205 lines
6.5 KiB
Python
205 lines
6.5 KiB
Python
import datetime
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import inspect
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import re
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import statistics
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from functools import wraps
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from sqlglot import exp
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from sqlglot.generator import Generator
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from sqlglot.helper import PYTHON_VERSION
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class reverse_key:
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def __init__(self, obj):
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self.obj = obj
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def __eq__(self, other):
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return other.obj == self.obj
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def __lt__(self, other):
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return other.obj < self.obj
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def filter_nulls(func, empty_null=True):
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@wraps(func)
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def _func(values):
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filtered = tuple(v for v in values if v is not None)
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if not filtered and empty_null:
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return None
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return func(filtered)
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return _func
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def null_if_any(*required):
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"""
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Decorator that makes a function return `None` if any of the `required` arguments are `None`.
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This also supports decoration with no arguments, e.g.:
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@null_if_any
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def foo(a, b): ...
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In which case all arguments are required.
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"""
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f = None
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if len(required) == 1 and callable(required[0]):
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f = required[0]
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required = ()
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def decorator(func):
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if required:
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required_indices = [
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i for i, param in enumerate(inspect.signature(func).parameters) if param in required
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]
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def predicate(*args):
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return any(args[i] is None for i in required_indices)
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else:
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def predicate(*args):
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return any(a is None for a in args)
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@wraps(func)
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def _func(*args):
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if predicate(*args):
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return None
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return func(*args)
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return _func
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if f:
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return decorator(f)
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return decorator
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@null_if_any("substr", "this")
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def str_position(substr, this, position=None):
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position = position - 1 if position is not None else position
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return this.find(substr, position) + 1
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@null_if_any("this")
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def substring(this, start=None, length=None):
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if start is None:
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return this
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elif start == 0:
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return ""
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elif start < 0:
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start = len(this) + start
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else:
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start -= 1
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end = None if length is None else start + length
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return this[start:end]
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@null_if_any
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def cast(this, to):
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if to == exp.DataType.Type.DATE:
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if isinstance(this, datetime.datetime):
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return this.date()
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if isinstance(this, datetime.date):
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return this
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if isinstance(this, str):
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return datetime.date.fromisoformat(this)
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if to in (exp.DataType.Type.DATETIME, exp.DataType.Type.TIMESTAMP):
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if isinstance(this, datetime.datetime):
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return this
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if isinstance(this, datetime.date):
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return datetime.datetime(this.year, this.month, this.day)
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if isinstance(this, str):
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return datetime.datetime.fromisoformat(this)
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if to == exp.DataType.Type.BOOLEAN:
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return bool(this)
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if to in exp.DataType.TEXT_TYPES:
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return str(this)
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if to in {exp.DataType.Type.FLOAT, exp.DataType.Type.DOUBLE}:
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return float(this)
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if to in exp.DataType.NUMERIC_TYPES:
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return int(this)
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raise NotImplementedError(f"Casting {this} to '{to}' not implemented.")
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def ordered(this, desc, nulls_first):
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if desc:
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return reverse_key(this)
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return this
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@null_if_any
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def interval(this, unit):
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unit = unit.lower()
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plural = unit + "s"
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if plural in Generator.TIME_PART_SINGULARS:
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unit = plural
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return datetime.timedelta(**{unit: float(this)})
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ENV = {
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"exp": exp,
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# aggs
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"ARRAYAGG": list,
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"AVG": filter_nulls(statistics.fmean if PYTHON_VERSION >= (3, 8) else statistics.mean), # type: ignore
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"COUNT": filter_nulls(lambda acc: sum(1 for _ in acc), False),
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"MAX": filter_nulls(max),
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"MIN": filter_nulls(min),
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"SUM": filter_nulls(sum),
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# scalar functions
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"ABS": null_if_any(lambda this: abs(this)),
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"ADD": null_if_any(lambda e, this: e + this),
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"ARRAYANY": null_if_any(lambda arr, func: any(func(e) for e in arr)),
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"BETWEEN": null_if_any(lambda this, low, high: low <= this and this <= high),
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"BITWISEAND": null_if_any(lambda this, e: this & e),
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"BITWISELEFTSHIFT": null_if_any(lambda this, e: this << e),
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"BITWISEOR": null_if_any(lambda this, e: this | e),
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"BITWISERIGHTSHIFT": null_if_any(lambda this, e: this >> e),
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"BITWISEXOR": null_if_any(lambda this, e: this ^ e),
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"CAST": cast,
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"COALESCE": lambda *args: next((a for a in args if a is not None), None),
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"CONCAT": null_if_any(lambda *args: "".join(args)),
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"SAFECONCAT": null_if_any(lambda *args: "".join(str(arg) for arg in args)),
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"CONCATWS": null_if_any(lambda this, *args: this.join(args)),
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"DATEDIFF": null_if_any(lambda this, expression, *_: (this - expression).days),
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"DATESTRTODATE": null_if_any(lambda arg: datetime.date.fromisoformat(arg)),
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"DIV": null_if_any(lambda e, this: e / this),
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"DOT": null_if_any(lambda e, this: e[this]),
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"EQ": null_if_any(lambda this, e: this == e),
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"EXTRACT": null_if_any(lambda this, e: getattr(e, this)),
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"GT": null_if_any(lambda this, e: this > e),
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"GTE": null_if_any(lambda this, e: this >= e),
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"IF": lambda predicate, true, false: true if predicate else false,
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"INTDIV": null_if_any(lambda e, this: e // this),
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"INTERVAL": interval,
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"LEFT": null_if_any(lambda this, e: this[:e]),
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"LIKE": null_if_any(
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lambda this, e: bool(re.match(e.replace("_", ".").replace("%", ".*"), this))
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),
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"LOWER": null_if_any(lambda arg: arg.lower()),
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"LT": null_if_any(lambda this, e: this < e),
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"LTE": null_if_any(lambda this, e: this <= e),
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"MAP": null_if_any(lambda *args: dict(zip(*args))), # type: ignore
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"MOD": null_if_any(lambda e, this: e % this),
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"MUL": null_if_any(lambda e, this: e * this),
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"NEQ": null_if_any(lambda this, e: this != e),
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"ORD": null_if_any(ord),
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"ORDERED": ordered,
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"POW": pow,
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"RIGHT": null_if_any(lambda this, e: this[-e:]),
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"STRPOSITION": str_position,
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"SUB": null_if_any(lambda e, this: e - this),
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"SUBSTRING": substring,
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"TIMESTRTOTIME": null_if_any(lambda arg: datetime.datetime.fromisoformat(arg)),
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"UPPER": null_if_any(lambda arg: arg.upper()),
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"YEAR": null_if_any(lambda arg: arg.year),
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"MONTH": null_if_any(lambda arg: arg.month),
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"DAY": null_if_any(lambda arg: arg.day),
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"CURRENTDATETIME": datetime.datetime.now,
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"CURRENTTIMESTAMP": datetime.datetime.now,
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"CURRENTTIME": datetime.datetime.now,
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"CURRENTDATE": datetime.date.today,
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"STRFTIME": null_if_any(lambda fmt, arg: datetime.datetime.fromisoformat(arg).strftime(fmt)),
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}
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