Adds Decimal methods to access the coefficient and exponent #593
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## main #593 +/- ##
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- Coverage 82.88% 82.87% -0.02%
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Files 110 111 +1
Lines 19250 19365 +115
Branches 19250 19365 +115
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+ Hits 15956 16049 +93
- Misses 1751 1773 +22
Partials 1543 1543
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| /// | ||
| /// Signed integers can infallibly implement `Into<Magnitude>` by using their | ||
| /// absolute value. | ||
| pub struct Magnitude(UInt); |
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🗺️ This type was moved into its own module. You'll see its definition appear further on.
| self.is_zero_with_sign(Sign::Positive) | ||
| } | ||
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| pub(crate) fn is_zero_with_sign(&self, test_sign: Sign) -> bool { |
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🗺️ This helper method is used in the implementation of both is_negative_zero() and is_positive_zero().
Users may wish to use is_negative_zero() before converting the Coefficient to an Int, as Int cannot represent negative zero natively. is_positive_zero() is provided mostly for symmetry.
| /// | ||
| /// Signed integers can infallibly implement `Into<Magnitude>` by using their | ||
| /// absolute value. | ||
| pub struct Magnitude(UInt); |
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🗺️ As mentioned above, this type was moved to its own module. It contains no new code apart from the From<BigUint> for Magnitude impl on line 32.
| type Error = (); | ||
| type Error = IonError; | ||
| fn try_from(value: $t) -> Result<Self, Self::Error> { | ||
| if value < 0 { | ||
| return Err(()); | ||
| return IonResult::illegal_operation("cannot convert a negative number to a UInt"); |
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🗺️ Previously, many conversions that would fail used () as their error type because the single mode of failure was obvious. (For example: trying to convert a negative Int to a UInt.) However, making these into IonError means they can be bubbled up with ? alongside all other IonResult-producing code.
illegal_operation isn't ideal; I'm open to creating an InvalidConversion error variant, but I don't expect users to will inspect conversion errors very deeply.
| ); | ||
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| // BigInt | ||
| let enormous_int = BigInt::from_str("1234567890123456789012345678901234567890").unwrap(); |
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Just for fun, this is a trick I sometimes use when making strings of numbers for length:
| let enormous_int = BigInt::from_str("1234567890123456789012345678901234567890").unwrap(); | |
| let enormous_int = BigInt::from_str("1234567891023456789202345678930234567894").unwrap(); |
This allows you to more easily figure out how long the string is, find a 9x0 and the digit x is the 10s place not a zero. The following 1 is not valuable (inferable from 234..), so I write 20, 30, what have you instead.
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| /// An arbitrary-precision Decimal type with a distinct representation of negative zero (`-0`). |
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Is it worth including some comment about what negative zero is for, what it means?
This PR:
Coefficienta publicly visible type.Decimal::coefficientmethod to access the coefficient.Decimal::exponentmethod to access the exponent.decimalmodule a directory instead of a flat fileMagnitudenewtype to its own moduleInt,UInt, andDecimalnow returnIonErrorinstead of()in the event of a failure.Fixes #405.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.