Add impl Bake for HashMap (#4295)

Fixes #4266

Author: robertbastian

CHANGELOG.md

@@ -30,7 +30,7 @@
         - CLI: Fix behavior of `--segmenter-lstm-root` such that it does not override `icuexportdata-root` (https://github.com/unicode-org/icu4x/pull/4277)
 - Utilities
     - `databake`
-        - Add implementations for `BTreeSet`, `BTreeMap` (https://github.com/unicode-org/icu4x/pull/4268, https://github.com/unicode-org/icu4x/pull/4274)  
+        - Add implementations for `HashSet`, `HashMap`, `BTreeSet`, `BTreeMap` (https://github.com/unicode-org/icu4x/pull/4268, https://github.com/unicode-org/icu4x/pull/4274, https://github.com/unicode-org/icu4x/pull/4295)  
         - Improvements to `databake::test_bake!()` (https://github.com/unicode-org/icu4x/pull/4182)
     - `litemap`
         - Implement `databake::Bake` on `LiteMap` (https://github.com/unicode-org/icu4x/pull/4275)

utils/databake/src/alloc.rs

@@ -106,6 +106,60 @@ fn btree_map() {
     );
 }
 
+impl<T> Bake for std::collections::HashSet<T>
+where
+    T: Bake,
+{
+    fn bake(&self, ctx: &CrateEnv) -> TokenStream {
+        ctx.insert("std");
+        let mut data = self.iter().map(|d| d.bake(ctx)).collect::<Vec<_>>();
+        data.sort_unstable_by_key(|data| data.to_string());
+        quote! {
+            std::collections::HashSet::from([#(#data),*])
+        }
+    }
+}
+
+#[test]
+fn hash_set() {
+    test_bake!(
+        std::collections::HashSet<u8>,
+        std::collections::HashSet::from([1u8, 2u8]),
+        std
+    );
+}
+
+impl<K, V> Bake for std::collections::HashMap<K, V>
+where
+    K: Bake,
+    V: Bake,
+{
+    fn bake(&self, ctx: &CrateEnv) -> TokenStream {
+        ctx.insert("std");
+        let mut data = self
+            .iter()
+            .map(|(k, v)| {
+                let k = k.bake(ctx);
+                let v = v.bake(ctx);
+                quote!((#k, #v))
+            })
+            .collect::<Vec<_>>();
+        data.sort_unstable_by_key(|data| data.to_string());
+        quote! {
+            std::collections::HashMap::from([#(#data),*])
+        }
+    }
+}
+
+#[test]
+fn hash_map() {
+    test_bake!(
+        std::collections::HashMap<u8, u8>,
+        std::collections::HashMap::from([(1u8, 2u8), (2u8, 4u8)]),
+        std
+    );
+}
+
 impl Bake for String {
     fn bake(&self, _: &CrateEnv) -> TokenStream {
         quote! {