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Add note to rust devel about the wchar builtin

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Henrik Hørlück Berg 2023-07-28 09:53:59 +02:00 committed by Johannes Altmanninger
parent fae090ea67
commit 1b018c8bfb
1 changed files with 20 additions and 1 deletions
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21
doc_internal/rust-devel.md
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@ -93,7 +93,8 @@ None of the Rust string types are nul-terminated. We're taking this opportunity
One may create a `&wstr` from a string literal using the `wchar::L!` macro:
```rust
use crate::wchar::{wstr, L!}
use crate::wchar::prelude::*;
// This imports wstr, the L! macro, WString, a ToWString trait that supplies .to_wstring() along with other things
fn get_shell_name() -> &'static wstr {
L!("fish")
@ -104,6 +105,7 @@ There is also a `widestrs` proc-macro which enables L as a _suffix_, to reduce t
```rust
use crate::wchar::{wstr, widestrs}
// also imported by the prelude
#[widestrs]
fn get_shell_name() -> &'static wstr {
@ -111,6 +113,23 @@ fn get_shell_name() -> &'static wstr {
}
```
#### The wchar prelude
We have a prelude to make working with these string types a whole lot more ergonomic. In particular `WExt` supplies the null-terminated-compatible `.char_at(usize)`,
and a whole lot more methods that makes porting C++ code easier. It is also preferred to use char-based-methods like `.char_count()` and `.slice_{from,to}()`
of the `WExt` trait over directly calling `.len()` and `[usize..]/[..usize]`, as that makes the code compatible with a potential future change to UTF8-strings.
```rust
pub(crate) mod prelude {
pub(crate) use crate::{
wchar::{wstr, IntoCharIter, WString, L},
wchar_ext::{ToWString, WExt},
wutil::{sprintf, wgettext, wgettext_fmt, wgettext_str},
};
pub(crate) use widestring_suffix::widestrs;
}
```
### Strings for FFI
`WString` and `&wstr` are the common strings used by Rust components. At the FII boundary there are some additional strings for interop. _All of these are temporary for the duration of the port._