ARROW-15471: [R] ExtensionType support in R

r/DESCRIPTION

@@ -108,6 +108,7 @@ Collate:
     'table.R'
     'dplyr.R'
     'duckdb.R'
+    'extension.R'
     'feather.R'
     'field.R'
     'filesystem.R'

r/NAMESPACE

@@ -134,6 +134,8 @@ export(DictionaryArray)
 export(DirectoryPartitioning)
 export(DirectoryPartitioningFactory)
 export(Expression)
+export(ExtensionArray)
+export(ExtensionType)
 export(FeatherReader)
 export(Field)
 export(FileFormat)
@@ -267,6 +269,8 @@ export(match_arrow)
 export(matches)
 export(mmap_create)
 export(mmap_open)
+export(new_extension_array)
+export(new_extension_type)
 export(null)
 export(num_range)
 export(one_of)
@@ -282,6 +286,8 @@ export(read_parquet)
 export(read_schema)
 export(read_tsv_arrow)
 export(record_batch)
+export(register_extension_type)
+export(reregister_extension_type)
 export(s3_bucket)
 export(schema)
 export(set_cpu_count)
@@ -300,8 +306,11 @@ export(uint32)
 export(uint64)
 export(uint8)
 export(unify_schemas)
+export(unregister_extension_type)
 export(utf8)
 export(value_counts)
+export(vctrs_extension_array)
+export(vctrs_extension_type)
 export(write_arrow)
 export(write_csv_arrow)
 export(write_dataset)

r/R/arrow-package.R

@@ -80,6 +80,11 @@
     }
   }
 
+  if (arrow_available()) {
+    # register extension types that we use internally
+    reregister_extension_type(vctrs_extension_type(vctrs::unspecified()))
+  }
+
   invisible()
 }