Specifically, the width and precision format specifiers are interpreted as
referring to the width of the grapheme clusters rather than the byte count of
the string. Note that grapheme clusters can differ in width.
If a precision is specified for a string, meaning its "maximum number of
characters", we consider this to limit the width displayed.
If there is a grapheme cluster whose width is greater than 1,
it might not be possible to get precisely the desired width.
In such cases, this last grapheme cluster is excluded from the output.
Note that the definitions used here are not consistent with the `string length`
builtin at the moment, but this has already been the case.
(cherry picked from commit 09eae92888)
Make fish-printf no longer depend on the widestring crate, as other clients
won't use it; instead this is an optional feature.
Make format strings a generic type, so that both narrow and wide strings can
serve. This removes a lot of the complexity around converting from narrow to
wide.
Add a README.md to this crate.
A few specific tests fail under i586 due to its inherent floating point
inaccuracy issues (rust-lang/rust#114479), so ignore these tests if certain
are met.
We have specific integration tests elsewhere in fish to check that even under
i586 we get mostly sane results, so this is OK. I tried to modify the assert
macros to check for a loose string match (up to one character difference) or an
f64 abs diff of less than epsilon, but it was a lot of code with little value
and increased the friction to contributing to the tests. Also, let's just
acknowledge the fact that all of i686, let alone i586 specifically, is a dead
end and not worth investing such time and effort into so long as it more or less
"works".
Closes#10474.
This adds a crate containing a new implementation of printf, ported from musl.
This has some advantages:
- locale support is direct instead of being "applied after".
- No dependencies on libc printf. No unsafe code at all.
- No more WideWrite - just uses std::fmt::Write.
- Rounding is handled directly in all cases, instead of relying on Rust and/or
libc.
- No essential dependency on WString.
- Supports %n.
- Implementation is more likely to be correct since it's based on a widely used
printf, instead of a low-traffic Rust crate.
- Significantly faster.
