mirror of
https://github.com/fish-shell/fish-shell
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44 lines
1.4 KiB
Markdown
44 lines
1.4 KiB
Markdown
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# fish-printf
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The printf implementation used in [fish-shell](https://fishshell.com), based on musl printf.
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[](https://crates.io/crates/fish-printf)
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Licensed under the MIT license.
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### Usage
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Run `cargo add fish-printf` to add this crate to your `Cargo.toml` file.
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Also run `cargo add widestring` to add the widestring crate.
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### Notes
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fish-printf attempts to match the C standard for printf. It supports the following features:
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- Locale-specific formatting (decimal point, thousands separator, etc.)
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- Honors the current rounding mode.
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- Supports the `%n` modifier for counting characters written.
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fish-printf does not support positional arguments, such as `printf("%2$d", 1, 2)`.
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Prefixes like `l` or `ll` are recognized, but only used for validating the format string.
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The size of integer values is taken from the argument type.
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fish-printf can output to an `std::fmt::Write` object, or return a string.
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For reasons related to fish-shell, fish-printf has a feature "widestring" which uses the [widestring](https://crates.io/crates/widestring) crate. This is off by default.
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### Examples
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```rust
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use fish_printf::sprintf;
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// Create a `String` from a format string.
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let s = sprintf!("%0.5g", 123456.0) // 1.2346e+05
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// Append to an existing string.
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let s = String::new();
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sprintf!(=> &mut s, "%0.5g", 123456.0) // 1.2346e+05
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```
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