import { BaseTranslator, isFilterEmpty, Comparators, Operators, } from "@langchain/core/structured_query"; function processValue(value) { /** Convert a value to a string and add single quotes if it is a string. */ if (typeof value === "string") { return `'${value}'`; } else { return String(value); } } export class VectaraTranslator extends BaseTranslator { constructor() { super(...arguments); Object.defineProperty(this, "allowedOperators", { enumerable: true, configurable: true, writable: true, value: [Operators.and, Operators.or] }); Object.defineProperty(this, "allowedComparators", { enumerable: true, configurable: true, writable: true, value: [ Comparators.eq, Comparators.ne, Comparators.lt, Comparators.lte, Comparators.gt, Comparators.gte, ] }); } formatFunction(func) { if (func in Comparators) { if (this.allowedComparators.length > 0 && this.allowedComparators.indexOf(func) === -1) { throw new Error(`Comparator ${func} not allowed. Allowed operators: ${this.allowedComparators.join(", ")}`); } } else if (func in Operators) { if (this.allowedOperators.length > 0 && this.allowedOperators.indexOf(func) === -1) { throw new Error(`Operator ${func} not allowed. Allowed operators: ${this.allowedOperators.join(", ")}`); } } else { throw new Error("Unknown comparator or operator"); } const mapDict = { and: " and ", or: " or ", eq: "=", ne: "!=", lt: "<", lte: "<=", gt: ">", gte: ">=", }; return mapDict[func]; } /** * Visits an operation and returns a VectaraOperationResult. The * operation's arguments are visited and the operator is formatted. * @param operation The operation to visit. * @returns A VectaraOperationResult. */ visitOperation(operation) { const args = operation.args?.map((arg) => arg.accept(this)); const operator = this.formatFunction(operation.operator); return `( ${args.join(operator)} )`; } /** * Visits a comparison and returns a VectaraComparisonResult. The * comparison's value is checked for type and the comparator is formatted. * Throws an error if the value type is not supported. * @param comparison The comparison to visit. * @returns A VectaraComparisonResult. */ visitComparison(comparison) { const comparator = this.formatFunction(comparison.comparator); return `( doc.${comparison.attribute} ${comparator} ${processValue(comparison.value)} )`; } /** * Visits a structured query and returns a VectaraStructuredQueryResult. * If the query has a filter, it is visited. * @param query The structured query to visit. * @returns A VectaraStructuredQueryResult. */ visitStructuredQuery(query) { let nextArg = {}; if (query.filter) { nextArg = { filter: { filter: query.filter.accept(this) }, }; } return nextArg; } mergeFilters(defaultFilter, generatedFilter, mergeType = "and", forceDefaultFilter = false) { if (isFilterEmpty(defaultFilter) && isFilterEmpty(generatedFilter)) { return undefined; } if (isFilterEmpty(defaultFilter) || mergeType === "replace") { if (isFilterEmpty(generatedFilter)) { return undefined; } return generatedFilter; } if (isFilterEmpty(generatedFilter)) { if (forceDefaultFilter) { return defaultFilter; } if (mergeType === "and") { return undefined; } return defaultFilter; } if (mergeType === "and") { return { filter: `${defaultFilter} and ${generatedFilter}`, }; } else if (mergeType === "or") { return { filter: `${defaultFilter} or ${generatedFilter}`, }; } else { throw new Error("Unknown merge type"); } } }