cast

Module nu.core.cast.

Cast atoms: Python's type constructors and conversions.

Maps Python's builtin type constructors onto Nu ScalarQueries that build a value of the target type from their argument. Pure compute; no Context effect of their own.

The split follows one rule - what the constructor consumes:

scalar casts take a scalar operand and compute a scalar, so they are pure ScalarQueries with compile / acompile thunks (sentinel-aware, like arithmetic): int -> ToInt, float -> ToFloat, complex -> ToComplex, str -> ToStr, bytes -> ToBytes, bytearray -> ToByteArray. ToInt, ToBytes and ToByteArray take an optional second operand (base / encoding) where Python does, branched on child count like arithmetic.Round.
collection constructors consume an iterable child and fold it to one container (Scalar over Stream, a Reduction in spirit), so they need the stream/fabric runtime that is not wired yet. They are declared structurally - ScalarQuery subclasses with no compile - and evaluate once the fabric lands: list -> ToList, tuple -> ToTuple, set -> ToSet, frozenset -> ToFrozenSet, dict -> ToDict.

Bool truthiness lives in logical; it is intentionally not defined here.

Name	Sort	Call	Meaning
ToByteArray	`scalar_query`	`ToByteArray(value, encoding)`	The operand cast to `bytearray`.
ToBytes	`scalar_query`	`ToBytes(value, encoding)`	The operand cast to `bytes`.
ToComplex	`scalar_query`	`ToComplex(real, imag)`	The operand cast to `complex`.
ToDict	`scalar_query`	`ToDict(value)`	The key/value pairs of the iterable child collected into a `dict`.
ToFloat	`scalar_query`	`ToFloat(value)`	The operand cast to `float`.
ToFrozenSet	`scalar_query`	`ToFrozenSet(value)`	The iterable child collected into a `frozenset`.
ToInt	`scalar_query`	`ToInt(value, base)`	The operand cast to `int`.
ToList	`scalar_query`	`ToList(value)`	The iterable child collected into a `list`.
ToSet	`scalar_query`	`ToSet(value)`	The iterable child collected into a `set`.
ToStr	`scalar_query`	`ToStr(value)`	The operand cast to `str`.
ToTuple	`scalar_query`	`ToTuple(value)`	The iterable child collected into a `tuple`.

ToByteArray

The operand cast to bytearray.

ToByteArray(value, encoding)

Path nu.core.ToByteArray. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 2 (2 required).

Arguments

Name	Type	Default	Meaning
`value`			the value to convert.
`encoding`			optional. When given, `value` must be a string and is encoded with it. Without it, follows single-argument `bytearray()`: an int yields that many zero bytes, an iterable of ints yields those bytes.

Yields

The bytearray. INVALID when either child is EMPTY or INVALID.

Example

nu.run(nu.ToByteArray("hi", "utf-8"))[0]

bytearray(b'hi')

ToBytes

The operand cast to bytes.

ToBytes(value, encoding)

Path nu.core.ToBytes. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 2 (2 required).

Arguments

Name	Type	Default	Meaning
`value`			the value to convert.
`encoding`			optional. When given, `value` must be a string and is encoded with it. Without it, follows single-argument `bytes()`: an int yields that many zero bytes, an iterable of ints yields those bytes.

Yields

The bytes. INVALID when either child is EMPTY or INVALID.

Example

nu.run(nu.ToBytes("hi", "utf-8"))[0]

b'hi'

ToComplex

The operand cast to complex.

ToComplex(real, imag)

Path nu.core.ToComplex. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 2 (2 required).

Arguments

Name	Type	Default	Meaning
`real`			the value to convert, or the real part when `imag` is given.
`imag`			optional imaginary part.

Yields

The complex number. INVALID when either child is EMPTY or INVALID.

Notes

Without imag, follows single-argument complex(): numbers and complex-literal strings both convert.

Example

nu.run(nu.ToComplex(2, 3))[0]

(2+3j)

ToDict

The key/value pairs of the iterable child collected into a dict.

ToDict(value)

Path nu.core.ToDict. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			an iterable of `(key, value)` pairs.

Yields

The dict. INVALID when the child is EMPTY or INVALID.

Notes

A repeated key keeps the last pair's value, as for any Python dict.

Example

nu.run(nu.ToDict([("a", 1), ("b", 2)]))[0]

{'a': 1, 'b': 2}

ToFloat

The operand cast to float.

ToFloat(value)

Path nu.core.ToFloat. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			the value to convert.

Yields

The float. INVALID when the child is EMPTY or INVALID.

Example

nu.run(nu.ToFloat("3.14"))[0]

3.14

ToFrozenSet

The iterable child collected into a frozenset.

ToFrozenSet(value)

Path nu.core.ToFrozenSet. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			the iterable to collect.

Yields

The frozenset. INVALID when the child is EMPTY or INVALID.

Notes

Duplicates collapse and order is not preserved, as for any Python frozenset.

Example

nu.run(nu.ToFrozenSet([1, 1, 2]))[0]

frozenset({1, 2})

ToInt

The operand cast to int.

ToInt(value, base)

Path nu.core.ToInt. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 2 (2 required).

Arguments

Name	Type	Default	Meaning
`value`			the value to convert.
`base`			optional. When given, `value` is parsed as a string in this base instead of being converted directly.

Yields

The int. INVALID when either child is EMPTY or INVALID.

Notes

Without base, follows int(): numeric strings, floats (truncated toward zero) and bools all convert.
With base, follows int(str, base): value must be a string, and a malformed literal for that base raises.

Examples

nu.run(nu.ToInt("42"))[0]

nu.run(nu.ToInt("2a", 16))[0]

ToList

The iterable child collected into a list.

ToList(value)

Path nu.core.ToList. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			the iterable to collect.

Yields

The list. INVALID when the child is EMPTY or INVALID.

Example

nu.run(nu.ToList((1, 2, 3)))[0]

[1, 2, 3]

ToSet

The iterable child collected into a set.

ToSet(value)

Path nu.core.ToSet. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			the iterable to collect.

Yields

The set. INVALID when the child is EMPTY or INVALID.

Notes

Duplicates collapse and order is not preserved, as for any Python set.

Example

nu.run(nu.ToSet([1, 1, 2]))[0]

{1, 2}

ToStr

The operand cast to str.

ToStr(value)

Path nu.core.ToStr. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			the value to convert.

Yields

The string. INVALID when the child is EMPTY or INVALID.

Example

nu.run(nu.ToStr(42))[0]

'42'

ToTuple

The iterable child collected into a tuple.

ToTuple(value)

Path nu.core.ToTuple. Kind ScalarQuery, sort scalar_query, cardinality scalar. Arity 1 (1 required).

Arguments

Name	Type	Default	Meaning
`value`			the iterable to collect.

Yields

The tuple. INVALID when the child is EMPTY or INVALID.

Example

nu.run(nu.ToTuple([1, 2, 3]))[0]

(1, 2, 3)

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