Add BigQuery dialect (#490)

src/dialect/bigquery.rs

@@ -0,0 +1,35 @@
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::dialect::Dialect;
+
+#[derive(Debug, Default)]
+pub struct BigQueryDialect;
+
+impl Dialect for BigQueryDialect {
+    // See https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#identifiers
+    fn is_delimited_identifier_start(&self, ch: char) -> bool {
+        ch == '`'
+    }
+
+    fn is_identifier_start(&self, ch: char) -> bool {
+        ('a'..='z').contains(&ch) || ('A'..='Z').contains(&ch) || ch == '_'
+    }
+
+    fn is_identifier_part(&self, ch: char) -> bool {
+        ('a'..='z').contains(&ch)
+            || ('A'..='Z').contains(&ch)
+            || ('0'..='9').contains(&ch)
+            || ch == '_'
+            || ch == '-'
+    }
+}

src/dialect/mod.rs

@@ -11,6 +11,7 @@
 // limitations under the License.
 
 mod ansi;
+mod bigquery;
 mod clickhouse;
 mod generic;
 mod hive;
@@ -27,6 +28,7 @@ use core::iter::Peekable;
 use core::str::Chars;
 
 pub use self::ansi::AnsiDialect;
+pub use self::bigquery::BigQueryDialect;
 pub use self::clickhouse::ClickHouseDialect;
 pub use self::generic::GenericDialect;
 pub use self::hive::HiveDialect;