolViolation(r)
        return n

    def run_query(self, n, m=None, timeout=None, force=False):
        if m is None:
            m = n
        if force:
            if self._query_status == JOB_DONE:
                self._query_status = JOB_NO
            elif self._query_status == JOB_RUNNING:
                raise Busy
        if self._query_status == JOB_DONE:
            return
        elif self._query_status == JOB_NO:
            self._put('RUN-QUERY %d' % n)
            r = self._get_reply()
            if r != 'OK':
                raise ProtocolViolation(r)
            if self._query_status == JOB_NO:
                self._query_status = JOB_RUNNING
        assert self._query_status == JOB_RUNNING
        while self.get_n_stored_results() < m and self._query_status == JOB_RUNNING:
            try:
                self._get_async_message(timeout=timeout)
            except Timeout:
                break
            # FIXME: Ideally, we should update timeout here.
            # But if we don't, we must break the loop right now:
            break
        if self._query_status == JOB_RUNNING:
            raise QueryRunning

    def _get_result_segment(self, ct):
        orth = self._get_text()
        have_interps = ct.has_lemmata or ct.has_tags
        if have_interps:
            interps = []
        else:
            interps = None
        segment = Segment(orth, interps)
        if not have_interps:
            return segment
        r = self._get_reply()
        try:
            m = int(r)
        except ValueError:
            raise ProtocolViolation(m)
        if type(m) != int:
            raise ProtocolViolation(r)
        for j in xrange(m):
            lemma = tag = None
            if ct.has_lemmata:
                lemma = self._get_text()
            if ct.has_tags:
                tag = self._get_text()
            segment.add_interp(lemma=lemma, tag=tag)
        if ct.has_ids:
            segment.id = int(self._get_text())
        return segment

    def _get_result_column(self, ct):
        r = self._get_reply()
        try:
            n = int(r)
        except ValueError:
            raise ProtocolViolation(r)
        if type(n) != int:
            raise ProtocolViolation(r)
        return ct, [self._get_result_segment(ct) for i in xrange(n)]

    def _get_result(self, column_types):
        return [self._get_result_column(ct) for ct in column_types]

    def get_results(self, i, j):
        column_types = self.get_column_types()
        i = int(i)
        j = int(j)
        if i < 0:
            raise ValueError
        if j < i:
            return []
        self._put('GET-RESULTS %d %d' % (i, j))
        r = self._get_reply()
        if r != 'OK':
            raise ProtocolViolation(r)
        return [self._get_result(column_types) for k in xrange(i, j + 1)]

    def get_context(self, i):
        self._put('GET-CONTEXT %d' % i)
        r = self._get_reply()
        if r != 'OK':
            raise ProtocolViolation(r)
        r = tuple(self._get_text() for k in xrange(4))
        return r

    def get_metadata_types(self):
        self._put('GET-METADATA-TYPES')
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation(r)
        try:
            n = int(r[3:])
        except ValueError:
            raise ProtocolViolation(r)
        if type(n) != int:
            raise ProtocolViolation(r)
        try:
            result = dict(
                (key, dict(T=unicode, D=Date)[type])
                for i in xrange(n)
                for type, key in [self._get_text().split(None, 1)]
            )
        except KeyError, ex:
            raise ProtocolViolation(ex[0])
        return result

    def _get_metadata_value(self):
        r = self._get_text()
        if r == 'U':
            return
        if len(r) < 2 or r[1] != ' ':
            raise ProtocolViolation(r)
        if r[0] == 'T':
            return r[2:]
        elif r[0] == 'D':
            try:
                y, m, d = map(int, r[2:].split())
                return Date(y, m, d)
            except ValueError:
                raise ProtocolViolation(r)
        else:
            raise ProtocolViolation(r)

    def get_metadata(self, i, dict_type=dict):
        self._put('GET-METADATA %d' % i)
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation(r)
        try:
            n = int(r[3:])
        except ValueError:
            raise ProtocolViolation(r)
        result = dict_type(
            (key, value)
            for i in xrange(n)
            for key in [self._get_text()]
            for value in [self._get_metadata_value()]
        )
        return result

    def sort(self, column_type, atergo=False, ascending=True, timeout=None):
        sort_id = column_type.sort_id[atergo]
        if ascending:
            sort_id = sort_id.upper()
        else:
            sort_id = sort_id.lower()
        if self._sort_status != JOB_RUNNING:
            self._sort_status = JOB_NO
            self._put('SORT-RESULTS %s' % sort_id)
            r = self._get_reply()
            if r != 'OK':
                raise ProtocolViolation(r)
            self._sort_id = sort_id
            if self._sort_status != JOB_DONE:
                self._sort_status = JOB_RUNNING
        else:
            if self._sort_id != sort_id:
                raise Busy
        self._get_async_message(timeout=timeout)
        if self._sort_status != JOB_DONE:
            raise ProtocolViolation
        return True

    def get_buffer_state(self):
        self._put('GET-BUFFER-STATE')
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation(r)
        try:
            capacity, used = map(int, r[3:].split(None, 1))
        except ValueError:
            raise ProtocolViolation(r)
        return capacity, used

    def shift_buffer(self, n):
        raise NotImplementedError

    def resize_buffer(self, n):
        self._put('RESIZE-BUFFER %d' % n)
        r = self._get_reply()
        if not r == 'OK':
            raise ProtocolViolation(r)
        self._n_stored_results = None

    def _set_option(self, name, value):
        self._put('SET-OPTION %s %s' % (name, value))
        r = self._get_reply()
        if r != 'OK':
            raise ProtocolViolation(r)

    def set_left_context_width(self, value):
        self._set_option('left-context-width', int(value))

    def set_right_context_width(self, value):
        self._set_option('right-context-width', int(value))

    def set_wide_context_width(self, value):
        self._set_option('wide-context-width', int(value))

    def set_retrieve_lemmata(self, left_context=False, left_match=False, right_context=False, right_match=False):
        value = ''.join(str(0 + bool(x)) for x in
            (left_context, left_match, right_context, right_match)
        )
        self._set_option('retrieve-lemmata', value)
        self._column_types = None

    def set_retrieve_tags(self, left_context=False, left_match=False, right_context=False, right_match=False):
        value = ''.join(str(0 + bool(x)) for x in
            (left_context, left_match, right_context, right_match)
        )
        self._set_option('retrieve-tags', value)
        self._column_types = None

    def set_retrieve_ids(self, left_context=False, left_match=False, right_context=False, right_match=False):
        value = ''.join(str(0 + bool(x)) for x in
            (left_context, left_match, right_context, right_match)
        )
        self._set_option('retrieve-ids', value)
        self._column_types = None

    def set_notification_interval(self, value):
        value = int(value)
        self._set_option('notification-interval', value)

    def set_query_flags(self, query_case_sensitive=True, query_whole_words=True, metadata_case_sensitive=False, metadata_whole_words=False):
        value = ''.join(str(1 - bool(x)) for x in
            (query_case_sensitive,
            query_whole_words,
            metadata_case_sensitive,
            metadata_whole_words)
        )
        self._set_option('query-flags', value)

    def set_disamb(self, value=True):
        self._set_option('disamb', 0 + bool(value))

    def set_rewrite(self, value):
        self._set_option('rewrite', value)

    def set_random_sample(self, value):
        self._set_option('random-sample', 0 + bool(value))

    def create_alias(self, name, value):
        raise NotImplementedError

    def delete_alias(self, name):
        raise NotImplementedError

    def get_aliases(self):
        raise NotImplementedError

    def get_tagset(self):
        self._put('GET-TAGSET')
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation(r)
        try:
            n_categories, n_classes = map(int, r[3:].split(None, 1))
        except ValueError:
            raise ProtocolViolation(r)
        categories = {}
        classes = {}
        for i in xrange(n_categories):
            r = self._get_reply()
            key, value = r.split(None, 1)
            value = frozenset(value.split())
            categories[key] = value
        for i in xrange(n_classes):
            r = self._get_reply()
            try:
                key, value = r.split(None, 1)
            except ValueError:
                key = r
                value = ()
            else:
                value = tuple(value.split())
            classes[key] = value
        return (categories, classes)

    def get_column_types(self):
        if self._column_types is not None:
            return self._column_types
        self._put('GET-COLUMN-TYPES')
        r = self._get_reply()
        if not r.startswith('OK '):
            raise ProtocolViolation(r)
        types = r[3:].split(':')
        types = (re.match('^([LR]C|[LR]?M)<(l?t?i?)>$', tp).groups() for tp in types)
        result = tuple(
            dict(
                LC = LeftContextType,
                LM = LeftMatchType,
                M  = MatchType,
                RM = RightMatchType,
                RC = RightContextType
            )[id](has_tags = 't' in flags, has_lemmata = 'l' in flags, has_ids = 'i' in flags)
            for id, flags in types
        )
        self._column_types = result
        return result

    def get_last_error(self):
        self._put('GET-LAST-ERROR')
        r = self._get_reply()
        if r.startswith('ERROR '):
            return r[6:]
        elif r == 'NOERROR':
            return None
        else:
            raise ProtocolViolation(r)

    def set_locale(self, locale):
        self._put('SET-LOCALE %s' % locale)
        r = self._get_reply()
        if r != 'OK':
            raise ProtocolViolation(r)

    def __enter__(self):
        return self

    def __exit__(self, *exc_info):
        self.close()

    def close(self):
        if self._socket is None:
            return
        self._socket.close()
        self._socket = None
        self._file = None

class ColumnType(object):

    def __init__(self, has_tags=False, has_lemmata=False, has_ids=False):
        self.has_tags = has_tags
        self.has_lemmata = has_lemmata
        self.has_ids = has_ids

    def __repr__(self):
        return '%s(%s)' % (
            self.__class__.__name__,
            ','.join(sorted(
                '%s=%s' % (key, value)
                for key, value in vars(self).iteritems()
                if key.startswith('has_')
            ))
        )

class ContextType(ColumnType):
    is_context = True
    is_match = False

class MatchType(ColumnType):
    is_context = False
    is_match = True
    is_left = None

class LeftMatchType(MatchType):
    sort_id = 'b', 'f'
    is_left = True
    is_right = False

class RightMatchType(MatchType):
    sort_id = 'c', 'g'
    is_right = True
    is_left = False

class LeftContextType(ContextType):
    sort_id = 'a', 'e'
    is_left = True
    is_right = False

class RightContextType(ContextType):
    sort_id = 'd', 'h'
    is_right = True
    is_left = False

class Segment(object):

    def __init__(self, orth, interps=None, id=None):
        self.id = id
        self.orth = orth
        if interps is None:
            self.interps = None
        else:
            self.interps = list(interps)

    def add_interp(self, lemma=None, tag=None, nth=None):
        if self.interps is None:
            raise ValueError
        self.interps += Interp(lemma=lemma, tag=tag),

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__, ', '.join(
            '%s=%r' % (key, value)
            for key in ('id', 'orth', 'interps')
            for value in (getattr(self, key),) if value is not None
        ))

class Interp(object):

    def __init__(self, lemma=None, tag=None):
        self.lemma = lemma
        self.tag = tag

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__, ', '.join(
            '%s=%r' % (key, value)
            for key in ('lemma', 'tag')
            for value in (getattr(self, key),) if value is not None
        ))

# vim:ts=4 sw=4 et