Fixed string cache

ext/polars/src/functions/string_cache.rs

@@ -1,3 +1,5 @@
+use crate::RbResult;
+use magnus::{RArray, Ruby, Value};
 use polars_core::StringCacheHolder;
 
 pub fn enable_string_cache() {
@@ -13,14 +15,15 @@ pub fn using_string_cache() -> bool {
 }
 
 #[magnus::wrap(class = "Polars::RbStringCacheHolder")]
-pub struct RbStringCacheHolder {
-    _inner: StringCacheHolder,
-}
+pub struct RbStringCacheHolder;
 
 impl RbStringCacheHolder {
     pub fn new() -> Self {
-        Self {
-            _inner: StringCacheHolder::hold(),
-        }
+        Self {}
+    }
+
+    pub fn hold(&self) -> RbResult<Value> {
+        let _hold = StringCacheHolder::hold();
+        Ruby::get().unwrap().yield_splat(RArray::new())
     }
 }

ext/polars/src/lib.rs

@@ -1049,6 +1049,7 @@ fn init(ruby: &Ruby) -> RbResult<()> {
     // string cache
     let class = module.define_class("RbStringCacheHolder", ruby.class_object())?;
     class.define_singleton_method("new", function!(RbStringCacheHolder::new, 0))?;
+    class.define_method("hold", method!(RbStringCacheHolder::hold, 0))?;
 
     Ok(())
 }

lib/polars/string_cache.rb

@@ -1,14 +1,9 @@
 module Polars
-  # @private
   # Context manager for enabling and disabling the global string cache.
   class StringCache
-    def initialize
-      raise Todo
-
+    def initialize(&block)
       @string_cache = RbStringCacheHolder.new
-      yield
-      # TODO fix
-      @string_cache = nil
+      @string_cache.hold(&block)
     end
   end
 

test/docs_test.rb

@@ -151,9 +151,6 @@ def assert_examples(method, cls)
     # TODO fix
     return if [:align_frames, :coalesce, :cum_sum_horizontal, :cumsum_horizontal, :to_titlecase].include?(method.name)
 
-    # TODO fix string cache
-    return if [:is_local, :to_local].include?(method.name)
-
     code = ""
     method.tags(:example).each do |example|
       # use variables from previous examples

test/string_cache_test.rb

@@ -0,0 +1,11 @@
+require_relative "test_helper"
+
+class StringCacheTest < Minitest::Test
+  def test_works
+    refute Polars.using_string_cache
+    Polars::StringCache.new do
+      assert Polars.using_string_cache
+    end
+    refute Polars.using_string_cache
+  end
+end