feat: extract logic for toString into visitor

docs/public/specs/esm/gaia.js

@@ -14,7 +14,7 @@ WITH prep AS (
   WHERE parallax BETWEEN -5 AND 20 AND phot_g_mean_mag IS NOT NULL AND bp_rp IS NOT NULL
 )
 SELECT
-  (1.340264 * lambda * cos(t)) / (sqrt(3)/2 * (1.340264 + (-0.081106 * 3 * t2) + (t6 * (0.000893 * 7 + 0.003796 * 9 * t2)))) AS u,
+  (1.340264 * "lambda" * cos(t)) / (sqrt(3)/2 * (1.340264 + (-0.081106 * 3 * t2) + (t6 * (0.000893 * 7 + 0.003796 * 9 * t2)))) AS u,
   t * (1.340264 + (-0.081106 * t2) + (t6 * (0.000893 + 0.003796 * t2))) AS v,
   * EXCLUDE('t', 't2', 't6')
 FROM prep`

docs/public/specs/json/gaia.json

@@ -4,7 +4,7 @@
     "description": "A 5M row sample of the 1.8B element Gaia star catalog.\nA `raster` sky map reveals our Milky Way galaxy. Select high parallax stars in the histogram to reveal a\n[Hertzsprung-Russel diagram](https://en.wikipedia.org/wiki/Hertzsprung%E2%80%93Russell_diagram)\nin the plot of stellar color vs. magnitude on the right.\n\n_You may need to wait a few seconds for the dataset to load._\n"
   },
   "data": {
-    "gaia": "-- compute u and v with natural earth projection\nWITH prep AS (\n  SELECT\n    radians((-l + 540) % 360 - 180) AS lambda,\n    radians(b) AS phi,\n    asin(sqrt(3)/2 * sin(phi)) AS t,\n    t^2 AS t2,\n    t2^3 AS t6,\n    *\n  FROM 'https://pub-1da360b43ceb401c809f68ca37c7f8a4.r2.dev/data/gaia-5m.parquet'\n  WHERE parallax BETWEEN -5 AND 20 AND phot_g_mean_mag IS NOT NULL AND bp_rp IS NOT NULL\n)\nSELECT\n  (1.340264 * lambda * cos(t)) / (sqrt(3)/2 * (1.340264 + (-0.081106 * 3 * t2) + (t6 * (0.000893 * 7 + 0.003796 * 9 * t2)))) AS u,\n  t * (1.340264 + (-0.081106 * t2) + (t6 * (0.000893 + 0.003796 * t2))) AS v,\n  * EXCLUDE('t', 't2', 't6')\nFROM prep\n"
+    "gaia": "-- compute u and v with natural earth projection\nWITH prep AS (\n  SELECT\n    radians((-l + 540) % 360 - 180) AS lambda,\n    radians(b) AS phi,\n    asin(sqrt(3)/2 * sin(phi)) AS t,\n    t^2 AS t2,\n    t2^3 AS t6,\n    *\n  FROM 'https://pub-1da360b43ceb401c809f68ca37c7f8a4.r2.dev/data/gaia-5m.parquet'\n  WHERE parallax BETWEEN -5 AND 20 AND phot_g_mean_mag IS NOT NULL AND bp_rp IS NOT NULL\n)\nSELECT\n  (1.340264 * \"lambda\" * cos(t)) / (sqrt(3)/2 * (1.340264 + (-0.081106 * 3 * t2) + (t6 * (0.000893 * 7 + 0.003796 * 9 * t2)))) AS u,\n  t * (1.340264 + (-0.081106 * t2) + (t6 * (0.000893 + 0.003796 * t2))) AS v,\n  * EXCLUDE('t', 't2', 't6')\nFROM prep\n"
   },
   "params": {
     "brush": {

docs/public/specs/yaml/gaia.yaml

@@ -22,7 +22,7 @@ data:
       WHERE parallax BETWEEN -5 AND 20 AND phot_g_mean_mag IS NOT NULL AND bp_rp IS NOT NULL
     )
     SELECT
-      (1.340264 * lambda * cos(t)) / (sqrt(3)/2 * (1.340264 + (-0.081106 * 3 * t2) + (t6 * (0.000893 * 7 + 0.003796 * 9 * t2)))) AS u,
+      (1.340264 * "lambda" * cos(t)) / (sqrt(3)/2 * (1.340264 + (-0.081106 * 3 * t2) + (t6 * (0.000893 * 7 + 0.003796 * 9 * t2)))) AS u,
       t * (1.340264 + (-0.081106 * t2) + (t6 * (0.000893 + 0.003796 * t2))) AS v,
       * EXCLUDE('t', 't2', 't6')
     FROM prep

packages/mosaic/sql/src/ast/aggregate.ts

@@ -104,22 +104,6 @@ export class AggregateNode extends ExprNode {
   frame(framedef: WindowFrameNode) {
     return this.window().frame(framedef);
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const { name, args, isDistinct, filter, order } = this;
-    const arg = [
-      isDistinct ? 'DISTINCT' : '',
-      args?.length ? args.join(', ')
-        : name.toLowerCase() === 'count' ?  '*'
-        : '',
-      order.length ? `ORDER BY ${order.join(', ')}` : ''
-    ].filter(x => x).join(' ');
-    const filt = filter ? ` FILTER (WHERE ${filter})` : '';
-    return `${name}(${arg})${filt}`;
-  }
 }
 
 /**

packages/mosaic/sql/src/ast/between-op.ts

@@ -40,13 +40,6 @@ export class BetweenOpNode extends AbstractBetweenOpNode {
   constructor(expr: ExprNode, extent?: Extent) {
     super(BETWEEN_OPERATOR, expr, extent);
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return super.toSQL('BETWEEN');
-  }
 }
 
 export class NotBetweenOpNode extends AbstractBetweenOpNode {
@@ -58,11 +51,4 @@ export class NotBetweenOpNode extends AbstractBetweenOpNode {
   constructor(expr: ExprNode, extent?: Extent) {
     super(NOT_BETWEEN_OPERATOR, expr, extent);
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return super.toSQL('NOT BETWEEN');
-  }
 }

packages/mosaic/sql/src/ast/binary-op.ts

@@ -21,11 +21,4 @@ export class BinaryOpNode extends ExprNode {
     this.left = left;
     this.right = right;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return `(${this.left} ${this.op} ${this.right})`;
-  }
 }

packages/mosaic/sql/src/ast/case.ts

@@ -52,17 +52,6 @@ export class CaseNode extends ExprNode {
   else(expr: ExprValue) {
     return new CaseNode(this.expr, this._when, asNode(expr));
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return 'CASE '
-      + (this.expr ? `${this.expr} ` : '')
-      + this._when.join(' ')
-      + (this._else ? ` ELSE ${this._else}` : '')
-      + ' END';
-  }
 }
 
 export class WhenNode extends SQLNode {
@@ -81,11 +70,4 @@ export class WhenNode extends SQLNode {
     this.when = when;
     this.then = then;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return `WHEN ${this.when} THEN ${this.then}`;
-  }
 }

packages/mosaic/sql/src/ast/cast.ts

@@ -17,12 +17,4 @@ export class CastNode extends ExprNode {
     this.expr = expr;
     this.cast = type;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    // TODO? could include check to see if parens are necessary
-    return `(${this.expr})::${this.cast}`;
-  }
 }

packages/mosaic/sql/src/ast/collate.ts

@@ -17,11 +17,4 @@ export class CollateNode extends ExprNode {
     this.expr = expr;
     this.collation = collation;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return `${this.expr} ${COLLATE} ${this.collation}`;
-  }
 }

packages/mosaic/sql/src/ast/column-ref.ts

@@ -1,6 +1,5 @@
 import type { TableRefNode } from './table-ref.js';
 import { COLUMN_REF } from '../constants.js';
-import { quoteIdentifier } from '../util/string.js';
 import { ExprNode } from './node.js';
 
 /**
@@ -31,16 +30,6 @@ export class ColumnRefNode extends ExprNode {
   get column() {
     return ''; // subclasses to override
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const { column, table } = this;
-    const tref = `${table ?? ''}`;
-    const id = column === '*' ? '*' : quoteIdentifier(column);
-    return (tref ? (tref + '.') : '') + id;
-  }
 }
 
 export class ColumnNameRefNode extends ColumnRefNode {

packages/mosaic/sql/src/ast/fragment.ts

@@ -18,11 +18,4 @@ export class FragmentNode extends ExprNode {
     super(FRAGMENT);
     this.spans = spans;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return this.spans.join('');
-  }
 }

packages/mosaic/sql/src/ast/from.ts

@@ -1,9 +1,6 @@
 import type { SampleClauseNode } from './sample.js';
 import { FROM_CLAUSE } from '../constants.js';
-import { quoteIdentifier } from '../util/string.js';
 import { SQLNode } from './node.js';
-import { isQuery } from './query.js';
-import { isTableRef } from './table-ref.js';
 
 /**
  * AST node corresponding to a table source which can appear
@@ -40,16 +37,4 @@ export class FromClauseNode extends FromNode {
   as(alias: string) {
     return new FromClauseNode(this.expr, alias, this.sample);
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const { expr, alias, sample } = this;
-    const ref = isQuery(expr) ? `(${expr})` : `${expr}`;
-    const from = alias && !(isTableRef(expr) && expr.table.join('.') === alias)
-      ? `${ref} AS ${quoteIdentifier(alias)}`
-      : `${ref}`;
-    return `${from}${sample ? ` TABLESAMPLE ${sample}` : ''}`;
-  }
 }

packages/mosaic/sql/src/ast/function.ts

@@ -17,12 +17,4 @@ export class FunctionNode extends ExprNode {
     this.name = name;
     this.args = args;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const { name, args } = this;
-    return `${name}(${args.join(', ')})`;
-  }
 }

packages/mosaic/sql/src/ast/in-op.ts

@@ -17,11 +17,4 @@ export class InOpNode extends ExprNode {
     this.expr = expr;
     this.values = values;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return `(${this.expr} IN (${this.values.join(', ')}))`;
-  }
 }

packages/mosaic/sql/src/ast/interval.ts

@@ -17,11 +17,4 @@ export class IntervalNode extends ExprNode {
     this.name = name;
     this.steps = steps;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return `INTERVAL ${this.steps} ${this.name}`;
-  }
 }

packages/mosaic/sql/src/ast/join.ts

@@ -63,23 +63,4 @@ export class JoinNode extends FromNode {
     this.using = using;
     this.sample = sample;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const { left, right, joinVariant, joinType, condition, using, sample } = this;
-    const variant = joinVariant === 'REGULAR' ? '' : `${joinVariant} `;
-    let type = '';
-    let cond = '';
-
-    if (joinVariant !== 'CROSS') {
-      type = joinType !== 'INNER' ? `${joinType} ` : '';
-      cond = condition ? ` ON ${condition}`
-        : using ? ` USING (${using?.join(', ')})`
-        : '';
-    }
-    const samp = sample ? ` USING SAMPLE ${sample}` : '';
-    return `${left} ${variant}${type}JOIN ${right}${cond}${samp}`;
-  }
 }

packages/mosaic/sql/src/ast/list.ts

@@ -13,11 +13,4 @@ export class ListNode extends ExprNode {
     super(LIST);
     this.values = values;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return `[${this.values.join(', ')}]`;
-  }
 }

packages/mosaic/sql/src/ast/literal.ts

@@ -13,13 +13,6 @@ export class LiteralNode extends ExprNode {
     super(LITERAL);
     this.value = value;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    return literalToSQL(this.value);
-  }
 }
 
 export function literalToSQL(value: unknown) {

packages/mosaic/sql/src/ast/logical-op.ts

@@ -17,16 +17,6 @@ export class LogicalOpNode<T extends ExprNode> extends ExprNode {
     this.op = op;
     this.clauses = clauses;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const c = this.clauses;
-    return c.length === 0 ? ''
-      : c.length === 1 ? `${c[0]}`
-      : `(${c.join(` ${this.op} `)})`;
-  }
 }
 
 export class AndNode<T extends ExprNode> extends LogicalOpNode<T> {

packages/mosaic/sql/src/ast/node.ts

@@ -1,3 +1,5 @@
+import type { SQLCodeGenerator } from '../visit/codegen/sql.js';
+
 /**
  * Check if a value is a SQL AST node.
  * @param value The value to check.
@@ -6,6 +8,16 @@ export function isNode(value: unknown): value is SQLNode {
   return value instanceof SQLNode;
 }
 
+let _defaultVisitor: SQLCodeGenerator | undefined;
+
+/**
+ * Set the default visitor for toString operations.
+ * This is used when no visitor is explicitly provided.
+ */
+export function setDefaultVisitor(visitor: SQLCodeGenerator) {
+  _defaultVisitor = visitor;
+}
+
 export class SQLNode {
   /** The SQL AST node type. */
   readonly type: string;
@@ -23,13 +35,28 @@ export class SQLNode {
    * @returns The shallow clone node.
    */
   clone(): this {
-    // @ts-expect-error use constructor
-    const clone = new this.constructor();
+    // @ts-expect-error use constructor with type
+    const clone = new this.constructor(this.type);
     for (const key in this) {
-      clone[key] = this[key];
+      if (key !== 'type') { // Skip type since it's already set by constructor
+        clone[key] = this[key];
+      }
     }
     return clone;
   }
+
+  /**
+   * Generate a SQL query string for this node using a specific dialect visitor.
+   * @param visitor Optional SQL visitor to use for string generation.
+   *  If not provided, uses the default visitor.
+   * @returns The SQL string representation.
+   */
+  toString(visitor: SQLCodeGenerator | undefined = _defaultVisitor): string {
+    if (!visitor) {
+      throw new Error('No visitor provided and no default visitor set.');
+    }
+    return visitor.toString(this);
+  }
 }
 
 /**

packages/mosaic/sql/src/ast/order-by.ts

@@ -21,18 +21,4 @@ export class OrderByNode extends ExprNode {
     this.desc = desc;
     this.nullsFirst = nullsFirst;
   }
-
-  /**
-   * Generate a SQL query string for this node.
-   */
-  toString() {
-    const { expr, desc, nullsFirst } = this;
-    const dir = desc ? ' DESC'
-      : desc === false ? ' ASC'
-      : '';
-    const nf = nullsFirst ? ' NULLS FIRST'
-      : nullsFirst === false ? ' NULLS LAST'
-      : '';
-    return `${expr}${dir}${nf}`;
-  }
 }