#!/usr/bin/env python3
-from __future__ import annotations
+# © Copyright 2021-2022, Scott Gasch
-from collections import defaultdict
+"""This is a module concerned with the creation of and searching of a
+corpus of documents. The corpus and index are held in memory.
+"""
+
+from __future__ import annotations
import enum
import sys
-from typing import (
- Any,
- Dict,
- List,
- NamedTuple,
- Optional,
- Set,
- Sequence,
- Tuple,
- Union,
-)
+from collections import defaultdict
+from dataclasses import dataclass, field
+from typing import Any, Dict, List, Optional, Sequence, Set, Tuple, Union
class ParseError(Exception):
"""An error encountered while parsing a logical search expression."""
def __init__(self, message: str):
+ super().__init__()
self.message = message
-class Document(NamedTuple):
- """A tuple representing a searchable document."""
+@dataclass
+class Document:
+ """A class representing a searchable document."""
+
+ docid: str = ''
+ """A unique identifier for each document -- must be provided
+ by the caller. See :meth:`python_modules.id_generator.get` or
+ :meth:`python_modules.string_utils.generate_uuid` for potential
+ sources."""
+
+ tags: Set[str] = field(default_factory=set)
+ """A set of tag strings for this document. May be empty. Tags
+ are simply text labels that are associated with a document and
+ may be used to search for it later.
+ """
- docid: str # a unique idenfier for the document
- tags: Set[str] # an optional set of tags
- properties: List[
- Tuple[str, str]
- ] # an optional set of key->value properties
- reference: Any # an optional reference to something else
+ properties: List[Tuple[str, str]] = field(default_factory=list)
+ """A list of key->value strings for this document. May be empty.
+ Properties are more flexible tags that have both a label and a
+ value. e.g. "category:mystery" or "author:smith"."""
+
+ reference: Optional[Any] = None
+ """An optional reference to something else for convenience;
+ interpreted only by caller code, ignored here.
+ """
class Operation(enum.Enum):
class Corpus(object):
- """A collection of searchable documents."""
+ """A collection of searchable documents. The caller can
+ add documents to it (or edit existing docs) via :meth:`add_doc`,
+ retrieve a document given its docid via :meth:`get_doc`, and
+ perform various lookups of documents. The most interesting
+ lookup is implemented in :meth:`query`.
+
+ >>> c = Corpus()
+ >>> c.add_doc(Document(
+ ... docid=1,
+ ... tags=set(['urgent', 'important']),
+ ... properties=[
+ ... ('author', 'Scott'),
+ ... ('subject', 'your anniversary')
+ ... ],
+ ... reference=None,
+ ... )
+ ... )
+ >>> c.add_doc(Document(
+ ... docid=2,
+ ... tags=set(['important']),
+ ... properties=[
+ ... ('author', 'Joe'),
+ ... ('subject', 'your performance at work')
+ ... ],
+ ... reference=None,
+ ... )
+ ... )
+ >>> c.add_doc(Document(
+ ... docid=3,
+ ... tags=set(['urgent']),
+ ... properties=[
+ ... ('author', 'Scott'),
+ ... ('subject', 'car turning in front of you')
+ ... ],
+ ... reference=None,
+ ... )
+ ... )
+ >>> c.query('author:Scott and important')
+ {1}
+ >>> c.query('*')
+ {1, 2, 3}
+ >>> c.query('*:*')
+ {1, 2, 3}
+ >>> c.query('*:Scott')
+ {1, 3}
+ """
def __init__(self) -> None:
self.docids_by_tag: Dict[str, Set[str]] = defaultdict(set)
- self.docids_by_property: Dict[Tuple[str, str], Set[str]] = defaultdict(
- set
- )
+ self.docids_by_property: Dict[Tuple[str, str], Set[str]] = defaultdict(set)
self.docids_with_property: Dict[str, Set[str]] = defaultdict(set)
self.documents_by_docid: Dict[str, Document] = {}
distinct docid that will serve as its primary identifier. If
the same Document is added multiple times, only the most
recent addition is indexed. If two distinct documents with
- the same docid are added, the latter klobbers the former in the
- indexes.
+ the same docid are added, the latter klobbers the former in
+ the indexes. See :meth:`python_modules.id_generator.get` or
+ :meth:`python_modules.string_utils.generate_uuid` for potential
+ sources of docids.
Each Document may have an optional set of tags which can be
- used later in expressions to the query method.
+ used later in expressions to the query method. These are simple
+ text labels.
Each Document may have an optional list of key->value tuples
which can be used later in expressions to the query method.
never interpreted by this module. This is meant to allow easy
mapping between Documents in this corpus and external objects
they may represent.
+
+ Args:
+ doc: the document to add or edit
"""
if doc.docid in self.documents_by_docid:
self.docids_with_property[key].add(doc.docid)
def get_docids_by_exact_tag(self, tag: str) -> Set[str]:
- """Return the set of docids that have a particular tag."""
+ """Return the set of docids that have a particular tag.
+ Args:
+ tag: the tag for which to search
+
+ Returns:
+ A set containing docids with the provided tag which
+ may be empty."""
return self.docids_by_tag[tag]
def get_docids_by_searching_tags(self, tag: str) -> Set[str]:
- """Return the set of docids with a tag that contains a str"""
+ """Return the set of docids with a tag that contains a str.
+
+ Args:
+ tag: the tag pattern for which to search
+ Returns:
+ A set containing docids with tags that match the pattern
+ provided. e.g., if the arg was "foo" tags "football", "foobar",
+ and "food" all match.
+ """
ret = set()
for search_tag in self.docids_by_tag:
if tag in search_tag:
def get_docids_with_property(self, key: str) -> Set[str]:
"""Return the set of docids that have a particular property no matter
what that property's value.
- """
+ Args:
+ key: the key value to search for.
+
+ Returns:
+ A set of docids that contain the key (no matter what value)
+ which may be empty.
+ """
return self.docids_with_property[key]
def get_docids_by_property(self, key: str, value: str) -> Set[str]:
"""Return the set of docids that have a particular property with a
- particular value..
- """
+ particular value.
+ Args:
+ key: the key to search for
+ value: the value that key must have in order to match a doc.
+
+ Returns:
+ A set of docids that contain key with value which may be empty.
+ """
return self.docids_by_property[(key, value)]
def invert_docid_set(self, original: Set[str]) -> Set[str]:
"""Invert a set of docids."""
-
- return set(
- [
- docid
- for docid in self.documents_by_docid.keys()
- if docid not in original
- ]
- )
+ return {docid for docid in self.documents_by_docid if docid not in original}
def get_doc(self, docid: str) -> Optional[Document]:
- """Given a docid, retrieve the previously added Document."""
+ """Given a docid, retrieve the previously added Document.
+
+ Args:
+ docid: the docid to retrieve
+ Returns:
+ The Document with docid or None to indicate no match.
+ """
return self.documents_by_docid.get(docid, None)
def query(self, query: str) -> Optional[Set[str]]:
"""Query the corpus for documents that match a logical expression.
- Returns a (potentially empty) set of docids for the matching
- (previously added) documents or None on error.
- e.g.
+ Args:
+ query: the logical query expressed using a simple language
+ that understands conjunction (and operator), disjunction
+ (or operator) and inversion (not operator) as well as
+ parenthesis. Here are some legal sample queries::
- tag1 and tag2 and not tag3
+ tag1 and tag2 and not tag3
- (tag1 or tag2) and (tag3 or tag4)
+ (tag1 or tag2) and (tag3 or tag4)
- (tag1 and key2:value2) or (tag2 and key1:value1)
+ (tag1 and key2:value2) or (tag2 and key1:value1)
- key:*
+ key:*
- tag1 and key:*
+ tag1 and key:*
+
+ Returns:
+ A (potentially empty) set of docids for the matching
+ (previously added) documents or None on error.
"""
try:
return operator_precedence(token) is not None
def lex(query: str):
- query = query.lower()
tokens = query.split()
for token in tokens:
# Handle ( and ) operators stuck to the ends of tokens
operation = Operation.from_token(token)
operand_count = operation.num_operands()
if len(node_stack) < operand_count:
- raise ParseError(
- f"Incorrect number of operations for {operation}"
- )
+ raise ParseError(f"Incorrect number of operations for {operation}")
for _ in range(operation.num_operands()):
args.append(node_stack.pop())
node = Node(corpus, operation, args)
ok = True
break
if not ok:
- raise ParseError(
- "Unbalanced parenthesis in query expression"
- )
+ raise ParseError("Unbalanced parenthesis in query expression")
# and, or, not
else:
try:
key, value = tag.split(":")
except ValueError as v:
- raise ParseError(
- f'Invalid key:value syntax at "{tag}"'
- ) from v
- if value == "*":
- r = self.corpus.get_docids_with_property(key)
+ raise ParseError(f'Invalid key:value syntax at "{tag}"') from v
+
+ if key == '*':
+ r = set()
+ for kv, s in self.corpus.docids_by_property.items():
+ if value in ('*', kv[1]):
+ r.update(s)
else:
- r = self.corpus.get_docids_by_property(key, value)
+ if value == '*':
+ r = self.corpus.get_docids_with_property(key)
+ else:
+ r = self.corpus.get_docids_by_property(key, value)
else:
- r = self.corpus.get_docids_by_exact_tag(tag)
+ if tag == '*':
+ r = set()
+ for s in self.corpus.docids_by_tag.values():
+ r.update(s)
+ else:
+ r = self.corpus.get_docids_by_exact_tag(tag)
retval.update(r)
else:
raise ParseError(f"Unexpected query {tag}")
elif self.op is Operation.DISJUNCTION:
if len(evaled_operands) != 2:
- raise ParseError(
- "Operation.DISJUNCTION (or) expects two operands."
- )
+ raise ParseError("Operation.DISJUNCTION (or) expects two operands.")
retval.update(evaled_operands[0])
retval.update(evaled_operands[1])
elif self.op is Operation.CONJUNCTION:
if len(evaled_operands) != 2:
- raise ParseError(
- "Operation.CONJUNCTION (and) expects two operands."
- )
+ raise ParseError("Operation.CONJUNCTION (and) expects two operands.")
retval.update(evaled_operands[0])
retval = retval.intersection(evaled_operands[1])
elif self.op is Operation.INVERSION:
if len(evaled_operands) != 1:
- raise ParseError(
- "Operation.INVERSION (not) expects one operand."
- )
+ raise ParseError("Operation.INVERSION (not) expects one operand.")
_ = evaled_operands[0]
if isinstance(_, set):
retval.update(self.corpus.invert_docid_set(_))
else:
raise ParseError(f"Unexpected negation operand {_} ({type(_)})")
return retval
+
+
+if __name__ == '__main__':
+ import doctest
+
+ doctest.testmod()
projects / python_utils.git / blobdiff