sqlglot.helper
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.Set[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 for node, deps in tuple(dag.items()): 224 for dep in deps: 225 if not dep in dag: 226 dag[dep] = set() 227 228 while dag: 229 current = {node for node, deps in dag.items() if not deps} 230 231 if not current: 232 raise ValueError("Cycle error") 233 234 for node in current: 235 dag.pop(node) 236 237 for deps in dag.values(): 238 deps -= current 239 240 result.extend(sorted(current)) # type: ignore 241 242 return result 243 244 245def open_file(file_name: str) -> t.TextIO: 246 """Open a file that may be compressed as gzip and return it in universal newline mode.""" 247 with open(file_name, "rb") as f: 248 gzipped = f.read(2) == b"\x1f\x8b" 249 250 if gzipped: 251 import gzip 252 253 return gzip.open(file_name, "rt", newline="") 254 255 return open(file_name, encoding="utf-8", newline="") 256 257 258@contextmanager 259def csv_reader(read_csv: exp.ReadCSV) -> t.Any: 260 """ 261 Returns a csv reader given the expression `READ_CSV(name, ['delimiter', '|', ...])`. 262 263 Args: 264 read_csv: a `ReadCSV` function call 265 266 Yields: 267 A python csv reader. 268 """ 269 args = read_csv.expressions 270 file = open_file(read_csv.name) 271 272 delimiter = "," 273 args = iter(arg.name for arg in args) 274 for k, v in zip(args, args): 275 if k == "delimiter": 276 delimiter = v 277 278 try: 279 import csv as csv_ 280 281 yield csv_.reader(file, delimiter=delimiter) 282 finally: 283 file.close() 284 285 286def find_new_name(taken: t.Collection[str], base: str) -> str: 287 """ 288 Searches for a new name. 289 290 Args: 291 taken: a collection of taken names. 292 base: base name to alter. 293 294 Returns: 295 The new, available name. 296 """ 297 if base not in taken: 298 return base 299 300 i = 2 301 new = f"{base}_{i}" 302 while new in taken: 303 i += 1 304 new = f"{base}_{i}" 305 306 return new 307 308 309def name_sequence(prefix: str) -> t.Callable[[], str]: 310 """Returns a name generator given a prefix (e.g. a0, a1, a2, ... if the prefix is "a").""" 311 sequence = count() 312 return lambda: f"{prefix}{next(sequence)}" 313 314 315def object_to_dict(obj: t.Any, **kwargs) -> t.Dict: 316 """Returns a dictionary created from an object's attributes.""" 317 return { 318 **{k: v.copy() if hasattr(v, "copy") else copy(v) for k, v in vars(obj).items()}, 319 **kwargs, 320 } 321 322 323def split_num_words( 324 value: str, sep: str, min_num_words: int, fill_from_start: bool = True 325) -> t.List[t.Optional[str]]: 326 """ 327 Perform a split on a value and return N words as a result with `None` used for words that don't exist. 328 329 Args: 330 value: the value to be split. 331 sep: the value to use to split on. 332 min_num_words: the minimum number of words that are going to be in the result. 333 fill_from_start: indicates that if `None` values should be inserted at the start or end of the list. 334 335 Examples: 336 >>> split_num_words("db.table", ".", 3) 337 [None, 'db', 'table'] 338 >>> split_num_words("db.table", ".", 3, fill_from_start=False) 339 ['db', 'table', None] 340 >>> split_num_words("db.table", ".", 1) 341 ['db', 'table'] 342 343 Returns: 344 The list of words returned by `split`, possibly augmented by a number of `None` values. 345 """ 346 words = value.split(sep) 347 if fill_from_start: 348 return [None] * (min_num_words - len(words)) + words 349 return words + [None] * (min_num_words - len(words)) 350 351 352def is_iterable(value: t.Any) -> bool: 353 """ 354 Checks if the value is an iterable, excluding the types `str` and `bytes`. 355 356 Examples: 357 >>> is_iterable([1,2]) 358 True 359 >>> is_iterable("test") 360 False 361 362 Args: 363 value: the value to check if it is an iterable. 364 365 Returns: 366 A `bool` value indicating if it is an iterable. 367 """ 368 return hasattr(value, "__iter__") and not isinstance(value, (str, bytes)) 369 370 371def flatten(values: t.Iterable[t.Iterable[t.Any] | t.Any]) -> t.Iterator[t.Any]: 372 """ 373 Flattens an iterable that can contain both iterable and non-iterable elements. Objects of 374 type `str` and `bytes` are not regarded as iterables. 375 376 Examples: 377 >>> list(flatten([[1, 2], 3, {4}, (5, "bla")])) 378 [1, 2, 3, 4, 5, 'bla'] 379 >>> list(flatten([1, 2, 3])) 380 [1, 2, 3] 381 382 Args: 383 values: the value to be flattened. 384 385 Yields: 386 Non-iterable elements in `values`. 387 """ 388 for value in values: 389 if is_iterable(value): 390 yield from flatten(value) 391 else: 392 yield value 393 394 395def dict_depth(d: t.Dict) -> int: 396 """ 397 Get the nesting depth of a dictionary. 398 399 For example: 400 >>> dict_depth(None) 401 0 402 >>> dict_depth({}) 403 1 404 >>> dict_depth({"a": "b"}) 405 1 406 >>> dict_depth({"a": {}}) 407 2 408 >>> dict_depth({"a": {"b": {}}}) 409 3 410 411 Args: 412 d (dict): dictionary 413 414 Returns: 415 int: depth 416 """ 417 try: 418 return 1 + dict_depth(next(iter(d.values()))) 419 except AttributeError: 420 # d doesn't have attribute "values" 421 return 0 422 except StopIteration: 423 # d.values() returns an empty sequence 424 return 1 425 426 427def first(it: t.Iterable[T]) -> T: 428 """Returns the first element from an iterable. 429 430 Useful for sets. 431 """ 432 return next(i for i in it) 433 434 435def case_sensitive(text: str, dialect: DialectType) -> bool: 436 """Checks if text contains any case sensitive characters depending on dialect.""" 437 from sqlglot.dialects.dialect import RESOLVES_IDENTIFIERS_AS_UPPERCASE 438 439 unsafe = str.islower if dialect in RESOLVES_IDENTIFIERS_AS_UPPERCASE else str.isupper 440 return any(unsafe(char) for char in text) 441 442 443def should_identify(text: str, identify: str | bool, dialect: DialectType = None) -> bool: 444 """Checks if text should be identified given an identify option. 445 446 Args: 447 text: the text to check. 448 identify: 449 "always" or `True`: always returns true. 450 "safe": true if there is no uppercase or lowercase character in `text`, depending on `dialect`. 451 dialect: the dialect to use in order to decide whether a text should be identified. 452 453 Returns: 454 Whether or not a string should be identified. 455 """ 456 if identify is True or identify == "always": 457 return True 458 if identify == "safe": 459 return not case_sensitive(text, dialect) 460 return False
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
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.
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.
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.
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.
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.
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.
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.
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.
212def tsort(dag: t.Dict[T, t.Set[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 for node, deps in tuple(dag.items()): 225 for dep in deps: 226 if not dep in dag: 227 dag[dep] = set() 228 229 while dag: 230 current = {node for node, deps in dag.items() if not deps} 231 232 if not current: 233 raise ValueError("Cycle error") 234 235 for node in current: 236 dag.pop(node) 237 238 for deps in dag.values(): 239 deps -= current 240 241 result.extend(sorted(current)) # type: ignore 242 243 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.
246def open_file(file_name: str) -> t.TextIO: 247 """Open a file that may be compressed as gzip and return it in universal newline mode.""" 248 with open(file_name, "rb") as f: 249 gzipped = f.read(2) == b"\x1f\x8b" 250 251 if gzipped: 252 import gzip 253 254 return gzip.open(file_name, "rt", newline="") 255 256 return open(file_name, encoding="utf-8", newline="")
Open a file that may be compressed as gzip and return it in universal newline mode.
259@contextmanager 260def csv_reader(read_csv: exp.ReadCSV) -> t.Any: 261 """ 262 Returns a csv reader given the expression `READ_CSV(name, ['delimiter', '|', ...])`. 263 264 Args: 265 read_csv: a `ReadCSV` function call 266 267 Yields: 268 A python csv reader. 269 """ 270 args = read_csv.expressions 271 file = open_file(read_csv.name) 272 273 delimiter = "," 274 args = iter(arg.name for arg in args) 275 for k, v in zip(args, args): 276 if k == "delimiter": 277 delimiter = v 278 279 try: 280 import csv as csv_ 281 282 yield csv_.reader(file, delimiter=delimiter) 283 finally: 284 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.
287def find_new_name(taken: t.Collection[str], base: str) -> str: 288 """ 289 Searches for a new name. 290 291 Args: 292 taken: a collection of taken names. 293 base: base name to alter. 294 295 Returns: 296 The new, available name. 297 """ 298 if base not in taken: 299 return base 300 301 i = 2 302 new = f"{base}_{i}" 303 while new in taken: 304 i += 1 305 new = f"{base}_{i}" 306 307 return new
Searches for a new name.
Arguments:
- taken: a collection of taken names.
- base: base name to alter.
Returns:
The new, available name.
310def name_sequence(prefix: str) -> t.Callable[[], str]: 311 """Returns a name generator given a prefix (e.g. a0, a1, a2, ... if the prefix is "a").""" 312 sequence = count() 313 return lambda: f"{prefix}{next(sequence)}"
Returns a name generator given a prefix (e.g. a0, a1, a2, ... if the prefix is "a").
316def object_to_dict(obj: t.Any, **kwargs) -> t.Dict: 317 """Returns a dictionary created from an object's attributes.""" 318 return { 319 **{k: v.copy() if hasattr(v, "copy") else copy(v) for k, v in vars(obj).items()}, 320 **kwargs, 321 }
Returns a dictionary created from an object's attributes.
324def split_num_words( 325 value: str, sep: str, min_num_words: int, fill_from_start: bool = True 326) -> t.List[t.Optional[str]]: 327 """ 328 Perform a split on a value and return N words as a result with `None` used for words that don't exist. 329 330 Args: 331 value: the value to be split. 332 sep: the value to use to split on. 333 min_num_words: the minimum number of words that are going to be in the result. 334 fill_from_start: indicates that if `None` values should be inserted at the start or end of the list. 335 336 Examples: 337 >>> split_num_words("db.table", ".", 3) 338 [None, 'db', 'table'] 339 >>> split_num_words("db.table", ".", 3, fill_from_start=False) 340 ['db', 'table', None] 341 >>> split_num_words("db.table", ".", 1) 342 ['db', 'table'] 343 344 Returns: 345 The list of words returned by `split`, possibly augmented by a number of `None` values. 346 """ 347 words = value.split(sep) 348 if fill_from_start: 349 return [None] * (min_num_words - len(words)) + words 350 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 ofNone
values.
353def is_iterable(value: t.Any) -> bool: 354 """ 355 Checks if the value is an iterable, excluding the types `str` and `bytes`. 356 357 Examples: 358 >>> is_iterable([1,2]) 359 True 360 >>> is_iterable("test") 361 False 362 363 Args: 364 value: the value to check if it is an iterable. 365 366 Returns: 367 A `bool` value indicating if it is an iterable. 368 """ 369 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.
372def flatten(values: t.Iterable[t.Iterable[t.Any] | t.Any]) -> t.Iterator[t.Any]: 373 """ 374 Flattens an iterable that can contain both iterable and non-iterable elements. Objects of 375 type `str` and `bytes` are not regarded as iterables. 376 377 Examples: 378 >>> list(flatten([[1, 2], 3, {4}, (5, "bla")])) 379 [1, 2, 3, 4, 5, 'bla'] 380 >>> list(flatten([1, 2, 3])) 381 [1, 2, 3] 382 383 Args: 384 values: the value to be flattened. 385 386 Yields: 387 Non-iterable elements in `values`. 388 """ 389 for value in values: 390 if is_iterable(value): 391 yield from flatten(value) 392 else: 393 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
.
396def dict_depth(d: t.Dict) -> int: 397 """ 398 Get the nesting depth of a dictionary. 399 400 For example: 401 >>> dict_depth(None) 402 0 403 >>> dict_depth({}) 404 1 405 >>> dict_depth({"a": "b"}) 406 1 407 >>> dict_depth({"a": {}}) 408 2 409 >>> dict_depth({"a": {"b": {}}}) 410 3 411 412 Args: 413 d (dict): dictionary 414 415 Returns: 416 int: depth 417 """ 418 try: 419 return 1 + dict_depth(next(iter(d.values()))) 420 except AttributeError: 421 # d doesn't have attribute "values" 422 return 0 423 except StopIteration: 424 # d.values() returns an empty sequence 425 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
428def first(it: t.Iterable[T]) -> T: 429 """Returns the first element from an iterable. 430 431 Useful for sets. 432 """ 433 return next(i for i in it)
Returns the first element from an iterable.
Useful for sets.
436def case_sensitive(text: str, dialect: DialectType) -> bool: 437 """Checks if text contains any case sensitive characters depending on dialect.""" 438 from sqlglot.dialects.dialect import RESOLVES_IDENTIFIERS_AS_UPPERCASE 439 440 unsafe = str.islower if dialect in RESOLVES_IDENTIFIERS_AS_UPPERCASE else str.isupper 441 return any(unsafe(char) for char in text)
Checks if text contains any case sensitive characters depending on dialect.
444def should_identify(text: str, identify: str | bool, dialect: DialectType = None) -> bool: 445 """Checks if text should be identified given an identify option. 446 447 Args: 448 text: the text to check. 449 identify: 450 "always" or `True`: always returns true. 451 "safe": true if there is no uppercase or lowercase character in `text`, depending on `dialect`. 452 dialect: the dialect to use in order to decide whether a text should be identified. 453 454 Returns: 455 Whether or not a string should be identified. 456 """ 457 if identify is True or identify == "always": 458 return True 459 if identify == "safe": 460 return not case_sensitive(text, dialect) 461 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 intext
, depending ondialect
. - dialect: the dialect to use in order to decide whether a text should be identified.
Returns:
Whether or not a string should be identified.