Tracking issue for FromStr trait usage in const fn
#59133
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A-const-fn
Area: const fn foo(..) {..}. Pure functions which can be applied at compile time.
C-tracking-issue
Category: A tracking issue for an RFC or an unstable feature.
T-libs-api
Relevant to the library API team, which will review and decide on the PR/issue.
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jonas-schievink
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Centril
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|
Isn't this just #67792 / rust-lang/rfcs#2632? |
This was referenced Jul 16, 2022
Dylan-DPC
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bors
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Mar 30, 2024
Make {integer}::from_str_radix constant
This commit makes FromStr on integers constant so that `const x: u32 = "23".parse();` works. More practical use-case is with environment variables at build time as discussed in rust-lang/rfcs#1907.
Tracking issue rust-lang#59133.
ACP: rust-lang/libs-team#74
|
It looks like the This would allow parsing ints at complie-time, e.g. from |
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tgross35
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Jul 26, 2024
…tr, r=dtolnay
Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str`
This PR stabilizes the feature `const_int_from_str`.
- ACP Issue: rust-lang/libs-team#74
- Implementation PR: rust-lang#99322
- Part of Tracking Issue: rust-lang#59133
API Change Diff:
```diff
impl {integer} {
- pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
+ pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
}
impl ParseIntError {
- pub fn kind(&self) -> &IntErrorKind;
+ pub const fn kind(&self) -> &IntErrorKind;
}
```
This makes it easier to parse integers at compile-time, e.g.
the example from the Tracking Issue:
```rust
env!("SOMETHING").parse::<usize>().unwrap()
```
could now be achived with
```rust
match usize::from_str_radix(env!("SOMETHING"), 10) {
Ok(val) => val,
Err(err) => panic!("Invalid value for SOMETHING environment variable."),
}
```
rather than having to depend on a library that implements or manually implement the parsing at compile-time.
---
Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved)
I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized.
- [x] ping Constant Evaluation WG
- [x] no unsafe involved
- [x] no `#[allow_internal_unstable]`
- [ ] usage of `intrinsic::const_eval_select` rust-lang#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time
- [ ] [rust-labg/libs-api FCP](rust-lang#124941 (comment))
tgross35
added a commit
to tgross35/rust
that referenced
this issue
Jul 26, 2024
…tr, r=dtolnay
Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str`
This PR stabilizes the feature `const_int_from_str`.
- ACP Issue: rust-lang/libs-team#74
- Implementation PR: rust-lang#99322
- Part of Tracking Issue: rust-lang#59133
API Change Diff:
```diff
impl {integer} {
- pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
+ pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
}
impl ParseIntError {
- pub fn kind(&self) -> &IntErrorKind;
+ pub const fn kind(&self) -> &IntErrorKind;
}
```
This makes it easier to parse integers at compile-time, e.g.
the example from the Tracking Issue:
```rust
env!("SOMETHING").parse::<usize>().unwrap()
```
could now be achived with
```rust
match usize::from_str_radix(env!("SOMETHING"), 10) {
Ok(val) => val,
Err(err) => panic!("Invalid value for SOMETHING environment variable."),
}
```
rather than having to depend on a library that implements or manually implement the parsing at compile-time.
---
Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved)
I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized.
- [x] ping Constant Evaluation WG
- [x] no unsafe involved
- [x] no `#[allow_internal_unstable]`
- [ ] usage of `intrinsic::const_eval_select` rust-lang#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time
- [ ] [rust-labg/libs-api FCP](rust-lang#124941 (comment))
tgross35
added a commit
to tgross35/rust
that referenced
this issue
Jul 26, 2024
…tr, r=dtolnay
Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str`
This PR stabilizes the feature `const_int_from_str`.
- ACP Issue: rust-lang/libs-team#74
- Implementation PR: rust-lang#99322
- Part of Tracking Issue: rust-lang#59133
API Change Diff:
```diff
impl {integer} {
- pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
+ pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
}
impl ParseIntError {
- pub fn kind(&self) -> &IntErrorKind;
+ pub const fn kind(&self) -> &IntErrorKind;
}
```
This makes it easier to parse integers at compile-time, e.g.
the example from the Tracking Issue:
```rust
env!("SOMETHING").parse::<usize>().unwrap()
```
could now be achived with
```rust
match usize::from_str_radix(env!("SOMETHING"), 10) {
Ok(val) => val,
Err(err) => panic!("Invalid value for SOMETHING environment variable."),
}
```
rather than having to depend on a library that implements or manually implement the parsing at compile-time.
---
Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved)
I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized.
- [x] ping Constant Evaluation WG
- [x] no unsafe involved
- [x] no `#[allow_internal_unstable]`
- [ ] usage of `intrinsic::const_eval_select` rust-lang#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time
- [ ] [rust-labg/libs-api FCP](rust-lang#124941 (comment))
rust-timer
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to rust-lang-ci/rust
that referenced
this issue
Jul 27, 2024
Rollup merge of rust-lang#124941 - Skgland:stabilize-const-int-from-str, r=dtolnay Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str` This PR stabilizes the feature `const_int_from_str`. - ACP Issue: rust-lang/libs-team#74 - Implementation PR: rust-lang#99322 - Part of Tracking Issue: rust-lang#59133 API Change Diff: ```diff impl {integer} { - pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>; + pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>; } impl ParseIntError { - pub fn kind(&self) -> &IntErrorKind; + pub const fn kind(&self) -> &IntErrorKind; } ``` This makes it easier to parse integers at compile-time, e.g. the example from the Tracking Issue: ```rust env!("SOMETHING").parse::<usize>().unwrap() ``` could now be achived with ```rust match usize::from_str_radix(env!("SOMETHING"), 10) { Ok(val) => val, Err(err) => panic!("Invalid value for SOMETHING environment variable."), } ``` rather than having to depend on a library that implements or manually implement the parsing at compile-time. --- Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved) I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized. - [x] ping Constant Evaluation WG - [x] no unsafe involved - [x] no `#[allow_internal_unstable]` - [ ] usage of `intrinsic::const_eval_select` rust-lang#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time - [ ] [rust-labg/libs-api FCP](rust-lang#124941 (comment))
flip1995
pushed a commit
to flip1995/rust-clippy
that referenced
this issue
Aug 8, 2024
…lnay
Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str`
This PR stabilizes the feature `const_int_from_str`.
- ACP Issue: rust-lang/libs-team#74
- Implementation PR: rust-lang/rust#99322
- Part of Tracking Issue: rust-lang/rust#59133
API Change Diff:
```diff
impl {integer} {
- pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
+ pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
}
impl ParseIntError {
- pub fn kind(&self) -> &IntErrorKind;
+ pub const fn kind(&self) -> &IntErrorKind;
}
```
This makes it easier to parse integers at compile-time, e.g.
the example from the Tracking Issue:
```rust
env!("SOMETHING").parse::<usize>().unwrap()
```
could now be achived with
```rust
match usize::from_str_radix(env!("SOMETHING"), 10) {
Ok(val) => val,
Err(err) => panic!("Invalid value for SOMETHING environment variable."),
}
```
rather than having to depend on a library that implements or manually implement the parsing at compile-time.
---
Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved)
I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized.
- [x] ping Constant Evaluation WG
- [x] no unsafe involved
- [x] no `#[allow_internal_unstable]`
- [ ] usage of `intrinsic::const_eval_select` rust-lang/rust#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time
- [ ] [rust-labg/libs-api FCP](rust-lang/rust#124941 (comment))
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Because Rust already have macros that evaluate on compile time to strings I think converting them to ints in a
const fnis a very nice feature.e.g.
env!("SOMETHING").parse::<usize>().unwrap()I opened this Issue as part of: #57563
Interested to hear if other people want this and if it's already exists as part of a different issue/RFC
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