@uwdata/mosaic-sql/dist/src/util/function.js

SQL query construction and analysis.

import { AggregateNode } from '../ast/aggregate.js';
import { FunctionNode } from '../ast/function.js';
import { WindowFunctionNode, WindowNode } from '../ast/window.js';
import { asNode } from './ast.js';
/**
 * Test if an AST node is a specific function call.
 * @param node The SQL AST node to test.
 * @param name The function name.
 */
export function isFunctionCall(node, name) {
    return node instanceof FunctionNode && node.name === name;
}
/**
 * Create a new function call AST node.
 * @param name The function name.
 * @param args The function arguments.
 */
export function fn(name, ...args) {
    return new FunctionNode(name, argsList(args).map(asNode));
}
/**
 * Create a new aggregate function AST node.
 * @param name The function name.
 * @param args The function arguments.
 */
export function aggFn(name, ...args) {
    return new AggregateNode(name, argsList(args).map(asNode));
}
/**
 * Create a new window AST node. The output node has an empty window
 * definition. Use chained calls such as `partitionby` and `orderby`
 * to specify the window settings.
 * @param name The function name.
 * @param args The function arguments.
 */
export function winFn(name, ...args) {
    return new WindowNode(new WindowFunctionNode(name, argsList(args).map(asNode)));
}
/**
 * Process a list of expression inputs. Nested arrays are flattened,
 * null results are removed, and each input is cast to a SQL AST node.
 * @param list The list of expression inputs.
 * @param cast A function that casts an input value
 *  to a desired type. By default, `asNode` is used to coerce
 *  inputs to AST nodes as needed.
 */
export function exprList(list, cast) {
    return list.flat().filter(x => x != null).map(x => cast(x));
}
/**
 * Process a list of expression inputs. Nested arrays are flattened,
 * null results are removed, and each input is cast (as needed) to
 * be a proper SQL AST node. By default, strings are assumed to be
 * column names, while other primitive values map to SQL literals.
 * Use an alternative *cast* function to change this behavior.
 * @param list The list of expression inputs.
 */
export function nodeList(list) {
    return exprList(list, asNode);
}
/**
 * Process a list of function arguments, stripping any undefined
 * values from the end of the list.
 * @param list The input function arguments.
 */
export function argsList(list) {
    const n = list.length;
    let i = n;
    for (; i > 0 && list[i - 1] === undefined; --i)
        ;
    return i < n ? list.slice(0, i) : list;
}
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