Enable map access for numbers, multiple nesting levels (#356)

* enable integer keys for map access

* enable map access for number keys

* Add tests for string based map access

* MapAccess: unbox single quoted strings to always display double quoted strings for map access

* cargo fmt

* cargo clippy

* Fix compilation with nostd by avoiding format!

* fix codestyle

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

src/ast/mod.rs

@@ -251,7 +251,7 @@ pub enum Expr {
     },
     MapAccess {
         column: Box<Expr>,
-        key: String,
+        keys: Vec<Value>,
     },
     /// Scalar function call e.g. `LEFT(foo, 5)`
     Function(Function),
@@ -280,7 +280,17 @@ impl fmt::Display for Expr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Expr::Identifier(s) => write!(f, "{}", s),
-            Expr::MapAccess { column, key } => write!(f, "{}[\"{}\"]", column, key),
+            Expr::MapAccess { column, keys } => {
+                write!(f, "{}", column)?;
+                for k in keys {
+                    match k {
+                        k @ Value::Number(_, _) => write!(f, "[{}]", k)?,
+                        Value::SingleQuotedString(s) => write!(f, "[\"{}\"]", s)?,
+                        _ => write!(f, "[{}]", k)?,
+                    }
+                }
+                Ok(())
+            }
             Expr::Wildcard => f.write_str("*"),
             Expr::QualifiedWildcard(q) => write!(f, "{}.*", display_separated(q, ".")),
             Expr::CompoundIdentifier(s) => write!(f, "{}", display_separated(s, ".")),

src/parser.rs

@@ -952,13 +952,20 @@ impl<'a> Parser<'a> {
     }
 
     pub fn parse_map_access(&mut self, expr: Expr) -> Result<Expr, ParserError> {
-        let key = self.parse_literal_string()?;
+        let key = self.parse_map_key()?;
         let tok = self.consume_token(&Token::RBracket);
         debug!("Tok: {}", tok);
+        let mut key_parts: Vec<Value> = vec![key];
+        while self.consume_token(&Token::LBracket) {
+            let key = self.parse_map_key()?;
+            let tok = self.consume_token(&Token::RBracket);
+            debug!("Tok: {}", tok);
+            key_parts.push(key);
+        }
         match expr {
             e @ Expr::Identifier(_) | e @ Expr::CompoundIdentifier(_) => Ok(Expr::MapAccess {
                 column: Box::new(e),
-                key,
+                keys: key_parts,
             }),
             _ => Ok(expr),
         }
@@ -1997,6 +2004,21 @@ impl<'a> Parser<'a> {
         }
     }
 
+    /// Parse a map key string
+    pub fn parse_map_key(&mut self) -> Result<Value, ParserError> {
+        match self.next_token() {
+            Token::Word(Word { value, keyword, .. }) if keyword == Keyword::NoKeyword => {
+                Ok(Value::SingleQuotedString(value))
+            }
+            Token::SingleQuotedString(s) => Ok(Value::SingleQuotedString(s)),
+            #[cfg(not(feature = "bigdecimal"))]
+            Token::Number(s, _) => Ok(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),
+        }
+    }
+
     /// Parse a SQL datatype (in the context of a CREATE TABLE statement for example)
     pub fn parse_data_type(&mut self) -> Result<DataType, ParserError> {
         match self.next_token() {

tests/sqlparser_hive.rs

@@ -194,7 +194,7 @@ fn rename_table() {
 
 #[test]
 fn map_access() {
-    let rename = "SELECT a.b[\"asdf\"] FROM db.table WHERE a = 2";
+    let rename = r#"SELECT a.b["asdf"] FROM db.table WHERE a = 2"#;
     hive().verified_stmt(rename);
 }
 

tests/sqlparser_postgres.rs

@@ -18,6 +18,9 @@
 mod test_utils;
 use test_utils::*;
 
+#[cfg(feature = "bigdecimal")]
+use bigdecimal::BigDecimal;
+use sqlparser::ast::Expr::{Identifier, MapAccess};
 use sqlparser::ast::*;
 use sqlparser::dialect::{GenericDialect, PostgreSqlDialect};
 use sqlparser::parser::ParserError;
@@ -669,6 +672,57 @@ fn parse_pg_regex_match_ops() {
     }
 }
 
+#[test]
+fn parse_map_access_expr() {
+    #[cfg(not(feature = "bigdecimal"))]
+    let zero = "0".to_string();
+    #[cfg(feature = "bigdecimal")]
+    let zero = BigDecimal::parse_bytes(b"0", 10).unwrap();
+    let sql = "SELECT foo[0] FROM foos";
+    let select = pg_and_generic().verified_only_select(sql);
+    assert_eq!(
+        &MapAccess {
+            column: Box::new(Identifier(Ident {
+                value: "foo".to_string(),
+                quote_style: None
+            })),
+            keys: vec![Value::Number(zero.clone(), false)]
+        },
+        expr_from_projection(only(&select.projection)),
+    );
+    let sql = "SELECT foo[0][0] FROM foos";
+    let select = pg_and_generic().verified_only_select(sql);
+    assert_eq!(
+        &MapAccess {
+            column: Box::new(Identifier(Ident {
+                value: "foo".to_string(),
+                quote_style: None
+            })),
+            keys: vec![
+                Value::Number(zero.clone(), false),
+                Value::Number(zero.clone(), false)
+            ]
+        },
+        expr_from_projection(only(&select.projection)),
+    );
+    let sql = r#"SELECT bar[0]["baz"]["fooz"] FROM foos"#;
+    let select = pg_and_generic().verified_only_select(sql);
+    assert_eq!(
+        &MapAccess {
+            column: Box::new(Identifier(Ident {
+                value: "bar".to_string(),
+                quote_style: None
+            })),
+            keys: vec![
+                Value::Number(zero, false),
+                Value::SingleQuotedString("baz".to_string()),
+                Value::SingleQuotedString("fooz".to_string())
+            ]
+        },
+        expr_from_projection(only(&select.projection)),
+    );
+}
+
 fn pg() -> TestedDialects {
     TestedDialects {
         dialects: vec![Box::new(PostgreSqlDialect {})],