Implement std::fmt::Write for StringBuilder (#3638) #3659
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| write!(builder, "foo").unwrap(); | ||
| builder.append_value(""); | ||
| writeln!(builder, "bar").unwrap(); | ||
| builder.append_value(""); |
| @@ -235,6 +236,13 @@ impl<T: ByteArrayType, V: AsRef<T::Native>> Extend<Option<V>> for GenericByteBui | |||
| /// Array builder for [`GenericStringArray`][crate::GenericStringArray] | |||
| pub type GenericStringBuilder<O> = GenericByteBuilder<GenericStringType<O>>; | |||
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| impl<O: OffsetSizeTrait> Write for GenericStringBuilder<O> { | |||
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| impl<O: OffsetSizeTrait> Write for GenericStringBuilder<O> { | |
| /// Implement `Write` to support things like `write!(builder, ...`)) | |
| /// | |
| /// Note each individual call to `write_str` will result in a new row in the builder | |
| impl<O: OffsetSizeTrait> Write for GenericStringBuilder<O> { |
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It might be weird if someone puts a BufWriter in front of the builder, but with some comments it should be ok
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Each individual call won't result in a new row, you need to explicitly append an empty string to delimit the record
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Excellent thing to document I think
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This is pretty neat |
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Benchmark runs are scheduled for baseline = fb11792 and contender = 04500e7. 04500e7 is a master commit associated with this PR. Results will be available as each benchmark for each run completes. |
Which issue does this PR close?
Part of #3638
Rationale for this change
I want to use this in the cast kernels in #3647 to avoid needing to allocate strings per value, but split out into a separate PR to highlight, as the interface is perhaps a little strange.
What changes are included in this PR?
Are there any user-facing changes?