ChatPromptTemplate.fromTemplates constructor

ChatPromptTemplate.fromTemplates(List<(ChatMessageType, String)> messages, { String? customRole, PartialValues? partialVariables, bool validateTemplate = true, })

Creates a ChatPromptTemplate from a list of pairs of chat message prompt template type and template.

Example:

final promptTemplate = ChatPromptTemplate.fromTemplates([
  (ChatMessageType.system, 'You are an assistant that translates {input_language} to {output_language}.'),
  (ChatMessageType.human, '{text}'),
]);
final prompt = promptTemplate.formatPrompt({
    'input_language': 'English',
    'output_language': 'French',
    'text': 'I love programming.',
});
final res = await chatModel.invoke(prompt);

• messages the list of pairs of type and templates.
• customRole the role of the message if type is ChatMessageType.custom.
• partialVariables the partial variables to use for the template.
• validateTemplate whether to validate the template.

Implementation

factory ChatPromptTemplate.fromTemplates(
  final List<(ChatMessageType, String)> messages, {
  final String? customRole,
  final PartialValues? partialVariables,
  final bool validateTemplate = true,
}) {
  final chatMessagePromptTemplates = messages
      .map((final message) {
        final (role, template) = message;
        return switch (role) {
          ChatMessageType.human =>
            HumanChatMessagePromptTemplate.fromTemplate(
              template,
              partialVariables: partialVariables,
              validateTemplate: false,
            ),
          ChatMessageType.ai => AIChatMessagePromptTemplate.fromTemplate(
            template,
            partialVariables: partialVariables,
            validateTemplate: false,
          ),
          ChatMessageType.system =>
            SystemChatMessagePromptTemplate.fromTemplate(
              template,
              partialVariables: partialVariables,
              validateTemplate: false,
            ),
          ChatMessageType.custom =>
            CustomChatMessagePromptTemplate.fromTemplate(
              template,
              role: ArgumentError.checkNotNull(customRole, 'customRole'),
              partialVariables: partialVariables,
              validateTemplate: false,
            ),
          ChatMessageType.messagePlaceholder => MessagePlaceholder(
            variableName: template,
          ),
          ChatMessageType.messagesPlaceholder => MessagesPlaceholder(
            variableName: template,
          ),
        };
      })
      .toList(growable: false);
  return ChatPromptTemplate.fromPromptMessages(
    chatMessagePromptTemplates,
    validateTemplate: validateTemplate,
  );
}