parser: add slice expr node to syntax tree (#707)

Author: sbdchd

PLAN.md

@@ -439,6 +439,36 @@ SELECT customer_id, merchant_id, request_id, count(*) from t
 group by all;
 ```
 
+and an action to go backwards:
+
+```sql
+SELECT customer_id, merchant_id, request_id, count(*) from t
+group by all;
+--        ^action:expand-group-by-all-names
+```
+
+becomes:
+
+```sql
+SELECT customer_id, merchant_id, request_id, count(*) from t
+group by customer_id, merchant_id, request_id;
+```
+
+or with column numbers:
+
+```sql
+SELECT customer_id, merchant_id, request_id, count(*) from t
+group by all;
+--        ^action:expand-group-by-all-numbers
+```
+
+becomes:
+
+```sql
+SELECT customer_id, merchant_id, request_id, count(*) from t
+group by 1, 2, 3;
+```
+
 ### Rule: unused column
 
 ```sql
@@ -1004,6 +1034,64 @@ select foo, "a" from t;
 select foo, 'a' from t;
 ```
 
+### Quick Fix: Quote and Unquote columns, tables, etc.
+
+```sql
+select "x" from "t";
+--     ^ Quick Fix: unquote
+```
+
+gives
+
+```sql
+select x from "t";
+```
+
+and vice versa:
+
+```sql
+select x from "t";
+--     ^ Quick Fix: quote
+```
+
+gives:
+
+Note: we have to be mindful of casing here,
+
+```sql
+select "x" from "t";
+```
+
+Note: there's some gotchas with this that we need to handle:
+
+```sql
+-- okay
+with t("X") as (select 1)
+select "X" from t;
+
+-- err
+with t("X") as (select 1)
+select X from t;
+
+-- err
+with t("X") as (select 1)
+select x from t;
+```
+
+or invalid column names:
+
+```sql
+-- ok
+with t("a-b") as (select 1)
+select "a-b" from t;
+
+-- err
+with t("a-b") as (select 1)
+select a-b from t;
+-- Query 1 ERROR at Line 2: ERROR:  column "a" does not exist
+-- LINE 2: select a-b from t;
+```
+
 ### Quick Fix: in array
 
 ```sql

crates/squawk_parser/src/generated/syntax_kind.rs

@@ -2120,14 +2120,14 @@ fn index_expr(p: &mut Parser<'_>, lhs: CompletedMarker) -> CompletedMarker {
         if p.eat(COLON) {
             // foo[:]
             if p.eat(R_BRACK) {
-                return m.complete(p, INDEX_EXPR);
+                return m.complete(p, SLICE_EXPR);
             } else {
                 // foo[:b]
                 if expr(p).is_none() {
                     p.error("expected an expression");
                 }
                 p.expect(R_BRACK);
-                return m.complete(p, INDEX_EXPR);
+                return m.complete(p, SLICE_EXPR);
             }
         }
         // foo[a]
@@ -2139,12 +2139,14 @@ fn index_expr(p: &mut Parser<'_>, lhs: CompletedMarker) -> CompletedMarker {
         if p.eat(COLON) {
             // foo[a:]
             if p.eat(R_BRACK) {
-                return m.complete(p, INDEX_EXPR);
+                return m.complete(p, SLICE_EXPR);
             }
             // foo[a:b]
             if expr(p).is_none() {
                 p.error("expected an expression");
             }
+            p.expect(R_BRACK);
+            return m.complete(p, SLICE_EXPR);
         }
         p.expect(R_BRACK);
     }

crates/squawk_parser/src/grammar.rs

@@ -728,8 +728,8 @@ SOURCE_FILE
       COMMA ","
       WHITESPACE " "
       COLUMN
-        INDEX_EXPR
-          INDEX_EXPR
+        SLICE_EXPR
+          SLICE_EXPR
             NAME_REF
               IDENT "board"
             L_BRACK "["

crates/squawk_parser/tests/snapshots/tests__insert_ok.snap

@@ -1416,8 +1416,8 @@ SOURCE_FILE
       WHITESPACE " "
       TARGET_LIST
         TARGET
-          INDEX_EXPR
-            INDEX_EXPR
+          SLICE_EXPR
+            SLICE_EXPR
               NAME_REF
                 IDENT "b"
               L_BRACK "["
@@ -1444,8 +1444,8 @@ SOURCE_FILE
       WHITESPACE " "
       TARGET_LIST
         TARGET
-          INDEX_EXPR
-            INDEX_EXPR
+          SLICE_EXPR
+            SLICE_EXPR
               NAME_REF
                 IDENT "c"
               L_BRACK "["
@@ -1468,8 +1468,8 @@ SOURCE_FILE
       WHITESPACE " "
       TARGET_LIST
         TARGET
-          INDEX_EXPR
-            INDEX_EXPR
+          SLICE_EXPR
+            SLICE_EXPR
               NAME_REF
                 IDENT "schedule"
               L_BRACK "["
@@ -3931,7 +3931,7 @@ SOURCE_FILE
       WHITESPACE " "
       TARGET_LIST
         TARGET
-          INDEX_EXPR
+          SLICE_EXPR
             LITERAL
               POSITIONAL_PARAM "$1"
             L_BRACK "["

crates/squawk_parser/tests/snapshots/tests__select_operators_ok.snap

@@ -78,6 +78,34 @@ impl ast::IndexExpr {
     }
 }
 
+impl ast::SliceExpr {
+    #[inline]
+    pub fn base(&self) -> Option<ast::Expr> {
+        support::children(&self.syntax).next()
+    }
+
+    #[inline]
+    pub fn start(&self) -> Option<ast::Expr> {
+        // With `select x[1:]`, we have two exprs, `x` and `1`.
+        // We skip over the first one, and then we want the second one, but we
+        // want to make sure we don't choose the end expr if instead we had:
+        // `select x[:1]`
+        let colon = self.colon_token()?;
+        support::children(&self.syntax)
+            .skip(1)
+            .find(|expr: &ast::Expr| expr.syntax().text_range().end() <= colon.text_range().start())
+    }
+
+    #[inline]
+    pub fn end(&self) -> Option<ast::Expr> {
+        // We want to make sure we get the last expr after the `:` which is the
+        // end of the slice, i.e., `2` in: `select x[:2]`
+        let colon = self.colon_token()?;
+        support::children(&self.syntax)
+            .find(|expr: &ast::Expr| expr.syntax().text_range().start() >= colon.text_range().end())
+    }
+}
+
 impl ast::BetweenExpr {
     #[inline]
     pub fn target(&self) -> Option<ast::Expr> {

crates/squawk_syntax/src/ast/generated/nodes.rs

@@ -509,6 +509,55 @@ fn index_expr() {
     assert_eq!(index.syntax().text(), "bar");
 }
 
+#[test]
+fn slice_expr() {
+    use insta::assert_snapshot;
+    let source_code = "
+        select x[1:2], x[2:], x[:3], x[:];
+    ";
+    let parse = SourceFile::parse(source_code);
+    assert!(parse.errors().is_empty());
+    let file: SourceFile = parse.tree();
+    let stmt = file.stmts().next().unwrap();
+    let ast::Stmt::Select(select) = stmt else {
+        unreachable!()
+    };
+    let select_clause = select.select_clause().unwrap();
+    let mut targets = select_clause.target_list().unwrap().targets();
+
+    let ast::Expr::SliceExpr(slice) = targets.next().unwrap().expr().unwrap() else {
+        unreachable!()
+    };
+    assert_snapshot!(slice.syntax(), @"x[1:2]");
+    assert_eq!(slice.base().unwrap().syntax().text(), "x");
+    assert_eq!(slice.start().unwrap().syntax().text(), "1");
+    assert_eq!(slice.end().unwrap().syntax().text(), "2");
+
+    let ast::Expr::SliceExpr(slice) = targets.next().unwrap().expr().unwrap() else {
+        unreachable!()
+    };
+    assert_snapshot!(slice.syntax(), @"x[2:]");
+    assert_eq!(slice.base().unwrap().syntax().text(), "x");
+    assert_eq!(slice.start().unwrap().syntax().text(), "2");
+    assert!(slice.end().is_none());
+
+    let ast::Expr::SliceExpr(slice) = targets.next().unwrap().expr().unwrap() else {
+        unreachable!()
+    };
+    assert_snapshot!(slice.syntax(), @"x[:3]");
+    assert_eq!(slice.base().unwrap().syntax().text(), "x");
+    assert!(slice.start().is_none());
+    assert_eq!(slice.end().unwrap().syntax().text(), "3");
+
+    let ast::Expr::SliceExpr(slice) = targets.next().unwrap().expr().unwrap() else {
+        unreachable!()
+    };
+    assert_snapshot!(slice.syntax(), @"x[:]");
+    assert_eq!(slice.base().unwrap().syntax().text(), "x");
+    assert!(slice.start().is_none());
+    assert!(slice.end().is_none());
+}
+
 #[test]
 fn field_expr() {
     let source_code = "