Struct ChatTemplateBuilder 

pub struct ChatTemplateBuilder { /* private fields */ }

Builder for ChatTemplate, exposing the knobs that affect rendering semantics.

Defaults mirror the transformers reference environment: trim_blocks = true, lstrip_blocks = true, keep_trailing_newline = true, lenient undefined behavior, pycompat enabled, SystemClock.

Implementations

impl ChatTemplateBuilder

pub fn special_tokens_from(self, config: &TokenizerConfig) -> Self

Inject special tokens (bos_token, …) from a parsed tokenizer_config.json into the render context, replacing any already set. Use with ChatTemplate::builder when the template source is a standalone chat_template.jinja but the tokens still live in the config (see ChatTemplate::from_template_and_config).

pub fn template_name(self, name: impl Into<String>) -> Self

Select a named sub-template (e.g. "tool_use", "rag") when the config carries a list of them. Ignored for a single-string source.

pub fn clock(self, clock: impl Clock + 'static) -> Self

Inject a deterministic Clock for strftime_now (essential for golden tests).

pub fn pycompat(self, enabled: bool) -> Self

Enable/disable the pycompat Python-method shim. Default: enabled.

pub fn undefined_behavior(self, ub: UndefinedBehavior) -> Self

Override how undefined variables are treated. Default: UndefinedBehavior::Lenient.

pub fn build(self) -> Result<ChatTemplate, Error>

Compile the template. Returns Error::Compile on a Jinja syntax error, or Error::Config if a requested/needed named template can’t be resolved.