Class: Langchain::OutputParsers::OutputFixingParser

Inherits:
Base
  • Object
show all
Defined in:
lib/langchain/output_parsers/output_fixing_parser.rb

Overview

Output Fixing Parser

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(llm:, parser:, prompt:) ⇒ OutputFixingParser

Initializes a new instance of the class.

Parameters:

Raises:

  • (ArgumentError) 


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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 14

def initialize(llm:, parser:, prompt:)
  raise ArgumentError.new("llm must be an instance of Langchain::LLM got: #{llm.class}") unless llm.is_a?(Langchain::LLM::Base)
  raise ArgumentError.new("parser must be an instance of Langchain::OutputParsers got #{parser.class}") unless parser.is_a?(Langchain::OutputParsers::Base)
  raise ArgumentError.new("prompt must be an instance of Langchain::Prompt::PromptTemplate got #{prompt.class}") unless prompt.is_a?(Langchain::Prompt::PromptTemplate)
  @llm = llm
  @parser = parser
  @prompt = prompt
end

Instance Attribute Details

#llm ⇒ Object (readonly)

Returns the value of attribute llm.



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 7

def llm
  @llm
end

#parser ⇒ Object (readonly)

Returns the value of attribute parser.



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 7

def parser
  @parser
end

#prompt ⇒ Object (readonly)

Returns the value of attribute prompt.



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 7

def prompt
  @prompt
end

Class Method Details

.from_llm(llm:, parser:, prompt: nil) ⇒ Object

Creates a new instance of the class using the given JSON::Schema.

Parameters:

Returns:

  • (Object) —

    A new instance of the class



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 67

def self.from_llm(llm:, parser:, prompt: nil)
  new(llm: llm, parser: parser, prompt: prompt || naive_fix_prompt)
end

Instance Method Details

#get_format_instructions ⇒ String

calls get_format_instructions on the @parser

according to the @schema.

Returns:

  • (String) —

    Instructions for how the output of a language model should be formatted



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 35

def get_format_instructions
  parser.get_format_instructions
end

#parse(completion) ⇒ Object

Parse the output of an LLM call, if fails with OutputParserException then call the LLM with a fix prompt in an attempt to get the correctly formatted response

Parameters:

  • completion (String) —

    Text output from the LLM call

Returns:

  • (Object) —

    object that is succesfully parsed by @parser.parse



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 46

def parse(completion)
  parser.parse(completion)
rescue OutputParserException => e
  new_completion = llm.chat(
    messages: [{role: "user",
                content: prompt.format(
                  instructions: parser.get_format_instructions,
                  completion: completion,
                  error: e
                )}]
  ).completion
  parser.parse(new_completion)
end

#to_h ⇒ Object 



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# File 'lib/langchain/output_parsers/output_fixing_parser.rb', line 23

def to_h
  {
    _type: "OutputFixingParser",
    parser: parser.to_h,
    prompt: prompt.to_h
  }
end