sqlglot.helper API documentation

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# sqlglot.helper

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      1from __future__ import annotations
      2
      3import inspect
      4import logging
      5import re
      6import sys
      7import typing as t
      8from collections.abc import Collection
      9from contextlib import contextmanager
     10from copy import copy
     11from enum import Enum
     12from itertools import count
     13
     14if t.TYPE_CHECKING:
     15    from sqlglot import exp
     16    from sqlglot._typing import E, T
     17    from sqlglot.dialects.dialect import DialectType
     18    from sqlglot.expressions import Expression
     19
     20CAMEL_CASE_PATTERN = re.compile("(?<!^)(?=[A-Z])")
     21PYTHON_VERSION = sys.version_info[:2]
     22logger = logging.getLogger("sqlglot")
     23
     24
     25class AutoName(Enum):
     26    """This is used for creating enum classes where `auto()` is the string form of the corresponding value's name."""
     27
     28    def _generate_next_value_(name, _start, _count, _last_values):
     29        return name
     30
     31
     32def seq_get(seq: t.Sequence[T], index: int) -> t.Optional[T]:
     33    """Returns the value in `seq` at position `index`, or `None` if `index` is out of bounds."""
     34    try:
     35        return seq[index]
     36    except IndexError:
     37        return None
     38
     39
     40@t.overload
     41def ensure_list(value: t.Collection[T]) -> t.List[T]:
     42    ...
     43
     44
     45@t.overload
     46def ensure_list(value: T) -> t.List[T]:
     47    ...
     48
     49
     50def ensure_list(value):
     51    """
     52    Ensures that a value is a list, otherwise casts or wraps it into one.
     53
     54    Args:
     55        value: the value of interest.
     56
     57    Returns:
     58        The value cast as a list if it's a list or a tuple, or else the value wrapped in a list.
     59    """
     60    if value is None:
     61        return []
     62    if isinstance(value, (list, tuple)):
     63        return list(value)
     64
     65    return [value]
     66
     67
     68@t.overload
     69def ensure_collection(value: t.Collection[T]) -> t.Collection[T]:
     70    ...
     71
     72
     73@t.overload
     74def ensure_collection(value: T) -> t.Collection[T]:
     75    ...
     76
     77
     78def ensure_collection(value):
     79    """
     80    Ensures that a value is a collection (excluding `str` and `bytes`), otherwise wraps it into a list.
     81
     82    Args:
     83        value: the value of interest.
     84
     85    Returns:
     86        The value if it's a collection, or else the value wrapped in a list.
     87    """
     88    if value is None:
     89        return []
     90    return (
     91        value if isinstance(value, Collection) and not isinstance(value, (str, bytes)) else [value]
     92    )
     93
     94
     95def csv(*args: str, sep: str = ", ") -> str:
     96    """
     97    Formats any number of string arguments as CSV.
     98
     99    Args:
    100        args: the string arguments to format.
    101        sep: the argument separator.
    102
    103    Returns:
    104        The arguments formatted as a CSV string.
    105    """
    106    return sep.join(arg for arg in args if arg)
    107
    108
    109def subclasses(
    110    module_name: str,
    111    classes: t.Type | t.Tuple[t.Type, ...],
    112    exclude: t.Type | t.Tuple[t.Type, ...] = (),
    113) -> t.List[t.Type]:
    114    """
    115    Returns all subclasses for a collection of classes, possibly excluding some of them.
    116
    117    Args:
    118        module_name: the name of the module to search for subclasses in.
    119        classes: class(es) we want to find the subclasses of.
    120        exclude: class(es) we want to exclude from the returned list.
    121
    122    Returns:
    123        The target subclasses.
    124    """
    125    return [
    126        obj
    127        for _, obj in inspect.getmembers(
    128            sys.modules[module_name],
    129            lambda obj: inspect.isclass(obj) and issubclass(obj, classes) and obj not in exclude,
    130        )
    131    ]
    132
    133
    134def apply_index_offset(
    135    this: exp.Expression,
    136    expressions: t.List[t.Optional[E]],
    137    offset: int,
    138) -> t.List[t.Optional[E]]:
    139    """
    140    Applies an offset to a given integer literal expression.
    141
    142    Args:
    143        this: the target of the index
    144        expressions: the expression the offset will be applied to, wrapped in a list.
    145        offset: the offset that will be applied.
    146
    147    Returns:
    148        The original expression with the offset applied to it, wrapped in a list. If the provided
    149        `expressions` argument contains more than one expressions, it's returned unaffected.
    150    """
    151    if not offset or len(expressions) != 1:
    152        return expressions
    153
    154    expression = expressions[0]
    155
    156    from sqlglot import exp
    157    from sqlglot.optimizer.annotate_types import annotate_types
    158    from sqlglot.optimizer.simplify import simplify
    159
    160    if not this.type:
    161        annotate_types(this)
    162
    163    if t.cast(exp.DataType, this.type).this not in (
    164        exp.DataType.Type.UNKNOWN,
    165        exp.DataType.Type.ARRAY,
    166    ):
    167        return expressions
    168
    169    if expression:
    170        if not expression.type:
    171            annotate_types(expression)
    172        if t.cast(exp.DataType, expression.type).this in exp.DataType.INTEGER_TYPES:
    173            logger.warning("Applying array index offset (%s)", offset)
    174            expression = simplify(
    175                exp.Add(this=expression.copy(), expression=exp.Literal.number(offset))
    176            )
    177            return [expression]
    178
    179    return expressions
    180
    181
    182def camel_to_snake_case(name: str) -> str:
    183    """Converts `name` from camelCase to snake_case and returns the result."""
    184    return CAMEL_CASE_PATTERN.sub("_", name).upper()
    185
    186
    187def while_changing(expression: Expression, func: t.Callable[[Expression], E]) -> E:
    188    """
    189    Applies a transformation to a given expression until a fix point is reached.
    190
    191    Args:
    192        expression: the expression to be transformed.
    193        func: the transformation to be applied.
    194
    195    Returns:
    196        The transformed expression.
    197    """
    198    while True:
    199        for n, *_ in reversed(tuple(expression.walk())):
    200            n._hash = hash(n)
    201        start = hash(expression)
    202        expression = func(expression)
    203
    204        for n, *_ in expression.walk():
    205            n._hash = None
    206        if start == hash(expression):
    207            break
    208    return expression
    209
    210
    211def tsort(dag: t.Dict[T, t.List[T]]) -> t.List[T]:
    212    """
    213    Sorts a given directed acyclic graph in topological order.
    214
    215    Args:
    216        dag: the graph to be sorted.
    217
    218    Returns:
    219        A list that contains all of the graph's nodes in topological order.
    220    """
    221    result = []
    222
    223    def visit(node: T, visited: t.Set[T]) -> None:
    224        if node in result:
    225            return
    226        if node in visited:
    227            raise ValueError("Cycle error")
    228
    229        visited.add(node)
    230
    231        for dep in dag.get(node, []):
    232            visit(dep, visited)
    233
    234        visited.remove(node)
    235        result.append(node)
    236
    237    for node in dag:
    238        visit(node, set())
    239
    240    return result
    241
    242
    243def open_file(file_name: str) -> t.TextIO:
    244    """Open a file that may be compressed as gzip and return it in universal newline mode."""
    245    with open(file_name, "rb") as f:
    246        gzipped = f.read(2) == b"\x1f\x8b"
    247
    248    if gzipped:
    249        import gzip
    250
    251        return gzip.open(file_name, "rt", newline="")
    252
    253    return open(file_name, encoding="utf-8", newline="")
    254
    255
    256@contextmanager
    257def csv_reader(read_csv: exp.ReadCSV) -> t.Any:
    258    """
    259    Returns a csv reader given the expression `READ_CSV(name, ['delimiter', '|', ...])`.
    260
    261    Args:
    262        read_csv: a `ReadCSV` function call
    263
    264    Yields:
    265        A python csv reader.
    266    """
    267    args = read_csv.expressions
    268    file = open_file(read_csv.name)
    269
    270    delimiter = ","
    271    args = iter(arg.name for arg in args)
    272    for k, v in zip(args, args):
    273        if k == "delimiter":
    274            delimiter = v
    275
    276    try:
    277        import csv as csv_
    278
    279        yield csv_.reader(file, delimiter=delimiter)
    280    finally:
    281        file.close()
    282
    283
    284def find_new_name(taken: t.Collection[str], base: str) -> str:
    285    """
    286    Searches for a new name.
    287
    288    Args:
    289        taken: a collection of taken names.
    290        base: base name to alter.
    291
    292    Returns:
    293        The new, available name.
    294    """
    295    if base not in taken:
    296        return base
    297
    298    i = 2
    299    new = f"{base}_{i}"
    300    while new in taken:
    301        i += 1
    302        new = f"{base}_{i}"
    303
    304    return new
    305
    306
    307def name_sequence(prefix: str) -> t.Callable[[], str]:
    308    """Returns a name generator given a prefix (e.g. a0, a1, a2, ... if the prefix is "a")."""
    309    sequence = count()
    310    return lambda: f"{prefix}{next(sequence)}"
    311
    312
    313def object_to_dict(obj: t.Any, **kwargs) -> t.Dict:
    314    """Returns a dictionary created from an object's attributes."""
    315    return {
    316        **{k: v.copy() if hasattr(v, "copy") else copy(v) for k, v in vars(obj).items()},
    317        **kwargs,
    318    }
    319
    320
    321def split_num_words(
    322    value: str, sep: str, min_num_words: int, fill_from_start: bool = True
    323) -> t.List[t.Optional[str]]:
    324    """
    325    Perform a split on a value and return N words as a result with `None` used for words that don't exist.
    326
    327    Args:
    328        value: the value to be split.
    329        sep: the value to use to split on.
    330        min_num_words: the minimum number of words that are going to be in the result.
    331        fill_from_start: indicates that if `None` values should be inserted at the start or end of the list.
    332
    333    Examples:
    334        >>> split_num_words("db.table", ".", 3)
    335        [None, 'db', 'table']
    336        >>> split_num_words("db.table", ".", 3, fill_from_start=False)
    337        ['db', 'table', None]
    338        >>> split_num_words("db.table", ".", 1)
    339        ['db', 'table']
    340
    341    Returns:
    342        The list of words returned by `split`, possibly augmented by a number of `None` values.
    343    """
    344    words = value.split(sep)
    345    if fill_from_start:
    346        return [None] * (min_num_words - len(words)) + words
    347    return words + [None] * (min_num_words - len(words))
    348
    349
    350def is_iterable(value: t.Any) -> bool:
    351    """
    352    Checks if the value is an iterable, excluding the types `str` and `bytes`.
    353
    354    Examples:
    355        >>> is_iterable([1,2])
    356        True
    357        >>> is_iterable("test")
    358        False
    359
    360    Args:
    361        value: the value to check if it is an iterable.
    362
    363    Returns:
    364        A `bool` value indicating if it is an iterable.
    365    """
    366    return hasattr(value, "__iter__") and not isinstance(value, (str, bytes))
    367
    368
    369def flatten(values: t.Iterable[t.Iterable[t.Any] | t.Any]) -> t.Iterator[t.Any]:
    370    """
    371    Flattens an iterable that can contain both iterable and non-iterable elements. Objects of
    372    type `str` and `bytes` are not regarded as iterables.
    373
    374    Examples:
    375        >>> list(flatten([[1, 2], 3, {4}, (5, "bla")]))
    376        [1, 2, 3, 4, 5, 'bla']
    377        >>> list(flatten([1, 2, 3]))
    378        [1, 2, 3]
    379
    380    Args:
    381        values: the value to be flattened.
    382
    383    Yields:
    384        Non-iterable elements in `values`.
    385    """
    386    for value in values:
    387        if is_iterable(value):
    388            yield from flatten(value)
    389        else:
    390            yield value
    391
    392
    393def dict_depth(d: t.Dict) -> int:
    394    """
    395    Get the nesting depth of a dictionary.
    396
    397    For example:
    398        >>> dict_depth(None)
    399        0
    400        >>> dict_depth({})
    401        1
    402        >>> dict_depth({"a": "b"})
    403        1
    404        >>> dict_depth({"a": {}})
    405        2
    406        >>> dict_depth({"a": {"b": {}}})
    407        3
    408
    409    Args:
    410        d (dict): dictionary
    411
    412    Returns:
    413        int: depth
    414    """
    415    try:
    416        return 1 + dict_depth(next(iter(d.values())))
    417    except AttributeError:
    418        # d doesn't have attribute "values"
    419        return 0
    420    except StopIteration:
    421        # d.values() returns an empty sequence
    422        return 1
    423
    424
    425def first(it: t.Iterable[T]) -> T:
    426    """Returns the first element from an iterable.
    427
    428    Useful for sets.
    429    """
    430    return next(i for i in it)
    431
    432
    433def case_sensitive(text: str, dialect: DialectType) -> bool:
    434    """Checks if text contains any case sensitive characters depending on dialect."""
    435    from sqlglot.dialects.dialect import RESOLVES_IDENTIFIERS_AS_UPPERCASE
    436
    437    unsafe = str.islower if dialect in RESOLVES_IDENTIFIERS_AS_UPPERCASE else str.isupper
    438    return any(unsafe(char) for char in text)
    439
    440
    441def should_identify(text: str, identify: str | bool, dialect: DialectType = None) -> bool:
    442    """Checks if text should be identified given an identify option.
    443
    444    Args:
    445        text: the text to check.
    446        identify:
    447            "always" or `True`: always returns true.
    448            "safe": true if there is no uppercase or lowercase character in `text`, depending on `dialect`.
    449        dialect: the dialect to use in order to decide whether a text should be identified.
    450
    451    Returns:
    452        Whether or not a string should be identified.
    453    """
    454    if identify is True or identify == "always":
    455        return True
    456    if identify == "safe":
    457        return not case_sensitive(text, dialect)
    458    return False

class AutoName(enum.Enum): View Source

    26class AutoName(Enum):
    27    """This is used for creating enum classes where `auto()` is the string form of the corresponding value's name."""
    28
    29    def _generate_next_value_(name, _start, _count, _last_values):
    30        return name

This is used for creating enum classes where `auto()` is the string form of the corresponding value's name.

##### Inherited Members

enum.Enum
  name
  value

def seq_get(seq: Sequence[~T], index: int) -> Optional[~T]: View Source

    33def seq_get(seq: t.Sequence[T], index: int) -> t.Optional[T]:
    34    """Returns the value in `seq` at position `index`, or `None` if `index` is out of bounds."""
    35    try:
    36        return seq[index]
    37    except IndexError:
    38        return None

Returns the value in `seq` at position `index`, or `None` if `index` is out of bounds.

def ensure_list(value): View Source

    51def ensure_list(value):
    52    """
    53    Ensures that a value is a list, otherwise casts or wraps it into one.
    54
    55    Args:
    56        value: the value of interest.
    57
    58    Returns:
    59        The value cast as a list if it's a list or a tuple, or else the value wrapped in a list.
    60    """
    61    if value is None:
    62        return []
    63    if isinstance(value, (list, tuple)):
    64        return list(value)
    65
    66    return [value]

Ensures that a value is a list, otherwise casts or wraps it into one.

###### Arguments:

- value: the value of interest.

###### Returns:

> The value cast as a list if it's a list or a tuple, or else the value wrapped in a list.

def ensure_collection(value): View Source

    79def ensure_collection(value):
    80    """
    81    Ensures that a value is a collection (excluding `str` and `bytes`), otherwise wraps it into a list.
    82
    83    Args:
    84        value: the value of interest.
    85
    86    Returns:
    87        The value if it's a collection, or else the value wrapped in a list.
    88    """
    89    if value is None:
    90        return []
    91    return (
    92        value if isinstance(value, Collection) and not isinstance(value, (str, bytes)) else [value]
    93    )

Ensures that a value is a collection (excluding `str` and `bytes`), otherwise wraps it into a list.

###### Arguments:

- value: the value of interest.

###### Returns:

> The value if it's a collection, or else the value wrapped in a list.

def csv(*args: str, sep: str = ', ') -> str: View Source

     96def csv(*args: str, sep: str = ", ") -> str:
     97    """
     98    Formats any number of string arguments as CSV.
     99
    100    Args:
    101        args: the string arguments to format.
    102        sep: the argument separator.
    103
    104    Returns:
    105        The arguments formatted as a CSV string.
    106    """
    107    return sep.join(arg for arg in args if arg)

Formats any number of string arguments as CSV.

###### Arguments:

- args: the string arguments to format.
- sep: the argument separator.

###### Returns:

> The arguments formatted as a CSV string.

def subclasses( module_name: str, classes: Union[Type, Tuple[Type, ...]], exclude: Union[Type, Tuple[Type, ...]] = ()) -> List[Type]: View Source

    110def subclasses(
    111    module_name: str,
    112    classes: t.Type | t.Tuple[t.Type, ...],
    113    exclude: t.Type | t.Tuple[t.Type, ...] = (),
    114) -> t.List[t.Type]:
    115    """
    116    Returns all subclasses for a collection of classes, possibly excluding some of them.
    117
    118    Args:
    119        module_name: the name of the module to search for subclasses in.
    120        classes: class(es) we want to find the subclasses of.
    121        exclude: class(es) we want to exclude from the returned list.
    122
    123    Returns:
    124        The target subclasses.
    125    """
    126    return [
    127        obj
    128        for _, obj in inspect.getmembers(
    129            sys.modules[module_name],
    130            lambda obj: inspect.isclass(obj) and issubclass(obj, classes) and obj not in exclude,
    131        )
    132    ]

Returns all subclasses for a collection of classes, possibly excluding some of them.

###### Arguments:

- module_name: the name of the module to search for subclasses in.
- classes: class(es) we want to find the subclasses of.
- exclude: class(es) we want to exclude from the returned list.

###### Returns:

> The target subclasses.

def apply_index_offset( this: sqlglot.expressions.Expression, expressions: List[Optional[~E]], offset: int) -> List[Optional[~E]]: View Source

    135def apply_index_offset(
    136    this: exp.Expression,
    137    expressions: t.List[t.Optional[E]],
    138    offset: int,
    139) -> t.List[t.Optional[E]]:
    140    """
    141    Applies an offset to a given integer literal expression.
    142
    143    Args:
    144        this: the target of the index
    145        expressions: the expression the offset will be applied to, wrapped in a list.
    146        offset: the offset that will be applied.
    147
    148    Returns:
    149        The original expression with the offset applied to it, wrapped in a list. If the provided
    150        `expressions` argument contains more than one expressions, it's returned unaffected.
    151    """
    152    if not offset or len(expressions) != 1:
    153        return expressions
    154
    155    expression = expressions[0]
    156
    157    from sqlglot import exp
    158    from sqlglot.optimizer.annotate_types import annotate_types
    159    from sqlglot.optimizer.simplify import simplify
    160
    161    if not this.type:
    162        annotate_types(this)
    163
    164    if t.cast(exp.DataType, this.type).this not in (
    165        exp.DataType.Type.UNKNOWN,
    166        exp.DataType.Type.ARRAY,
    167    ):
    168        return expressions
    169
    170    if expression:
    171        if not expression.type:
    172            annotate_types(expression)
    173        if t.cast(exp.DataType, expression.type).this in exp.DataType.INTEGER_TYPES:
    174            logger.warning("Applying array index offset (%s)", offset)
    175            expression = simplify(
    176                exp.Add(this=expression.copy(), expression=exp.Literal.number(offset))
    177            )
    178            return [expression]
    179
    180    return expressions

Applies an offset to a given integer literal expression.

###### Arguments:

- this: the target of the index
- expressions: the expression the offset will be applied to, wrapped in a list.
- offset: the offset that will be applied.

###### Returns:

> The original expression with the offset applied to it, wrapped in a list. If the provided `expressions` argument contains more than one expressions, it's returned unaffected.

def camel_to_snake_case(name: str) -> str: View Source

    183def camel_to_snake_case(name: str) -> str:
    184    """Converts `name` from camelCase to snake_case and returns the result."""
    185    return CAMEL_CASE_PATTERN.sub("_", name).upper()

Converts `name` from camelCase to snake_case and returns the result.

def while_changing( expression: sqlglot.expressions.Expression, func: Callable[[sqlglot.expressions.Expression], ~E]) -> ~E: View Source

    188def while_changing(expression: Expression, func: t.Callable[[Expression], E]) -> E:
    189    """
    190    Applies a transformation to a given expression until a fix point is reached.
    191
    192    Args:
    193        expression: the expression to be transformed.
    194        func: the transformation to be applied.
    195
    196    Returns:
    197        The transformed expression.
    198    """
    199    while True:
    200        for n, *_ in reversed(tuple(expression.walk())):
    201            n._hash = hash(n)
    202        start = hash(expression)
    203        expression = func(expression)
    204
    205        for n, *_ in expression.walk():
    206            n._hash = None
    207        if start == hash(expression):
    208            break
    209    return expression

Applies a transformation to a given expression until a fix point is reached.

###### Arguments:

- expression: the expression to be transformed.
- func: the transformation to be applied.

###### Returns:

> The transformed expression.

def tsort(dag: Dict[~T, List[~T]]) -> List[~T]: View Source

    212def tsort(dag: t.Dict[T, t.List[T]]) -> t.List[T]:
    213    """
    214    Sorts a given directed acyclic graph in topological order.
    215
    216    Args:
    217        dag: the graph to be sorted.
    218
    219    Returns:
    220        A list that contains all of the graph's nodes in topological order.
    221    """
    222    result = []
    223
    224    def visit(node: T, visited: t.Set[T]) -> None:
    225        if node in result:
    226            return
    227        if node in visited:
    228            raise ValueError("Cycle error")
    229
    230        visited.add(node)
    231
    232        for dep in dag.get(node, []):
    233            visit(dep, visited)
    234
    235        visited.remove(node)
    236        result.append(node)
    237
    238    for node in dag:
    239        visit(node, set())
    240
    241    return result

Sorts a given directed acyclic graph in topological order.

###### Arguments:

- dag: the graph to be sorted.

###### Returns:

> A list that contains all of the graph's nodes in topological order.

def open_file(file_name: str) -> <class 'TextIO'>: View Source

    244def open_file(file_name: str) -> t.TextIO:
    245    """Open a file that may be compressed as gzip and return it in universal newline mode."""
    246    with open(file_name, "rb") as f:
    247        gzipped = f.read(2) == b"\x1f\x8b"
    248
    249    if gzipped:
    250        import gzip
    251
    252        return gzip.open(file_name, "rt", newline="")
    253
    254    return open(file_name, encoding="utf-8", newline="")

Open a file that may be compressed as gzip and return it in universal newline mode.

@contextmanager
def csv_reader(read_csv: sqlglot.expressions.ReadCSV) -> Any: View Source

    257@contextmanager
    258def csv_reader(read_csv: exp.ReadCSV) -> t.Any:
    259    """
    260    Returns a csv reader given the expression `READ_CSV(name, ['delimiter', '|', ...])`.
    261
    262    Args:
    263        read_csv: a `ReadCSV` function call
    264
    265    Yields:
    266        A python csv reader.
    267    """
    268    args = read_csv.expressions
    269    file = open_file(read_csv.name)
    270
    271    delimiter = ","
    272    args = iter(arg.name for arg in args)
    273    for k, v in zip(args, args):
    274        if k == "delimiter":
    275            delimiter = v
    276
    277    try:
    278        import csv as csv_
    279
    280        yield csv_.reader(file, delimiter=delimiter)
    281    finally:
    282        file.close()

Returns a csv reader given the expression `READ_CSV(name, ['delimiter', '|', ...])`.

###### Arguments:

- read_csv: a `ReadCSV` function call

###### Yields:

> A python csv reader.

def find_new_name(taken: Collection[str], base: str) -> str: View Source

    285def find_new_name(taken: t.Collection[str], base: str) -> str:
    286    """
    287    Searches for a new name.
    288
    289    Args:
    290        taken: a collection of taken names.
    291        base: base name to alter.
    292
    293    Returns:
    294        The new, available name.
    295    """
    296    if base not in taken:
    297        return base
    298
    299    i = 2
    300    new = f"{base}_{i}"
    301    while new in taken:
    302        i += 1
    303        new = f"{base}_{i}"
    304
    305    return new

Searches for a new name.

###### Arguments:

- taken: a collection of taken names.
- base: base name to alter.

###### Returns:

> The new, available name.

def name_sequence(prefix: str) -> Callable[[], str]: View Source

    308def name_sequence(prefix: str) -> t.Callable[[], str]:
    309    """Returns a name generator given a prefix (e.g. a0, a1, a2, ... if the prefix is "a")."""
    310    sequence = count()
    311    return lambda: f"{prefix}{next(sequence)}"

Returns a name generator given a prefix (e.g. a0, a1, a2, ... if the prefix is "a").

def object_to_dict(obj: Any, **kwargs) -> Dict: View Source

    314def object_to_dict(obj: t.Any, **kwargs) -> t.Dict:
    315    """Returns a dictionary created from an object's attributes."""
    316    return {
    317        **{k: v.copy() if hasattr(v, "copy") else copy(v) for k, v in vars(obj).items()},
    318        **kwargs,
    319    }

Returns a dictionary created from an object's attributes.

def split_num_words( value: str, sep: str, min_num_words: int, fill_from_start: bool = True) -> List[Optional[str]]: View Source

    322def split_num_words(
    323    value: str, sep: str, min_num_words: int, fill_from_start: bool = True
    324) -> t.List[t.Optional[str]]:
    325    """
    326    Perform a split on a value and return N words as a result with `None` used for words that don't exist.
    327
    328    Args:
    329        value: the value to be split.
    330        sep: the value to use to split on.
    331        min_num_words: the minimum number of words that are going to be in the result.
    332        fill_from_start: indicates that if `None` values should be inserted at the start or end of the list.
    333
    334    Examples:
    335        >>> split_num_words("db.table", ".", 3)
    336        [None, 'db', 'table']
    337        >>> split_num_words("db.table", ".", 3, fill_from_start=False)
    338        ['db', 'table', None]
    339        >>> split_num_words("db.table", ".", 1)
    340        ['db', 'table']
    341
    342    Returns:
    343        The list of words returned by `split`, possibly augmented by a number of `None` values.
    344    """
    345    words = value.split(sep)
    346    if fill_from_start:
    347        return [None] * (min_num_words - len(words)) + words
    348    return words + [None] * (min_num_words - len(words))

Perform a split on a value and return N words as a result with `None` used for words that don't exist.

###### Arguments:

- value: the value to be split.
- sep: the value to use to split on.
- min_num_words: the minimum number of words that are going to be in the result.
- fill_from_start: indicates that if `None` values should be inserted at the start or end of the list.

###### Examples:

>     >>> split_num_words("db.table", ".", 3)
>     [None, 'db', 'table']
>     >>> split_num_words("db.table", ".", 3, fill_from_start=False)
>     ['db', 'table', None]
>     >>> split_num_words("db.table", ".", 1)
>     ['db', 'table']

###### Returns:

> The list of words returned by `split`, possibly augmented by a number of `None` values.

def is_iterable(value: Any) -> bool: View Source

    351def is_iterable(value: t.Any) -> bool:
    352    """
    353    Checks if the value is an iterable, excluding the types `str` and `bytes`.
    354
    355    Examples:
    356        >>> is_iterable([1,2])
    357        True
    358        >>> is_iterable("test")
    359        False
    360
    361    Args:
    362        value: the value to check if it is an iterable.
    363
    364    Returns:
    365        A `bool` value indicating if it is an iterable.
    366    """
    367    return hasattr(value, "__iter__") and not isinstance(value, (str, bytes))

Checks if the value is an iterable, excluding the types `str` and `bytes`.

###### Examples:

>     >>> is_iterable([1,2])
>     True
>     >>> is_iterable("test")
>     False

###### Arguments:

- value: the value to check if it is an iterable.

###### Returns:

> A `bool` value indicating if it is an iterable.

def flatten(values: Iterable[Union[Iterable[Any], Any]]) -> Iterator[Any]: View Source

    370def flatten(values: t.Iterable[t.Iterable[t.Any] | t.Any]) -> t.Iterator[t.Any]:
    371    """
    372    Flattens an iterable that can contain both iterable and non-iterable elements. Objects of
    373    type `str` and `bytes` are not regarded as iterables.
    374
    375    Examples:
    376        >>> list(flatten([[1, 2], 3, {4}, (5, "bla")]))
    377        [1, 2, 3, 4, 5, 'bla']
    378        >>> list(flatten([1, 2, 3]))
    379        [1, 2, 3]
    380
    381    Args:
    382        values: the value to be flattened.
    383
    384    Yields:
    385        Non-iterable elements in `values`.
    386    """
    387    for value in values:
    388        if is_iterable(value):
    389            yield from flatten(value)
    390        else:
    391            yield value

Flattens an iterable that can contain both iterable and non-iterable elements. Objects of type `str` and `bytes` are not regarded as iterables.

###### Examples:

>     >>> list(flatten([[1, 2], 3, {4}, (5, "bla")]))
>     [1, 2, 3, 4, 5, 'bla']
>     >>> list(flatten([1, 2, 3]))
>     [1, 2, 3]

###### Arguments:

- values: the value to be flattened.

###### Yields:

> Non-iterable elements in `values`.

def dict_depth(d: Dict) -> int: View Source

    394def dict_depth(d: t.Dict) -> int:
    395    """
    396    Get the nesting depth of a dictionary.
    397
    398    For example:
    399        >>> dict_depth(None)
    400        0
    401        >>> dict_depth({})
    402        1
    403        >>> dict_depth({"a": "b"})
    404        1
    405        >>> dict_depth({"a": {}})
    406        2
    407        >>> dict_depth({"a": {"b": {}}})
    408        3
    409
    410    Args:
    411        d (dict): dictionary
    412
    413    Returns:
    414        int: depth
    415    """
    416    try:
    417        return 1 + dict_depth(next(iter(d.values())))
    418    except AttributeError:
    419        # d doesn't have attribute "values"
    420        return 0
    421    except StopIteration:
    422        # d.values() returns an empty sequence
    423        return 1

Get the nesting depth of a dictionary.

###### For example:

>     >>> dict_depth(None)
>     0
>     >>> dict_depth({})
>     1
>     >>> dict_depth({"a": "b"})
>     1
>     >>> dict_depth({"a": {}})
>     2
>     >>> dict_depth({"a": {"b": {}}})
>     3

###### Arguments:

- d (dict): dictionary

###### Returns:

> int: depth

def first(it: Iterable[~T]) -> ~T: View Source

    426def first(it: t.Iterable[T]) -> T:
    427    """Returns the first element from an iterable.
    428
    429    Useful for sets.
    430    """
    431    return next(i for i in it)

Returns the first element from an iterable.

Useful for sets.

def case_sensitive( text: str, dialect: Union[str, sqlglot.dialects.dialect.Dialect, Type[sqlglot.dialects.dialect.Dialect], NoneType]) -> bool: View Source

    434def case_sensitive(text: str, dialect: DialectType) -> bool:
    435    """Checks if text contains any case sensitive characters depending on dialect."""
    436    from sqlglot.dialects.dialect import RESOLVES_IDENTIFIERS_AS_UPPERCASE
    437
    438    unsafe = str.islower if dialect in RESOLVES_IDENTIFIERS_AS_UPPERCASE else str.isupper
    439    return any(unsafe(char) for char in text)

Checks if text contains any case sensitive characters depending on dialect.

def should_identify( text: str, identify: str | bool, dialect: Union[str, sqlglot.dialects.dialect.Dialect, Type[sqlglot.dialects.dialect.Dialect], NoneType] = None) -> bool: View Source

    442def should_identify(text: str, identify: str | bool, dialect: DialectType = None) -> bool:
    443    """Checks if text should be identified given an identify option.
    444
    445    Args:
    446        text: the text to check.
    447        identify:
    448            "always" or `True`: always returns true.
    449            "safe": true if there is no uppercase or lowercase character in `text`, depending on `dialect`.
    450        dialect: the dialect to use in order to decide whether a text should be identified.
    451
    452    Returns:
    453        Whether or not a string should be identified.
    454    """
    455    if identify is True or identify == "always":
    456        return True
    457    if identify == "safe":
    458        return not case_sensitive(text, dialect)
    459    return False

Checks if text should be identified given an identify option.

###### Arguments:

- text: the text to check.
- identify: "always" or `True`: always returns true. "safe": true if there is no uppercase or lowercase character in `text`, depending on `dialect`.
- dialect: the dialect to use in order to decide whether a text should be identified.

###### Returns:

> Whether or not a string should be identified.