Initial commit

.github/workflows/lints.yml

@@ -0,0 +1,56 @@
+name: Lints
+on:
+  push:
+    branches: [ master ]
+
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Check
+        run: cargo check --workspace --examples --tests
+  check-formatting:
+    needs: [ check ]
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Format
+        run: cargo fmt --all -- --check
+  clippy:
+    needs: [ check ]
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Clippy
+        run: cargo clippy --workspace --examples --tests -- --warn clippy::pedantic --warn clippy::nursery --deny warnings

.github/workflows/tests.yml

@@ -0,0 +1,29 @@
+name: Tests
+
+on:
+  push:
+    branches: [ master ]
+
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  test:
+    needs: [ check ]
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Check
+        run: cargo check --workspace --examples --tests
+
+      - name: Test
+        run: cargo test --workspace

.gitignore

@@ -0,0 +1,3 @@
+/target
+/Cargo.lock
+/.idea

Cargo.toml

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+[package]
+name = "type-path"
+version = "0.1.0"
+edition = "2021"
+authors = ["Leonard. D <tigerros.gh@gmail.com>"]
+description = "Get the string array representation of a Rust type path"
+license = "MIT"
+repository = "https://github.com/tigerros/type-path"
+keywords = ["reflection", "macros", "no-std"]
+categories = ["rust-patterns", "no-std"]
+include = ["src/lib.rs", "README.md"]
+
+[dev-dependencies]
+trybuild = "1.0.0"

README.md

@@ -0,0 +1,16 @@
+[![tests badge]](https://github.com/tigerros/type-path/actions/workflows/tests.yml)
+[![lints badge]](https://github.com/tigerros/type-path/actions/workflows/lints.yml)
+[![docs.rs badge]](https://docs.rs/type-path/)
+[![crates.io badge]](https://crates.io/crates/type-path)
+[![license badge]](https://github.com/tigerros/type-path/blob/master/LICENSE)
+
+A tiny crate for getting the string array representation of a Rust type path, with type validation.
+Everything happens at compile-time.
+
+Check out the docs for everything else!
+
+[tests badge]: https://img.shields.io/github/actions/workflow/status/tigerros/type-path/tests.yml?label=tests&logo=data:image/svg+xml;base64,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
+[lints badge]: https://img.shields.io/github/actions/workflow/status/tigerros/type-path/lints.yml?label=lints&logo=data:image/svg+xml;base64,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
+[docs.rs badge]: https://img.shields.io/docsrs/type-path?logo=docs.rs&label=docs.rs
+[crates.io badge]: https://img.shields.io/crates/v/type-path?logo=rust
+[license badge]: https://img.shields.io/crates/l/type-path

src/lib.rs

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+#![no_std]
+
+//! # Guide
+//!
+//! The crate has just one macro: [`type_path!`](type_path). Check it out for syntax and returning details.
+//!
+//! You might be wondering why we're using an absolute path in the following example:
+//!
+//! ```rust
+//! use type_path::type_path;
+//! assert_eq!(type_path!(::std::io::BufWriter), ["::", "std", "io", "BufWriter"]);
+//! ```
+//!
+//! It's because macros have no way of knowing the scope of the given item.
+//!
+//! If it wasn't required, the following would happen, because macros only have access to the literal `Result` tokens,
+//! and no type information/scope etc.
+//!
+//! ```rust,ignore
+//! # use type_path::type_path;
+//! use std::io::Result;
+//! assert_eq!(type_path!(Result), ["Result"]);
+//! ```
+//!
+//! Now, the reliability aspect is gone, because even though the type exists,
+//! `"Result"` is extremely generic and almost certainly not what you want.
+//!
+//! You can also have an "everything" path (although you probably won't use this a lot):
+//!
+//! ```rust
+//! # use type_path::type_path;
+//! assert_eq!(type_path!(::std::io::*), ["::", "std", "io", "*"]);
+//! ```
+//!
+//! This doesn't compile, since `BufWrirer` doesn't exist:
+//!
+//! ```compile_fail,E0432
+//! # use type_path::type_path;
+//! type_path!(::std::io::BufWrirer);
+//! ```
+//!
+//! # Why?
+//! - **Reliability**:
+//!   The [`type_path!`](type_path) macro will check if the path you entered is valid, at compile time.
+//!   With other approaches, you can't be sure that the path is valid.
+//! - No dependencies.
+//! - You can use it in a no-std environment,
+
+const WHITESPACE: u8 = b'\t' | b'\n' | b'\r' | b' ';
+
+const fn bytes_trim_start(mut this: &[u8]) -> &[u8] {
+    loop {
+        match this {
+            [WHITESPACE, rem @ ..] => this = rem,
+            _ => return this,
+        }
+    }
+}
+
+const fn bytes_trim_end(mut this: &[u8]) -> &[u8] {
+    loop {
+        match this {
+            [rem @ .., WHITESPACE] => this = rem,
+            _ => return this,
+        }
+    }
+}
+
+const fn bytes_trim(this: &[u8]) -> &[u8] {
+    bytes_trim_start(bytes_trim_end(this))
+}
+
+/// **This is not intended to be used outside of this crate!**
+/// It's public because [`type_path!`](type_path) includes it in the expansion.
+///
+/// Trims a string at compile time.
+#[doc(hidden)]
+#[must_use]
+pub const fn trim(this: &str) -> &str {
+    let trimmed = bytes_trim(this.as_bytes());
+
+    // Safety: bytes_trim only removes ascii bytes
+    unsafe { core::str::from_utf8_unchecked(trimmed) }
+}
+
+/// **This is not intended to be used outside of this crate!**
+///
+/// Macro with one empty pattern `() => {};`.
+/// Used for enforcing that a meta variable (e.g., `$foo:tt`) is empty.
+#[macro_export]
+macro_rules! empty {
+    () => {};
+}
+
+/// # Syntax
+///
+/// *Ignore the macro source. It might be confusing and not helpful.*
+///
+/// There's 3 patterns:
+///
+/// - `::` prefix, with 1+ [identifiers] separated by `::`. E.g., `::path::to::Item`.
+/// This is an absolute path and will be resolved from the root of your project, regardless of scope.
+/// - Same as the first pattern, but with a `crate` prefix.
+/// Use this when you need to use types from the current crate.
+/// - Same as the first pattern, but ending in `::*`. E.g., `::path::to::prelude::*`.
+///
+/// # Returns
+///
+/// `[&'static str; N]`, where `N` is the amount of segments in the path, and `&str` is the segment.
+///
+/// The first item in the string array will be `"::"` or `"crate"`, depending on which prefix you use.
+///
+/// [identifiers]: https://doc.rust-lang.org/reference/identifiers.html "Rust identifier reference"
+#[macro_export]
+#[allow(clippy::crate_in_macro_def)]
+macro_rules! type_path {
+
+    (::$($segment:ident):: +$(::*$($empty:tt)? )?) => {{
+        #[allow(unused_imports)]
+        use :: $($segment)::+ $(::* $($crate::empty!($empty))?)?;
+
+        ["::", $($crate::trim(stringify!($segment))),+ $(, "*" $($crate::empty!($empty))?)?]
+    }};
+
+    (crate::$($segment:ident):: +$(::*$($empty:tt)? )?) => {{
+        #[allow(unused_imports)]
+        use crate :: $($segment)::+ $(::* $($crate::empty!($empty))?)?;
+
+        ["crate", $($crate::trim(stringify!($segment))),+ $(, "*" $($crate::empty!($empty))?)?]
+    }};
+}

tests/compile-fail/no_root_prefix.rs

@@ -0,0 +1,5 @@
+use type_path::type_path;
+
+fn main() {
+    type_path!(std::io::BufWriter);
+}

tests/compile-fail/no_root_prefix.stderr

@@ -0,0 +1,11 @@
+error: no rules expected the token `std`
+ --> tests/compile-fail/no_root_prefix.rs:4:16
+  |
+4 |     type_path!(std::io::BufWriter);
+  |                ^^^ no rules expected this token in macro call
+  |
+note: while trying to match `::`
+ --> src/lib.rs
+  |
+  |     (::$($segment:ident):: +$(::*$($empty:tt)? )?) => {{
+  |      ^^

tests/compile-fail/slice_instead_of_array.rs

@@ -0,0 +1,5 @@
+use type_path::type_path;
+
+const ITER_REPEAT_PATH: &[&str; 4] = type_path!(::std::iter::repeat);
+
+fn main() {}

tests/compile-fail/slice_instead_of_array.stderr

@@ -0,0 +1,7 @@
+error[E0308]: mismatched types
+ --> tests/compile-fail/slice_instead_of_array.rs:3:38
+  |
+3 | const ITER_REPEAT_PATH: &[&str; 4] = type_path!(::std::iter::repeat);
+  |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&[&str; 4]`, found `[&str; 4]`
+  |
+  = note: this error originates in the macro `type_path` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/compile-fail/unresolved_path.rs

@@ -0,0 +1,5 @@
+use type_path::type_path;
+
+fn main() {
+    type_path!(::std::io::BufWrirer);
+}

tests/compile-fail/unresolved_path.stderr

@@ -0,0 +1,10 @@
+error[E0432]: unresolved import `std::io::BufWrirer`
+ --> tests/compile-fail/unresolved_path.rs:4:5
+  |
+4 |     type_path!(::std::io::BufWrirer);
+  |     ^^^^^^^^^^^^^^^^^^^^^^---------^
+  |     |                     |
+  |     |                     help: a similar name exists in the module: `BufWriter`
+  |     no `BufWrirer` in `io`
+  |
+  = note: this error originates in the macro `type_path` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/compile-fail/wrong_array_length.rs

@@ -0,0 +1,5 @@
+use type_path::type_path;
+
+const ITER_REPEAT_PATH: [&str; 3] = type_path!(::std::iter::repeat);
+
+fn main() {}

tests/compile-fail/wrong_array_length.stderr

@@ -0,0 +1,9 @@
+error[E0308]: mismatched types
+ --> tests/compile-fail/wrong_array_length.rs:3:37
+  |
+3 | const ITER_REPEAT_PATH: [&str; 3] = type_path!(::std::iter::repeat);
+  |                                -    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected an array with a fixed size of 3 elements, found one with 4 elements
+  |                                |
+  |                                help: consider specifying the actual array length: `4`
+  |
+  = note: this error originates in the macro `type_path` (in Nightly builds, run with -Z macro-backtrace for more info)