Qubit Datatype

Runtime data type descriptors and policy-driven conversion utilities for Rust.

Installation

The default build contains the lightweight type vocabulary only:

[dependencies]
qubit-datatype = "0.6"

Enable the core conversion engine without rich-type dependencies:

[dependencies]
qubit-datatype = { version = "0.6", features = ["converter"] }

Compose the converter with only the rich families you use:

[dependencies]
qubit-datatype = { version = "0.6", features = ["converter", "chrono"] }

Features

Type vocabulary

DataType provides 25 stable runtime type names, an exhaustive ALL array, numeric classification methods, Serde support, and case-insensitive parsing. DataTypeOf maps Rust types to their runtime descriptors. Platform-sized isize and usize deliberately have no runtime descriptor.

use qubit_datatype::{DataType, DataTypeOf};

assert_eq!(i32::DATA_TYPE, DataType::Int32);
assert!(DataType::Int32.is_signed_integer());
assert_eq!(DataType::ALL.len(), 25);

Conversion contract

With the converter feature, DataConverter converts a single value, DataConverters converts an iterator, and ScalarStringDataConverters lazily splits a scalar string while preserving original source indices.

The default NumericConversionPolicy::Exact rejects truncation, rounding, and precision loss. Select Lossy explicitly to allow finite decimal/float to integer truncation toward zero, integer-to-float IEEE rounding, and Duration half-up rounding.

# #[cfg(feature = "converter")]
# {
use qubit_datatype::{
    DataConversionError, InvalidValueReason, DataConversionOptions,
    DataConverter,
};

assert!(matches!(
    DataConverter::from("3.9").to::<i32>(),
    Err(DataConversionError::InvalidValue {
        reason: InvalidValueReason::PrecisionLoss,
        ..
    }),
));

let lossy = DataConversionOptions::lossy();
assert_eq!(DataConverter::from(" 3.9 ").to_with::<i32>(&lossy), Ok(3));
# }

Conversion matrix

“Numeric” below includes primitive integers/floats and arbitrary-precision numbers. Invalid values return InvalidValue; type pairs outside this matrix return Unsupported; typed empty values return Missing.

Strings and booleans

Strings are not trimmed by default. Every string conversion calls StringConversionOptions::normalize once; enable trim explicitly. Blank strings can be preserved, treated as missing, or rejected.

Boolean text defaults to only true and false (ASCII case-insensitive). Numeric 0/1 handling is controlled separately by BooleanNumericPolicy::ZeroOrOne; NonZero and Reject are explicit alternatives. Literal builders are fallible, so true/false sets cannot overlap.

# #[cfg(feature = "converter")]
# {
use qubit_datatype::{
    DataConversionOptions, DataConverter, StringConversionOptions,
};

assert!(DataConverter::from(" true ").to::<bool>().is_err());
let options = DataConversionOptions::default().with_string_options(
    StringConversionOptions::default().with_trim(true),
);
assert_eq!(DataConverter::from(" true ").to_with::<bool>(&options), Ok(true));
# }

Duration

Duration text uses [0-9]+(ns|us|µs|μs|ms|s|m|h|d)?. Numeric input, suffixless strings, and output formatting have independent unit policies; the default profile uses milliseconds for all three. Whitespace, signs, and decimals are rejected. Large integer counts are decomposed into seconds and nanoseconds before range checking.

Duration-to-integer and Duration-to-String follow the numeric policy: Exact requires divisibility by the configured output unit; Lossy rounds half-up.

Rich text formats

• char: exactly one Unicode scalar value
• date: YYYY-MM-DD
• time: HH:MM:SS[.fraction], 1–9 fractional digits
• local date-time: YYYY-MM-DDTHH:MM:SS[.fraction]
• UTC instant: RFC 3339 with Z or an offset
• BigInt: signed decimal integer
• BigDecimal: decimal with optional exponent
• URL: absolute URL
• JSON: any valid JSON value
• StringMap: JSON object with unique keys and string values

Structured errors and collections

DataConversionError has exactly four variants: Missing, EmptyCollection, Unsupported, and InvalidValue { reason }. Missing, Unsupported, and InvalidValue store source and target DataType; EmptyCollection stores only the target type. Errors never retain or display the original value.

List failures use DataListConversionError::source_index. Empty-item Skip does not renumber later items, and to_first stops after the first retained item without validating the tail.

Development

cargo +1.94.0 test --no-default-features
cargo +1.94.0 test --all-features
./coverage.sh text
./align-ci.sh
./ci-check.sh

License

Licensed under the Apache License, Version 2.0. See LICENSE.

Author

Haixing Hu — Qubit Co. Ltd.