105 lines
3.7 KiB
JavaScript
105 lines
3.7 KiB
JavaScript
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import { BaseOutputParser, OutputParserException, } from "@langchain/core/output_parsers";
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/**
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* Class to parse the output of an LLM call into a dictionary.
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* @augments BaseOutputParser
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*/
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export class RegexParser extends BaseOutputParser {
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static lc_name() {
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return "RegexParser";
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}
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get lc_attributes() {
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return {
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regex: this.lc_kwargs.regex,
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};
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}
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constructor(fields, outputKeys, defaultOutputKey) {
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// eslint-disable-next-line no-instanceof/no-instanceof
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if (typeof fields === "string" || fields instanceof RegExp) {
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// eslint-disable-next-line no-param-reassign, @typescript-eslint/no-non-null-assertion
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fields = { regex: fields, outputKeys: outputKeys, defaultOutputKey };
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}
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// eslint-disable-next-line no-instanceof/no-instanceof
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if (fields.regex instanceof RegExp) {
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// eslint-disable-next-line no-param-reassign
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fields.regex = {
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pattern: fields.regex.source,
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flags: fields.regex.flags,
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};
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}
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super(fields);
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Object.defineProperty(this, "lc_namespace", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: ["langchain", "output_parsers", "regex"]
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});
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Object.defineProperty(this, "lc_serializable", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: true
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});
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Object.defineProperty(this, "regex", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "outputKeys", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "defaultOutputKey", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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this.regex =
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// eslint-disable-next-line no-nested-ternary
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typeof fields.regex === "string"
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? new RegExp(fields.regex)
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: "pattern" in fields.regex
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? new RegExp(fields.regex.pattern, fields.regex.flags)
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: fields.regex;
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this.outputKeys = fields.outputKeys;
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this.defaultOutputKey = fields.defaultOutputKey;
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}
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_type() {
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return "regex_parser";
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}
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/**
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* Parses the given text using the regex pattern and returns a dictionary
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* with the parsed output. If the regex pattern does not match the text
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* and no defaultOutputKey is provided, throws an OutputParserException.
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* @param text The text to be parsed.
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* @returns A dictionary with the parsed output.
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*/
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async parse(text) {
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const match = text.match(this.regex);
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if (match) {
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return this.outputKeys.reduce((acc, key, index) => {
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acc[key] = match[index + 1];
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return acc;
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}, {});
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}
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if (this.defaultOutputKey === undefined) {
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throw new OutputParserException(`Could not parse output: ${text}`, text);
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}
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return this.outputKeys.reduce((acc, key) => {
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acc[key] = key === this.defaultOutputKey ? text : "";
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return acc;
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}, {});
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}
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/**
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* Returns a string with instructions on how the LLM output should be
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* formatted to match the regex pattern.
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* @returns A string with formatting instructions.
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*/
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getFormatInstructions() {
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return `Your response should match the following regex: ${this.regex}`;
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}
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}
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