render method

RenderedPrompt render(Iterable<ChatMessage> messages, { Iterable<AIFunctionDeclaration> tools = const <AIFunctionDeclaration>[], bool addGenerationPrompt = true, })

Renders messages (with optional tools) into a Mistral prompt.

Implementation

RenderedPrompt render(
  Iterable<ChatMessage> messages, {
  Iterable<AIFunctionDeclaration> tools = const <AIFunctionDeclaration>[],
  bool addGenerationPrompt = true,
}) {
  final all = messages.toList();
  final images = <Uint8List>[];

  var loopStart = 0;
  String? system;
  if (all.isNotEmpty && all.first.role == ChatRole.system) {
    final text = all.first.text;
    if (text.isNotEmpty) system = text;
    loopStart = 1;
  }

  final body = all.sublist(loopStart);
  final toolsBlock = _toolsBlock(tools);
  final lastUser = body.lastIndexWhere((m) => m.role == ChatRole.user);
  final out = StringBuffer();
  var firstUserSeen = false;

  for (var i = 0; i < body.length; i++) {
    final msg = body[i];
    if (msg.role == ChatRole.user) {
      final prefix = StringBuffer();
      if (i == lastUser && toolsBlock.isNotEmpty) prefix.write(toolsBlock);
      prefix.write(instStart);
      prefix.write(' ');
      if (!firstUserSeen && system != null) {
        prefix
          ..write(system)
          ..write('\n\n');
        firstUserSeen = true;
      }
      out
        ..write(prefix)
        ..write(_userContent(msg, images))
        ..write(' ')
        ..write(instEnd);
    } else if (msg.role == ChatRole.tool) {
      out
        ..write(toolResultsStart)
        ..write(_toolResult(msg))
        ..write(toolResultsEnd);
    } else {
      // Assistant turn: prose and/or a tool-call block, then EOS.
      final calls = msg.contents.whereType<FunctionCallContent>().toList();
      if (calls.isNotEmpty) {
        out
          ..write(toolCalls)
          ..write('[')
          ..write(calls.map(_callJson).join(', '))
          ..write(']');
      } else {
        out
          ..write(' ')
          ..write(msg.text);
      }
      out.write(eos);
    }
  }

  return RenderedPrompt(
    text: out.toString(),
    stopSequences: stopSequences,
    media: images,
  );
}