Update mapping::lookup so it is a const function

.github/workflows/ci.yaml

@@ -45,6 +45,38 @@ jobs:
       - name: Test with no default features
         run: cargo test --no-default-features
 
+  build-msrv:
+    name: Build (1.52.0)
+    runs-on: ubuntu-latest
+    env:
+      CARGO_INCREMENTAL: 0
+      RUSTFLAGS: -D warnings
+      RUST_BACKTRACE: 1
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: "1.52.0"
+          profile: minimal
+
+      - name: Compile
+        run: cargo build --verbose
+
+      - name: Compile tests
+        run: cargo test --no-run
+
+      - name: Test
+        run: cargo test
+
+      - name: Test with all features
+        run: cargo test --all-features
+
+      - name: Test with no default features
+        run: cargo test --no-default-features
+
   rust:
     name: Lint and format Rust
     runs-on: ubuntu-latest

README.md

@@ -108,6 +108,11 @@ All features are enabled by default.
 - **std** - Enable linking to the [Rust Standard Library]. Enabling this feature
   adds [`Error`] implementations to error types in this crate.
 
+### Minimum Supported Rust Version
+
+This crate requires at least Rust 1.52.0. This version can be bumped in minor
+releases.
+
 ## License
 
 `focaccia` is licensed under the [MIT License](LICENSE) (c) Ryan Lopopolo.

scripts/gen_case_lookups.rb

@@ -75,7 +75,7 @@
   #[must_use]
   #[allow(clippy::match_same_arms)]
   #[allow(clippy::too_many_lines)]
-  pub fn lookup(c: char, mode: Mode) -> Mapping {
+  pub const fn lookup(c: char, mode: Mode) -> Mapping {
       let codepoint = c as u32;
       let char_bytes = codepoint.to_be_bytes();
       let mid_byte = char_bytes[2];

src/folding/mapping/lookup.rs

@@ -3,7 +3,7 @@
 // This source is autogenerated. Do not modify it directly.
 // To make modfications to this code, see `scripts/gen_case_lookups.rb`.
 //
-// Last generated on 2020-12-30 17:16:47 UTC.
+// Last generated on 2021-05-17 14:03:38 UTC.
 //
 // Unicode version:
 // CaseFolding-13.0.0.txt
@@ -15,7 +15,7 @@ use super::{Mapping, Mode};
 #[must_use]
 #[allow(clippy::match_same_arms)]
 #[allow(clippy::too_many_lines)]
-pub fn lookup(c: char, mode: Mode) -> Mapping {
+pub const fn lookup(c: char, mode: Mode) -> Mapping {
     let codepoint = c as u32;
     let char_bytes = codepoint.to_be_bytes();
     let mid_byte = char_bytes[2];

tests/full_fold_exhaustive.rs

@@ -3,7 +3,7 @@
 // This source is autogenerated. Do not modify it directly.
 // To make modfications to this code, see `scripts/gen_case_lookups.rb`.
 //
-// Last generated on 2020-12-30 17:16:47 UTC.
+// Last generated on 2021-05-17 14:03:38 UTC.
 //
 // Unicode version:
 // CaseFolding-13.0.0.txt

tests/full_turkic_fold_exhaustive.rs

@@ -3,7 +3,7 @@
 // This source is autogenerated. Do not modify it directly.
 // To make modfications to this code, see `scripts/gen_case_lookups.rb`.
 //
-// Last generated on 2020-12-30 17:16:47 UTC.
+// Last generated on 2021-05-17 14:03:38 UTC.
 //
 // Unicode version:
 // CaseFolding-13.0.0.txt