Class: OllamaChat::MessageList

Inherits:
Object
  • Object
show all
Includes:
MessageFormat, Pager, Term::ANSIColor
Defined in:
lib/ollama_chat/message_list.rb

Overview

A collection class for managing chat messages with support for system prompts, paged output, and conversation history.

This class provides functionality for storing, retrieving, and displaying chat messages in a structured manner. It handles system prompts separately from regular user and assistant messages, supports pagination for displaying conversations, and offers methods for manipulating message history including clearing, loading, saving, and dropping exchanges. The class integrates with Kramdown::ANSI for formatted output.

Examples:

Creating a new message list

chat = OllamaChat::Chat.new
messages = OllamaChat::MessageList.new(chat)

Adding messages to the list

messages << Ollama::Message.new(role: 'user', content: 'Hello')
messages << Ollama::Message.new(role: 'assistant', content: 'Hi there!')

Displaying conversation history

messages.list_conversation(5)  # Shows last 5 exchanges

Clearing messages

messages.clear  # Removes all non-system messages

Loading a saved conversation

messages.load_conversation('conversation.json')

Saving current conversation

messages.save_conversation('my_conversation.json')

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Pager

#determine_pager_command, #use_pager

Methods included from MessageFormat

#message_type, #talk_annotate, #think_annotate

Constructor Details

#initialize(chat) ⇒ MessageList

The initialize method sets up the message list for an OllamaChat session.

Parameters:



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# File 'lib/ollama_chat/message_list.rb', line 39

def initialize(chat)
  @chat     = chat
  @messages = []
end

Instance Attribute Details

#messages ⇒ Object (readonly)

The messages attribute reader returns the messages set for this object, initializing it lazily if needed.

The messages set is memoized, meaning it will only be created once per object instance and subsequent calls will return the same OllamaChat::MessageList instance.



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# File 'lib/ollama_chat/message_list.rb', line 58

def messages
  @messages
end

#system ⇒ Object (readonly)

The system attribute reader returns the system prompt for the chat session.



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# File 'lib/ollama_chat/message_list.rb', line 47

def system
  @system
end

Instance Method Details

#<<(message) ⇒ OllamaChat::MessageList

The << operator appends a message to the list of messages and returns self.

Parameters:

  • message (Ollama::Message) —

    the message to append

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 80

def <<(message)
  @messages << message
  self
end

#clear ⇒ OllamaChat::MessageList

The clear method removes all non-system messages from the message list.

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 70

def clear
  @messages.delete_if { _1.role != 'system' }
  self
end

#config ⇒ Object (private)

The config method provides access to the chat configuration object.

Returns:

  • (Object) —

    the configuration object associated with the chat instance



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# File 'lib/ollama_chat/message_list.rb', line 300

def config
  @chat.config
end

#drop(n) ⇒ Integer

Note:

  • System messages are preserved and not considered part of an exchange.

  • If only one incomplete exchange (a single user message) exists, it will be dropped first before removing complete exchanges.

Removes the last n exchanges from the message list. An exchange consists of a user and an assistant message. If only a single user message is present at the end, it will be removed first before proceeding with complete exchanges.

Parameters:

  • n (Integer) —

    The number of exchanges to remove.

Returns:

  • (Integer) —

    The actual number of complete exchanges removed. This may be less than n if there are not enough messages.



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# File 'lib/ollama_chat/message_list.rb', line 213

def drop(n)
  n = n.to_i.clamp(1, Float::INFINITY)
  non_system_messages = @messages.reject { _1.role == 'system' }
  if non_system_messages&.last&.role == 'user'
    @messages.pop
    n -= 1
  end
  if n == 0
    STDOUT.puts "Dropped the last exchange."
    return 1
  end
  if non_system_messages.empty?
    STDOUT.puts "No more exchanges can be dropped."
    return 0
  end
  m = 0
  while @messages.size > 1 && n > 0
    @messages.pop(2)
    m += 1
    n -= 1
  end
  STDOUT.puts "Dropped the last #{m} exchanges."
  m
end

#find_last(content: false) {|Message| ... } ⇒ OllamaChat::Message?

Note:

The method iterates in reverse order (reverse_each) so that the *most recent* matching message is returned. It also respects the content flag to skip empty messages, which is handy when the chat history contains empty messages e. g. when tool calling.

Find the last message that satisfies the supplied block.

Examples:

Find the last assistant message that contains content

last_assistant = message_list.find_last(content: true) { |m| m.role == 'assistant' }

Find the last user message regardless of content

last_user = message_list.find_last { |m| m.role == 'user' }

Parameters:

  • content (true, false) (defaults to: false) —

    If true, skip messages that have no content (m.content.present? is false). This is useful when you only care about messages that actually contain a payload (e.g. assistant replies, user queries, etc.).

Yields:

  • (Message) —

    yields each message in reverse order (from newest to oldest) until the block returns a truthy value.

Yield Parameters:

  • message (OllamaChat::Message) —

    the current message being inspected

Yield Returns:

  • (true, false) —

    whether the message matches the criteria

Returns:

  • (OllamaChat::Message, nil) —

    the first message that matches the block, or nil if none match.



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# File 'lib/ollama_chat/message_list.rb', line 119

def find_last(content: false, &block)
  @messages.reverse_each.find { |m|
    content and !m.content.present? and next
    block.(m)
  }
end

#last ⇒ Ollama::Message

Returns the last message from the conversation.

Returns:

  • (Ollama::Message) —

    The last message in the conversation, or nil if there are no messages.



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# File 'lib/ollama_chat/message_list.rb', line 89

def last
  @messages.last
end

#list_conversation(last = nil) ⇒ OllamaChat::MessageList

The list_conversation method displays the last n messages from the conversation.

Parameters:

  • last (Integer) (defaults to: nil) —

    the number of messages to display (default: nil)

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 173

def list_conversation(last = nil)
  last = (last || @messages.size).clamp(0, @messages.size)
  use_pager do |output|
    @messages[-last..-1].to_a.each do |message|
      output.puts message_text_for(message)
    end
  end
  self
end

#load_conversation(filename) ⇒ OllamaChat::MessageList

The load_conversation method loads a conversation from a file and populates the message list.

Parameters:

  • filename (String) —

    the path to the file containing the conversation

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 142

def load_conversation(filename)
  unless File.exist?(filename)
    STDERR.puts "File #{filename.to_s.inspect} doesn't exist. Choose another filename."
    return
  end
  @messages =
    File.open(filename, 'r') do |output|
      JSON(output.read).map {
        Ollama::Message.from_hash(_1 | { 'content' => nil })
      }
    end
  self
end

#message_text_for(message) ⇒ String (private)

The message_text_for method generates formatted text representation of a message including its role, content, thinking annotations, and associated images. It applies color coding to different message roles and uses markdown parsing when enabled. The method also handles special formatting for thinking annotations and image references within the message.

Parameters:

  • message (Object) —

    the message object containing role, content, thinking, and images

Returns:

  • (String) —

    the formatted text representation of the message



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# File 'lib/ollama_chat/message_list.rb', line 314

def message_text_for(message)
  role_color = case message.role
               when 'user' then 172
               when 'assistant' then 111
               when 'system' then 213
               else 210
               end
  thinking = if @chat.think_loud?
               think_annotate do
                 message.thinking.full? { @chat.markdown.on? ? @chat.kramdown_ansi_parse(_1) : _1 }
               end
             end
  content = message.content.full? { @chat.markdown.on? ? @chat.kramdown_ansi_parse(_1) : _1 }
  message_text = message_type(message.images) + " "
  message_text += bold { color(role_color) { message.role } }
  if thinking
    message_text += [ ?:, thinking, talk_annotate { content } ].compact.
      map { _1.chomp } * ?\n
  else
    message_text += ":\n#{content}"
  end
  message.images.full? { |images|
    message_text += "\nImages: " + italic { images.map(&:path) * ', ' }
  }
  message_text
end

#save_conversation(filename) ⇒ OllamaChat::MessageList

The save_conversation method saves the current conversation to a file.

Parameters:

  • filename (String) —

    the path where the conversation will be saved

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 161

def save_conversation(filename)
  File.open(filename, ?w) do |output|
    output.puts JSON(@messages)
  end
  self
end

#second_last ⇒ Ollama::Message

The second_last method returns the second-to-last message from the conversation if there are more than one non-system messages.

Returns:

  • (Ollama::Message) —

    the second-to-last message



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# File 'lib/ollama_chat/message_list.rb', line 130

def second_last
  if @messages.reject { _1.role == 'system' }.size > 1
    @messages[-2]
  end
end

#set_system_prompt(system) ⇒ OllamaChat::MessageList

Note:

This method:

  • Removes all existing system prompts from the message list

  • Adds the new system prompt to the beginning of the message list if provided

  • Handles edge cases such as clearing prompts when system is nil or false

Sets the system prompt for the chat session.

Parameters:

  • system (String, nil) —

    The new system prompt. If nil or false, clears the system prompt.

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 250

def set_system_prompt(system)
  @messages.reject! { |msg| msg.role == 'system' }
  if new_system_prompt = system.full?(:to_s)
    @system = new_system_prompt
    @messages.unshift(
      Ollama::Message.new(role: 'system', content: self.system)
    )
  else
    @system = nil
  end
  self
end

#show_last(n = nil) ⇒ OllamaChat::MessageList

The show_last method displays the text of the last message if it is not from the user. It uses a pager for output and returns the instance itself.

Returns:



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# File 'lib/ollama_chat/message_list.rb', line 187

def show_last(n = nil)
  n ||= 1
  messages = @messages.reject { |message| message.role == 'user' }
  n = n.clamp(0..messages.size)
  n <= 0 and return
  use_pager do |output|
    messages[-n..-1].to_a.each do |message|
      output.puts message_text_for(message)
    end
  end
  self
end

#show_system_prompt ⇒ self, NilClass

The show_system_prompt method displays the system prompt configured for the chat session.

It retrieves the system prompt from the @system instance variable, parses it using Kramdown::ANSI, and removes any trailing newlines. If the resulting string is empty, the method returns immediately.

Otherwise, it prints a formatted message to the console, including the configured system prompt and its length in characters.

Returns:

  • (self, NilClass) —

    nil if the system prompt is empty, otherwise self.



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# File 'lib/ollama_chat/message_list.rb', line 274

def show_system_prompt
  system_prompt = @chat.kramdown_ansi_parse(system.to_s).gsub(/\n+\z/, '').full?
  system_prompt or return
  STDOUT.puts <<~EOT
    Configured system prompt is:
    #{system_prompt}

    System prompt length: #{bold{system_prompt.size}} characters.
  EOT
  self
end

#size ⇒ Integer

Returns the number of messages stored in the message list.

Returns:

  • (Integer) —

    The size of the message list.



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# File 'lib/ollama_chat/message_list.rb', line 63

def size
  @messages.size
end

#to_ary ⇒ Array

The to_ary method converts the message list into an array of Ollama::Message objects.

Returns:

  • (Array) —

    An array of Ollama::Message objects representing the messages in the list.



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# File 'lib/ollama_chat/message_list.rb', line 291

def to_ary
  @messages.dup
end