Support Dialect level precedence, update Postgres Dialect to match Postgres (#1360)

samuelcolvin · web-flow · commit a5480ae4982d · 2024-08-06T07:49:37.000-04:00
diff --git a/src/ast/operator.rs b/src/ast/operator.rs
@@ -151,7 +151,7 @@ pub enum BinaryOperator {
     Arrow,
     /// The `->>` operator.
     ///
-    /// On PostgreSQL, this operator that extracts a JSON object field or JSON
+    /// On PostgreSQL, this operator extracts a JSON object field or JSON
     /// array element and converts it to text, for example `'{"a":"b"}'::json
     /// ->> 'a'` or `[1, 2, 3]'::json ->> 2`.
     ///
diff --git a/src/dialect/mod.rs b/src/dialect/mod.rs
@@ -24,12 +24,13 @@ mod redshift;
 mod snowflake;
 mod sqlite;
 
-use crate::ast::{Expr, Statement};
 use core::any::{Any, TypeId};
 use core::fmt::Debug;
 use core::iter::Peekable;
 use core::str::Chars;
 
+use log::debug;
+
 pub use self::ansi::AnsiDialect;
 pub use self::bigquery::BigQueryDialect;
 pub use self::clickhouse::ClickHouseDialect;
@@ -43,8 +44,11 @@ pub use self::postgresql::PostgreSqlDialect;
 pub use self::redshift::RedshiftSqlDialect;
 pub use self::snowflake::SnowflakeDialect;
 pub use self::sqlite::SQLiteDialect;
+use crate::ast::{Expr, Statement};
 pub use crate::keywords;
+use crate::keywords::Keyword;
 use crate::parser::{Parser, ParserError};
+use crate::tokenizer::Token;
 
 #[cfg(not(feature = "std"))]
 use alloc::boxed::Box;
@@ -300,13 +304,172 @@ pub trait Dialect: Debug + Any {
         // return None to fall back to the default behavior
         None
     }
+
+    /// Get the precedence of the next token. This "full" method means all precedence logic and remain
+    /// in the dialect. while still allowing overriding the `get_next_precedence` method with the option to
+    /// fallback to the default behavior.
+    ///
+    /// Higher number => higher precedence
+    fn get_next_precedence_full(&self, parser: &Parser) -> Result<u8, ParserError> {
+        if let Some(precedence) = self.get_next_precedence(parser) {
+            return precedence;
+        }
+
+        let token = parser.peek_token();
+        debug!("get_next_precedence() {:?}", token);
+        match token.token {
+            Token::Word(w) if w.keyword == Keyword::OR => Ok(OR_PREC),
+            Token::Word(w) if w.keyword == Keyword::AND => Ok(AND_PREC),
+            Token::Word(w) if w.keyword == Keyword::XOR => Ok(XOR_PREC),
+
+            Token::Word(w) if w.keyword == Keyword::AT => {
+                match (
+                    parser.peek_nth_token(1).token,
+                    parser.peek_nth_token(2).token,
+                ) {
+                    (Token::Word(w), Token::Word(w2))
+                        if w.keyword == Keyword::TIME && w2.keyword == Keyword::ZONE =>
+                    {
+                        Ok(AT_TZ_PREC)
+                    }
+                    _ => Ok(UNKNOWN_PREC),
+                }
+            }
+
+            Token::Word(w) if w.keyword == Keyword::NOT => match parser.peek_nth_token(1).token {
+                // The precedence of NOT varies depending on keyword that
+                // follows it. If it is followed by IN, BETWEEN, or LIKE,
+                // it takes on the precedence of those tokens. Otherwise, it
+                // is not an infix operator, and therefore has zero
+                // precedence.
+                Token::Word(w) if w.keyword == Keyword::IN => Ok(BETWEEN_PREC),
+                Token::Word(w) if w.keyword == Keyword::BETWEEN => Ok(BETWEEN_PREC),
+                Token::Word(w) if w.keyword == Keyword::LIKE => Ok(LIKE_PREC),
+                Token::Word(w) if w.keyword == Keyword::ILIKE => Ok(LIKE_PREC),
+                Token::Word(w) if w.keyword == Keyword::RLIKE => Ok(LIKE_PREC),
+                Token::Word(w) if w.keyword == Keyword::REGEXP => Ok(LIKE_PREC),
+                Token::Word(w) if w.keyword == Keyword::SIMILAR => Ok(LIKE_PREC),
+                _ => Ok(UNKNOWN_PREC),
+            },
+            Token::Word(w) if w.keyword == Keyword::IS => Ok(IS_PREC),
+            Token::Word(w) if w.keyword == Keyword::IN => Ok(BETWEEN_PREC),
+            Token::Word(w) if w.keyword == Keyword::BETWEEN => Ok(BETWEEN_PREC),
+            Token::Word(w) if w.keyword == Keyword::LIKE => Ok(LIKE_PREC),
+            Token::Word(w) if w.keyword == Keyword::ILIKE => Ok(LIKE_PREC),
+            Token::Word(w) if w.keyword == Keyword::RLIKE => Ok(LIKE_PREC),
+            Token::Word(w) if w.keyword == Keyword::REGEXP => Ok(LIKE_PREC),
+            Token::Word(w) if w.keyword == Keyword::SIMILAR => Ok(LIKE_PREC),
+            Token::Word(w) if w.keyword == Keyword::OPERATOR => Ok(BETWEEN_PREC),
+            Token::Word(w) if w.keyword == Keyword::DIV => Ok(MUL_DIV_MOD_OP_PREC),
+            Token::Eq
+            | Token::Lt
+            | Token::LtEq
+            | Token::Neq
+            | Token::Gt
+            | Token::GtEq
+            | Token::DoubleEq
+            | Token::Tilde
+            | Token::TildeAsterisk
+            | Token::ExclamationMarkTilde
+            | Token::ExclamationMarkTildeAsterisk
+            | Token::DoubleTilde
+            | Token::DoubleTildeAsterisk
+            | Token::ExclamationMarkDoubleTilde
+            | Token::ExclamationMarkDoubleTildeAsterisk
+            | Token::Spaceship => Ok(EQ_PREC),
+            Token::Pipe => Ok(PIPE_PREC),
+            Token::Caret | Token::Sharp | Token::ShiftRight | Token::ShiftLeft => Ok(CARET_PREC),
+            Token::Ampersand => Ok(AMPERSAND_PREC),
+            Token::Plus | Token::Minus => Ok(PLUS_MINUS_PREC),
+            Token::Mul | Token::Div | Token::DuckIntDiv | Token::Mod | Token::StringConcat => {
+                Ok(MUL_DIV_MOD_OP_PREC)
+            }
+            Token::DoubleColon
+            | Token::ExclamationMark
+            | Token::LBracket
+            | Token::Overlap
+            | Token::CaretAt => Ok(DOUBLE_COLON_PREC),
+            // Token::Colon if (self as dyn Dialect).is::<SnowflakeDialect>() => Ok(DOUBLE_COLON_PREC),
+            Token::Arrow
+            | Token::LongArrow
+            | Token::HashArrow
+            | Token::HashLongArrow
+            | Token::AtArrow
+            | Token::ArrowAt
+            | Token::HashMinus
+            | Token::AtQuestion
+            | Token::AtAt
+            | Token::Question
+            | Token::QuestionAnd
+            | Token::QuestionPipe
+            | Token::CustomBinaryOperator(_) => Ok(PG_OTHER_PREC),
+            _ => Ok(UNKNOWN_PREC),
+        }
+    }
+
     /// Dialect-specific statement parser override
     fn parse_statement(&self, _parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
         // return None to fall back to the default behavior
         None
     }
+
+    /// The following precedence values are used directly by `Parse` or in dialects,
+    /// so have to be made public by the dialect.
+    fn prec_double_colon(&self) -> u8 {
+        DOUBLE_COLON_PREC
+    }
+
+    fn prec_mul_div_mod_op(&self) -> u8 {
+        MUL_DIV_MOD_OP_PREC
+    }
+
+    fn prec_plus_minus(&self) -> u8 {
+        PLUS_MINUS_PREC
+    }
+
+    fn prec_between(&self) -> u8 {
+        BETWEEN_PREC
+    }
+
+    fn prec_like(&self) -> u8 {
+        LIKE_PREC
+    }
+
+    fn prec_unary_not(&self) -> u8 {
+        UNARY_NOT_PREC
+    }
+
+    fn prec_unknown(&self) -> u8 {
+        UNKNOWN_PREC
+    }
 }
 
+// Define the lexical Precedence of operators.
+//
+// Uses (APPROXIMATELY) <https://www.postgresql.org/docs/7.0/operators.htm#AEN2026> as a reference
+// higher number = higher precedence
+//
+// NOTE: The pg documentation is incomplete, e.g. the AT TIME ZONE operator
+//       actually has higher precedence than addition.
+//       See <https://postgrespro.com/list/thread-id/2673331>.
+const DOUBLE_COLON_PREC: u8 = 50;
+const AT_TZ_PREC: u8 = 41;
+const MUL_DIV_MOD_OP_PREC: u8 = 40;
+const PLUS_MINUS_PREC: u8 = 30;
+const XOR_PREC: u8 = 24;
+const AMPERSAND_PREC: u8 = 23;
+const CARET_PREC: u8 = 22;
+const PIPE_PREC: u8 = 21;
+const BETWEEN_PREC: u8 = 20;
+const EQ_PREC: u8 = 20;
+const LIKE_PREC: u8 = 19;
+const IS_PREC: u8 = 17;
+const PG_OTHER_PREC: u8 = 16;
+const UNARY_NOT_PREC: u8 = 15;
+const AND_PREC: u8 = 10;
+const OR_PREC: u8 = 5;
+const UNKNOWN_PREC: u8 = 0;
+
 impl dyn Dialect {
     #[inline]
     pub fn is<T: Dialect>(&self) -> bool {
diff --git a/src/dialect/postgresql.rs b/src/dialect/postgresql.rs
@@ -9,6 +9,7 @@
 // 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 log::debug;
 
 use crate::ast::{CommentObject, Statement};
 use crate::dialect::Dialect;
@@ -20,6 +21,23 @@ use crate::tokenizer::Token;
 #[derive(Debug)]
 pub struct PostgreSqlDialect {}
 
+const DOUBLE_COLON_PREC: u8 = 140;
+const BRACKET_PREC: u8 = 130;
+const COLLATE_PREC: u8 = 120;
+const AT_TZ_PREC: u8 = 110;
+const CARET_PREC: u8 = 100;
+const MUL_DIV_MOD_OP_PREC: u8 = 90;
+const PLUS_MINUS_PREC: u8 = 80;
+// there's no XOR operator in PostgreSQL, but support it here to avoid breaking tests
+const XOR_PREC: u8 = 75;
+const PG_OTHER_PREC: u8 = 70;
+const BETWEEN_LIKE_PREC: u8 = 60;
+const EQ_PREC: u8 = 50;
+const IS_PREC: u8 = 40;
+const NOT_PREC: u8 = 30;
+const AND_PREC: u8 = 20;
+const OR_PREC: u8 = 10;
+
 impl Dialect for PostgreSqlDialect {
     fn identifier_quote_style(&self, _identifier: &str) -> Option<char> {
         Some('"')
@@ -67,6 +85,102 @@ impl Dialect for PostgreSqlDialect {
         )
     }
 
+    fn get_next_precedence(&self, parser: &Parser) -> Option<Result<u8, ParserError>> {
+        let token = parser.peek_token();
+        debug!("get_next_precedence() {:?}", token);
+
+        let precedence = match token.token {
+            Token::Word(w) if w.keyword == Keyword::OR => OR_PREC,
+            Token::Word(w) if w.keyword == Keyword::XOR => XOR_PREC,
+            Token::Word(w) if w.keyword == Keyword::AND => AND_PREC,
+            Token::Word(w) if w.keyword == Keyword::AT => {
+                match (
+                    parser.peek_nth_token(1).token,
+                    parser.peek_nth_token(2).token,
+                ) {
+                    (Token::Word(w), Token::Word(w2))
+                        if w.keyword == Keyword::TIME && w2.keyword == Keyword::ZONE =>
+                    {
+                        AT_TZ_PREC
+                    }
+                    _ => self.prec_unknown(),
+                }
+            }
+
+            Token::Word(w) if w.keyword == Keyword::NOT => match parser.peek_nth_token(1).token {
+                // The precedence of NOT varies depending on keyword that
+                // follows it. If it is followed by IN, BETWEEN, or LIKE,
+                // it takes on the precedence of those tokens. Otherwise, it
+                // is not an infix operator, and therefore has zero
+                // precedence.
+                Token::Word(w) if w.keyword == Keyword::IN => BETWEEN_LIKE_PREC,
+                Token::Word(w) if w.keyword == Keyword::BETWEEN => BETWEEN_LIKE_PREC,
+                Token::Word(w) if w.keyword == Keyword::LIKE => BETWEEN_LIKE_PREC,
+                Token::Word(w) if w.keyword == Keyword::ILIKE => BETWEEN_LIKE_PREC,
+                Token::Word(w) if w.keyword == Keyword::RLIKE => BETWEEN_LIKE_PREC,
+                Token::Word(w) if w.keyword == Keyword::REGEXP => BETWEEN_LIKE_PREC,
+                Token::Word(w) if w.keyword == Keyword::SIMILAR => BETWEEN_LIKE_PREC,
+                _ => self.prec_unknown(),
+            },
+            Token::Word(w) if w.keyword == Keyword::IS => IS_PREC,
+            Token::Word(w) if w.keyword == Keyword::IN => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::BETWEEN => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::LIKE => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::ILIKE => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::RLIKE => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::REGEXP => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::SIMILAR => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::OPERATOR => BETWEEN_LIKE_PREC,
+            Token::Word(w) if w.keyword == Keyword::DIV => MUL_DIV_MOD_OP_PREC,
+            Token::Word(w) if w.keyword == Keyword::COLLATE => COLLATE_PREC,
+            Token::Eq
+            | Token::Lt
+            | Token::LtEq
+            | Token::Neq
+            | Token::Gt
+            | Token::GtEq
+            | Token::DoubleEq
+            | Token::Tilde
+            | Token::TildeAsterisk
+            | Token::ExclamationMarkTilde
+            | Token::ExclamationMarkTildeAsterisk
+            | Token::DoubleTilde
+            | Token::DoubleTildeAsterisk
+            | Token::ExclamationMarkDoubleTilde
+            | Token::ExclamationMarkDoubleTildeAsterisk
+            | Token::Spaceship => EQ_PREC,
+            Token::Caret => CARET_PREC,
+            Token::Plus | Token::Minus => PLUS_MINUS_PREC,
+            Token::Mul | Token::Div | Token::Mod => MUL_DIV_MOD_OP_PREC,
+            Token::DoubleColon => DOUBLE_COLON_PREC,
+            Token::LBracket => BRACKET_PREC,
+            Token::Arrow
+            | Token::LongArrow
+            | Token::HashArrow
+            | Token::HashLongArrow
+            | Token::AtArrow
+            | Token::ArrowAt
+            | Token::HashMinus
+            | Token::AtQuestion
+            | Token::AtAt
+            | Token::Question
+            | Token::QuestionAnd
+            | Token::QuestionPipe
+            | Token::ExclamationMark
+            | Token::Overlap
+            | Token::CaretAt
+            | Token::StringConcat
+            | Token::Sharp
+            | Token::ShiftRight
+            | Token::ShiftLeft
+            | Token::Pipe
+            | Token::Ampersand
+            | Token::CustomBinaryOperator(_) => PG_OTHER_PREC,
+            _ => self.prec_unknown(),
+        };
+        Some(Ok(precedence))
+    }
+
     fn parse_statement(&self, parser: &mut Parser) -> Option<Result<Statement, ParserError>> {
         if parser.parse_keyword(Keyword::COMMENT) {
             Some(parse_comment(parser))
@@ -82,6 +196,26 @@ impl Dialect for PostgreSqlDialect {
     fn supports_group_by_expr(&self) -> bool {
         true
     }
+
+    fn prec_mul_div_mod_op(&self) -> u8 {
+        MUL_DIV_MOD_OP_PREC
+    }
+
+    fn prec_plus_minus(&self) -> u8 {
+        PLUS_MINUS_PREC
+    }
+
+    fn prec_between(&self) -> u8 {
+        BETWEEN_LIKE_PREC
+    }
+
+    fn prec_like(&self) -> u8 {
+        BETWEEN_LIKE_PREC
+    }
+
+    fn prec_unary_not(&self) -> u8 {
+        NOT_PREC
+    }
 }
 
 pub fn parse_comment(parser: &mut Parser) -> Result<Statement, ParserError> {
diff --git a/src/dialect/snowflake.rs b/src/dialect/snowflake.rs
@@ -145,6 +145,15 @@ impl Dialect for SnowflakeDialect {
 
         None
     }
+
+    fn get_next_precedence(&self, parser: &Parser) -> Option<Result<u8, ParserError>> {
+        let token = parser.peek_token();
+        // Snowflake supports the `:` cast operator unlike other dialects
+        match token.token {
+            Token::Colon => Some(Ok(self.prec_double_colon())),
+            _ => None,
+        }
+    }
 }
 
 /// Parse snowflake create table statement.
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
diff --git a/tests/sqlparser_postgres.rs b/tests/sqlparser_postgres.rs

Original file line number	Diff line number	Diff line change
`@@ -145,6 +145,15 @@ impl Dialect for SnowflakeDialect {`
`145`	`145`
`146`	`146`	`None`
`147`	`147`	`}`
	`148`	`+`
	`149`	`+ fn get_next_precedence(&self, parser: &Parser) -> Option<Result<u8, ParserError>> {`
	`150`	`+ let token = parser.peek_token();`
	`151`	+ // Snowflake supports the `:` cast operator unlike other dialects
	`152`	`+ match token.token {`
	`153`	`+ Token::Colon => Some(Ok(self.prec_double_colon())),`
	`154`	`+ _ => None,`
	`155`	`+ }`
	`156`	`+ }`
`148`	`157`	`}`
`149`	`158`
`150`	`159`	`/// Parse snowflake create table statement.`