mustache_template_vars() — langchain Function Reference

Architecture documentation for the mustache_template_vars() function in string.py from the langchain codebase.

Function python PromptManagement ExampleSelection calls 1 called by 2

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PromptManagement→ ExampleSelection→ mustache_template_vars() — langchain Function Reference

Dependency Diagram

graph TD
  8a2cca12_2ece_1825_717e_3fd839530d4d["mustache_template_vars()"]
  a7a9f16f_a913_8e85_a792_d083dd92c428["string.py"]
  8a2cca12_2ece_1825_717e_3fd839530d4d -->|defined in| a7a9f16f_a913_8e85_a792_d083dd92c428
  8a2cca12_2ece_1825_717e_3fd839530d4d["mustache_template_vars()"]
  8a2cca12_2ece_1825_717e_3fd839530d4d -->|calls| 8a2cca12_2ece_1825_717e_3fd839530d4d
  f102027d_2a56_058a_1cf8_8ec4c6f8a103["get_template_variables()"]
  f102027d_2a56_058a_1cf8_8ec4c6f8a103 -->|calls| 8a2cca12_2ece_1825_717e_3fd839530d4d
  8a2cca12_2ece_1825_717e_3fd839530d4d["mustache_template_vars()"]
  8a2cca12_2ece_1825_717e_3fd839530d4d -->|calls| 8a2cca12_2ece_1825_717e_3fd839530d4d
  style 8a2cca12_2ece_1825_717e_3fd839530d4d fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/prompts/string.py lines 123–150

def mustache_template_vars(
    template: str,
) -> set[str]:
    """Get the top-level variables from a mustache template.

    For nested variables like `{{person.name}}`, only the top-level key (`person`) is
    returned.

    Args:
        template: The template string.

    Returns:
        The top-level variables from the template.
    """
    variables: set[str] = set()
    section_depth = 0
    for type_, key in mustache.tokenize(template):
        if type_ == "end":
            section_depth -= 1
        elif (
            type_ in {"variable", "section", "inverted section", "no escape"}
            and key != "."
            and section_depth == 0
        ):
            variables.add(key.split(".")[0])
        if type_ in {"section", "inverted section"}:
            section_depth += 1
    return variables