1.0 changes

[tormol]

I said I'd finish up my changes this weekend, and here they are.
It naturally turned into much more work than expected, mostly because in the process i found unsound trait impls, many inconsistencies, a way to make a const fn for creating AsciiChar from char, and many other small things I felt like changing.

Changelog:

• Remove unsound impl From<&mut AsciiStr> for &mut [u8] and for &mut str.
• Remove quickcheck.
• Rename AsciiStr.trim_left() and AsciiStr.trim_right() to trim_start() and trim_end().
• Rename AsciiChar::from{,_unchecked}() to from_ascii{,_unchecked}().
• Remove impls of deprecated std::ascii::AsciiExt trait.
• Rename some AsciiChar variants, most significantly Null to Nul (for consistency with CStr method names).
• Remove AsciiStr::new() (in preparation for making it const sooner or changing it).
• Make from_ascii_unchecked() non-generic (in preparation for making it const sooner).
• Change Chars iterator returned by AsciiStr::chars() to produce values instead of references.
• Change AsciiChar::is_whitespace() to return true for form-feed and vertical tab (for consistency with char::is_whitespace().
• Change many AsciiChar methods to take self by reference for maximum compatibility with u8 and char.
• Add slice_ascii_str() and get_ascii() to AsAsciiStr and slice_mut_ascii_str() to AsMutAsciiStr.
• Hide Lines and Split behind impl Trait.
• Change Chars and CharsMut from being typedefs for [AsciiChar] iterators to being newtypes.
• Require Rust 1.36 for 1.0.*, and allow later semver-compatible releases to increase it.
• Make most AsciiChar methods const fn and add AsciiChar::new().
• Implement AsRef<AsciiStr> for AsciiChar and AsciiStr, and AsMut<AsciiStr> for AsciiStr.
• Implement ToAsciiChar for i8, u16 and u32.
• Implement Clone, Copy and Eq for ToAsciiCharError.
• Add many is_xxx() methods to AsciiChar.

[tomprogrammer]

The requirement of rustc 1.36 seems a bit high. Debian for example packages 1.34.2 in Buster, which could be our baseline for rustc compatibility I think.

[tormol]

The idea was to allow us to use as many features as possible without increasing MSRV, but aving at least one 1.0 version usable with packaged rustc makes sense.
With 1.36 we could actually use alloc-in-'#![no_std], but we'll still need a "std" feature for ErrorandCStr`, so that can wait until later.
Because I don't want a patch release to break what previously happened to compile, the minimum supported version becomes 1.33.0 as that is the minimum version that compiles.

[tomprogrammer]

I only found some places where I have a different opinion about taking self or &self. Else all changes look fine.

[tormol]

Sorry for not responding for three weeks.
Despite being so close to the finish line I didn't have any motivation to pick this PR up again.

[tomprogrammer]

Thanks for the updates here, I think the PR is ready to be merged and published.

[tormol]

Changelog:

Breaking changes:

* Change `AsciiChar.is_whitespace()` to also return true for '\0xb' (vertical tab) and '\0xc' (form feed).
* Remove quickcheck feature.
* Remove `AsciiStr::new()`.
* Rename `AsciiChar::from()` and `AsciiChar::from_unchecked()` to `from_ascii()` and `from_ascii_unchecked()`.
* Rename several `AsciiChar.is_xxx()` methods to `is_ascii_xxx()` (for comsistency with std).
* Rename `AsciiChar::Null` to `Nul` (for consistency with eg. `CStr::from_bytes_with_nul()`).
* Rename `AsciiStr.trim_left()` and `AsciiStr.trim_right()` to `trim_start()` and `trim_end()`.
* Remove impls of the deprecated `std::ascii::AsciiExt` trait.
* Change iterators `Chars`, `CharsMut` and `CharsRef` from type aliases to newtypes.
* Return `impl Trait` from `AsciiStr.lines()` and `AsciiStr.split()`, and remove iterator types `Lines` and `Split`.
* Add `slice_ascii_str()`, `get_ascii()` and `unwrap_ascii()` to the `AsAsciiStr` trait.
* Add `slice_mut_ascii_str()` and `unwrap_ascii_mut()` to the `AsMutAsciiStr` trait.
* Require Rust 1.33.0 for 1.0.\*, and allow later semver-compatible 1.y.0 releases to increase it.

Additions:

* Add `const fn` `AsciiChar::new()` which panicks on invalid values.
* Make most `AsciiChar` methods `const fn`.
* Add multiple `AsciiChar::is_[ascii_]xxx()` methods.
* Implement `AsRef<AsciiStr>` for `AsciiChar`.
* Make `AsciiString`'s `Extend` and `FromIterator` impl generic over all `AsRef<AsciiStr>`.
* Implement inclusive range indexing for `AsciiStr` (and thereby `AsciiString`).
* Mark `AsciiStr` and `AsciiString` `#[repr(transparent)]` (to `[AsciiChar]` and `Vec<AsciiChar>` respectively).

Also, a README update which I had stashed away:

diff --git a/README.md b/README.md
index 192abf0..e054cf1 100644
--- a/README.md
+++ b/README.md
@@ -11,15 +11,16 @@ dependencies section in `Cargo.toml`:
 
 ```toml
 [dependencies]
-ascii = "0.9"
+ascii = "1.0"
\`\`\`
 
 ## Using ascii without libstd
 
 Most of `AsciiChar` and `AsciiStr` can be used without `std` by disabling the
 default features. The owned string type `AsciiString` and the conversion trait
-`IntoAsciiString` as well as all methods referring to these types are
-unavailable. The `Error` trait is also unavailable, but `description()` is made
+`IntoAsciiString` as well as all methods referring to these types and
+`CStr` and `CString` are unavailable.
+The `Error` trait is also unavailable, but `description()` is made
 available as an inherent method for `ToAsciiCharError` and `AsAsciiStrError`.
 
 To use the `ascii` crate in `core`-only mode in your cargo project just add the
@@ -27,7 +28,7 @@ following dependency declaration in `Cargo.toml`:
 
 ```toml
 [dependencies]
-ascii = { version = "0.9", default-features = false }
+ascii = { version = "1.0", default-features = false }
\`\`\`
 
 ## Minimum supported Rust version
@@ -36,7 +37,7 @@ The minimum Rust version for 1.0.\* releases is 1.33.0.
 Later 1.y.0 releases might require newer Rust versions, but the three most
 recent stable releases at the time of publishing will always be supported.  
 For example this means that if the current stable Rust version is 1.38 when
-ascii 1.1.0 is released, then ascii 1.1.* will not require a newer
+ascii 1.1.0 is released, then ascii 1.1.\* will not require a newer
 Rust version than 1.36.
 
 ## History

(to apply, replace "\`\`\`" with "```" and then run git apply).

EDIT: Updated release notes to include is_whitespace() change and remove 0.9.3 items.