# loop_context URL: /kida/api/template/loop_context/ Section: template Description: Loop iteration metadata for Kida ``{% for %}`` and ``{% async for %}`` blocks. --- > For a complete page index, fetch /kida/llms.txt. Open LLM text (/kida/api/template/loop_context/index.txt) Share with AI Ask Claude (https://claude.ai/new?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fkida%2Fapi%2Ftemplate%2Floop_context%2Findex.txt) Ask ChatGPT (https://chatgpt.com/?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fkida%2Fapi%2Ftemplate%2Floop_context%2Findex.txt) Ask Gemini (https://gemini.google.com/app?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fkida%2Fapi%2Ftemplate%2Floop_context%2Findex.txt) Ask Copilot (https://copilot.microsoft.com/?q=Please%20help%20me%20understand%20this%20documentation%3A%20%2Fkida%2Fapi%2Ftemplate%2Floop_context%2Findex.txt) Module # `template.loop_context` Loop iteration metadata for Kida`{% for %}` and `{% async for %}`blocks. 2Classes1Function ## Classes `LoopContext` 13 ▼ Loop iteration metadata accessible as `loop` inside `{% for %}` blocks. Provides index tracking, b… Loop iteration metadata accessible as`loop` inside `{% for %}`blocks. Provides index tracking, boundary detection, and utility methods for common iteration patterns. All properties are computed on-access. Properties: index: 1-based iteration count (1, 2, 3, ...) index0: 0-based iteration count (0, 1, 2, ...) first: True on the first iteration last: True on the final iteration length: Total number of items in the sequence revindex: Reverse 1-based index (counts down to 1) revindex0: Reverse 0-based index (counts down to 0) previtem: Previous item in sequence (None on first) nextitem: Next item in sequence (None on last) Methods: cycle(*values): Return values[index % len(values)] Output: ``` ``` ``` #### Methods `index` 0 `int` ▼ 1-based iteration count. property `def index(self) -> int` ##### Returns `int` `index0` 0 `int` ▼ 0-based iteration count. property `def index0(self) -> int` ##### Returns `int` `first` 0 `bool` ▼ True if this is the first iteration. property `def first(self) -> bool` ##### Returns `bool` `last` 0 `bool` ▼ True if this is the last iteration. property `def last(self) -> bool` ##### Returns `bool` `length` 0 `int` ▼ Total number of items in the sequence. property `def length(self) -> int` ##### Returns `int` `revindex` 0 `int` ▼ Reverse 1-based index (counts down to 1). property `def revindex(self) -> int` ##### Returns `int` `revindex0` 0 `int` ▼ Reverse 0-based index (counts down to 0). property `def revindex0(self) -> int` ##### Returns `int` `previtem` 0 `Any` ▼ Previous item in the sequence, or None if first. property `def previtem(self) -> Any` ##### Returns `Any` `nextitem` 0 `Any` ▼ Next item in the sequence, or None if last. property `def nextitem(self) -> Any` ##### Returns `Any` `cycle` 1 `Any` ▼ Cycle through the given values. `def cycle(self, *values: Any) -> Any` ##### Parameters Name Type Description `*values` `—` ##### Returns `Any` Internal Methods 3 ▼ `__init__` 1 ▼ `def __init__(self, items: list[Any]) -> None` ##### Parameters Name Type Description `items` `—` `__iter__` 0 `Any` ▼ Iterate through items, updating index for each. `def __iter__(self) -> Any` ##### Returns `Any` `__repr__` 0 `str` ▼ `def __repr__(self) -> str` ##### Returns `str` `AsyncLoopContext` 13 ▼ Loop iteration metadata for ``{% async for %}`` blocks. Provides index-forward variables only. Siz… Loop iteration metadata for`{% async for %}`blocks. Provides index-forward variables only. Size-dependent variables (`last`, `length`, `revindex`, `revindex0`, `nextitem`) raise`TemplateRuntimeError`because async iterables cannot be pre-materialized without defeating the purpose of lazy streaming. The async for-loop drives iteration externally — this class does not implement`__aiter__`. Instead, `advance(item)`is called at the top of each loop iteration by the compiled code. Properties: ``` index: 1-based iteration count (1, 2, 3, ...) index0: 0-based iteration count (0, 1, 2, ...) first: True on the first iteration previtem: Previous item in sequence (None on first) ``` Methods: ``` cycle(*values): Return values[index % len(values)] advance(item): Update state for current iteration (called by compiled code) ``` Part of RFC: rfc-async-rendering. #### Methods `index` 0 `int` ▼ 1-based iteration count. property `def index(self) -> int` ##### Returns `int` `index0` 0 `int` ▼ 0-based iteration count. property `def index0(self) -> int` ##### Returns `int` `first` 0 `bool` ▼ True if this is the first iteration. property `def first(self) -> bool` ##### Returns `bool` `last` 0 `bool` ▼ Not available in async for-loops. property `def last(self) -> bool` ##### Returns `bool` `length` 0 `int` ▼ Not available in async for-loops. property `def length(self) -> int` ##### Returns `int` `revindex` 0 `int` ▼ Not available in async for-loops. property `def revindex(self) -> int` ##### Returns `int` `revindex0` 0 `int` ▼ Not available in async for-loops. property `def revindex0(self) -> int` ##### Returns `int` `previtem` 0 `Any` ▼ Previous item in the sequence, or None if first. property `def previtem(self) -> Any` ##### Returns `Any` `nextitem` 0 `Any` ▼ Not available in async for-loops. property `def nextitem(self) -> Any` ##### Returns `Any` `advance` 1 ▼ Update loop state for the current iteration. Called by compiled async for-loop… `def advance(self, item: Any) -> None` Update loop state for the current iteration. Called by compiled async for-loop code at the top of each iteration, before the loop body executes. ##### Parameters Name Type Description `item` `—` `cycle` 1 `Any` ▼ Cycle through the given values. `def cycle(self, *values: Any) -> Any` ##### Parameters Name Type Description `*values` `—` ##### Returns `Any` Internal Methods 2 ▼ `__init__` 0 ▼ `def __init__(self) -> None` `__repr__` 0 `str` ▼ `def __repr__(self) -> str` ##### Returns `str` ## Functions `_async_loop_unavailable` 1 `NoReturn` ▼ Raise TemplateRuntimeError for size-dependent loop variables in async for. `def _async_loop_unavailable(name: str) -> NoReturn` ##### Parameters Name Type Description `name` `str` ##### Returns `NoReturn`