Enable map access for function, add ClickHouse dialect (#382)

* 1 Add ClickHouse dialects.
2 Enable map access for function.

* 1 Fixed compilation errors.
2 Modify the code according to @alamb's comments.

* Fixed compilation errors.

src/ast/mod.rs

@@ -245,7 +245,7 @@ pub enum Expr {
     },
     MapAccess {
         column: Box<Expr>,
-        keys: Vec<Value>,
+        keys: Vec<Expr>,
     },
     /// Scalar function call e.g. `LEFT(foo, 5)`
     Function(Function),
@@ -284,8 +284,8 @@ impl fmt::Display for Expr {
                 write!(f, "{}", column)?;
                 for k in keys {
                     match k {
-                        k @ Value::Number(_, _) => write!(f, "[{}]", k)?,
-                        Value::SingleQuotedString(s) => write!(f, "[\"{}\"]", s)?,
+                        k @ Expr::Value(Value::Number(_, _)) => write!(f, "[{}]", k)?,
+                        Expr::Value(Value::SingleQuotedString(s)) => write!(f, "[\"{}\"]", s)?,
                         _ => write!(f, "[{}]", k)?,
                     }
                 }

src/dialect/clickhouse.rs

@@ -0,0 +1,27 @@
+// 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)]
+pub struct ClickHouseDialect {}
+
+impl Dialect for ClickHouseDialect {
+    fn is_identifier_start(&self, ch: char) -> bool {
+        // See https://clickhouse.com/docs/en/sql-reference/syntax/#syntax-identifiers
+        ('a'..='z').contains(&ch) || ('A'..='Z').contains(&ch) || ch == '_'
+    }
+
+    fn is_identifier_part(&self, ch: char) -> bool {
+        self.is_identifier_start(ch) || ('0'..='9').contains(&ch)
+    }
+}

src/dialect/mod.rs

@@ -11,6 +11,7 @@
 // limitations under the License.
 
 mod ansi;
+mod clickhouse;
 mod generic;
 mod hive;
 mod mssql;
@@ -23,6 +24,7 @@ use core::any::{Any, TypeId};
 use core::fmt::Debug;
 
 pub use self::ansi::AnsiDialect;
+pub use self::clickhouse::ClickHouseDialect;
 pub use self::generic::GenericDialect;
 pub use self::hive::HiveDialect;
 pub use self::mssql::MsSqlDialect;

src/parser.rs

@@ -1072,7 +1072,7 @@ impl<'a> Parser<'a> {
         let key = self.parse_map_key()?;
         let tok = self.consume_token(&Token::RBracket);
         debug!("Tok: {}", tok);
-        let mut key_parts: Vec<Value> = vec![key];
+        let mut key_parts: Vec<Expr> = vec![key];
         while self.consume_token(&Token::LBracket) {
             let key = self.parse_map_key()?;
             let tok = self.consume_token(&Token::RBracket);
@@ -2175,17 +2175,20 @@ impl<'a> Parser<'a> {
     }
 
     /// Parse a map key string
-    pub fn parse_map_key(&mut self) -> Result<Value, ParserError> {
+    pub fn parse_map_key(&mut self) -> Result<Expr, ParserError> {
         match self.next_token() {
             Token::Word(Word { value, keyword, .. }) if keyword == Keyword::NoKeyword => {
-                Ok(Value::SingleQuotedString(value))
+                if self.peek_token() == Token::LParen {
+                    return self.parse_function(ObjectName(vec![Ident::new(value)]));
+                }
+                Ok(Expr::Value(Value::SingleQuotedString(value)))
             }
-            Token::SingleQuotedString(s) => Ok(Value::SingleQuotedString(s)),
+            Token::SingleQuotedString(s) => Ok(Expr::Value(Value::SingleQuotedString(s))),
             #[cfg(not(feature = "bigdecimal"))]
-            Token::Number(s, _) => Ok(Value::Number(s, false)),
+            Token::Number(s, _) => Ok(Expr::Value(Value::Number(s, false))),
             #[cfg(feature = "bigdecimal")]
-            Token::Number(s, _) => Ok(Value::Number(s.parse().unwrap(), false)),
-            unexpected => self.expected("literal string or number", unexpected),
+            Token::Number(s, _) => Ok(Expr::Value(Value::Number(s.parse().unwrap(), false))),
+            unexpected => self.expected("literal string, number or function", unexpected),
         }
     }
 

tests/sqlparser_postgres.rs

@@ -730,7 +730,7 @@ fn parse_map_access_expr() {
                 value: "foo".to_string(),
                 quote_style: None
             })),
-            keys: vec![Value::Number(zero.clone(), false)]
+            keys: vec![Expr::Value(Value::Number(zero.clone(), false))]
         },
         expr_from_projection(only(&select.projection)),
     );
@@ -743,8 +743,8 @@ fn parse_map_access_expr() {
                 quote_style: None
             })),
             keys: vec![
-                Value::Number(zero.clone(), false),
-                Value::Number(zero.clone(), false)
+                Expr::Value(Value::Number(zero.clone(), false)),
+                Expr::Value(Value::Number(zero.clone(), false))
             ]
         },
         expr_from_projection(only(&select.projection)),
@@ -758,9 +758,9 @@ fn parse_map_access_expr() {
                 quote_style: None
             })),
             keys: vec![
-                Value::Number(zero, false),
-                Value::SingleQuotedString("baz".to_string()),
-                Value::SingleQuotedString("fooz".to_string())
+                Expr::Value(Value::Number(zero, false)),
+                Expr::Value(Value::SingleQuotedString("baz".to_string())),
+                Expr::Value(Value::SingleQuotedString("fooz".to_string()))
             ]
         },
         expr_from_projection(only(&select.projection)),

tests/sqpparser_clickhouse.rs

@@ -0,0 +1,57 @@
+// 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.
+
+#![warn(clippy::all)]
+//! Test SQL syntax specific to ClickHouse.
+
+#[macro_use]
+mod test_utils;
+use test_utils::*;
+
+use sqlparser::ast::Expr::{Identifier, MapAccess};
+use sqlparser::ast::*;
+
+use sqlparser::dialect::ClickHouseDialect;
+
+#[test]
+fn parse_map_access_expr() {
+    let sql = r#"SELECT string_values[indexOf(string_names, 'endpoint')] FROM foos"#;
+    let select = clickhouse().verified_only_select(sql);
+    assert_eq!(
+        &MapAccess {
+            column: Box::new(Identifier(Ident {
+                value: "string_values".to_string(),
+                quote_style: None
+            })),
+            keys: vec![Expr::Function(Function {
+                name: ObjectName(vec!["indexOf".into()]),
+                args: vec![
+                    FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::Identifier(Ident::new(
+                        "string_names"
+                    )))),
+                    FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::Value(
+                        Value::SingleQuotedString("endpoint".to_string())
+                    )))
+                ],
+                over: None,
+                distinct: false
+            })]
+        },
+        expr_from_projection(only(&select.projection)),
+    );
+}
+
+fn clickhouse() -> TestedDialects {
+    TestedDialects {
+        dialects: vec![Box::new(ClickHouseDialect {})],
+    }
+}