# Pine Script Transpiler - Limitations

This document describes unsupported and partially supported Pine features in the current transpiler/runtime.

## Unsupported Features

### External `request.*` APIs

Only `request.security` has subset support. The following remain unsupported:

- `request.financial`
- `request.quandl`
- `request.seed`
- `request.economic`
- `request.dividends`
- `request.earnings`
- `request.splits`

### Ticker Namespace Extensions

- `ticker.new`
- `ticker.modify`

### Strategy/Backtesting Runtime

The transpiler targets indicators. Strategy execution is not implemented:

- `strategy.entry`
- `strategy.exit`
- `strategy.close`
- `strategy.order`
- `strategy.cancel`
- `strategy.risk.*`

### Polyline APIs

- `polyline.*` is not implemented.

## Partially Supported Features

### `request.security` (MTF subset)

Current behavior supports practical subset semantics:

- value passthrough for same/lower timeframe requests
- higher-timeframe bucket merge in runtime
- tuple expressions
- `barmerge.gaps_*` and `barmerge.lookahead_*` subset handling
- explicit runtime diagnostics on unsupported fallback modes
  (`__runtimeDiagnostics` on the returned plot array), including
  external symbol and lower-timeframe fallback

Not yet supported:

- external symbol data fetching
- full Pine-equivalent barmerge behavior across all edge cases

### Drawing APIs (runtime-compatible handles, partial direct rendering)

Drawing namespaces are stateful, persist across bars (Pine `var` semantics), and support common method subsets so scripts execute. Direct visual rendering inside the transpiler is intentionally limited — chart-host `CustomIndicator` outputs (plots, palette-backed bg_colorers) cannot draw arbitrary shapes. Anything beyond bg_colorer goes through the host renderer (see [HOST_RENDERING_CONTRACT.md](HOST_RENDERING_CONTRACT.md)).

Direct rendering inside the transpiler:

- **`box.new(..., bgcolor=...)`** — auto-emits a `bg_colorer` plot driven by an 8-slot palette. Session-highlighting scripts (ICT-style killzones, FX sessions) get colored backgrounds with no host work. Palette colors are a fixed rainbow set; slot assignment is first-seen at runtime.

Tracked-but-not-rendered (host renderer must consume `__visualEvents`):

- Box rectangles with borders / inline text
- `line.new` (pivots, separators, opens)
- `label.new` (text annotations)
- `table.new` / `table.cell` (TV CustomIndicators have no native runtime table; renderer must use a DOM overlay)

Supported method subsets:

- `line`: `new`, `delete`, `set_x2`, `set_xy1`, `set_xy2`, `set_color`, `get_x2`, `get_y1`, `get_y2`
- `box`: `new`, `delete`, `set_left`, `set_right`, `set_top`, `set_bottom`, `set_extend`, `set_bgcolor`, `set_border_color`, `set_border_width`, `set_text_color`, `get_left`, `get_right`, `get_top`, `get_bottom`
- `label`: `new`, `delete`, `set_text`, `set_tooltip`, `set_textcolor`, `set_style`, `set_xy`, `set_x`, `set_y`, `get_text`, `get_y`
- `table`: `new`, `cell`, `clear`, `merge_cells`

### Plot/Visual Functions

- `plot`, `plotshape`, `plotchar`, `plotarrow`, `bgcolor`, `fill`, `barcolor`, `hline` are runtime-compatible.
- `plot` / `plotshape` / `plotchar` / `plotarrow` / `hline` render directly through chart-host `CustomIndicator` plot output.
- `plotchar(text = identifier)` resolves through tracked string-literal var definitions and is promoted to the `char` glyph when `char` is empty.
- `bgcolor`, `fill`, `barcolor` are tracked in visual-event artifacts; rendering of those that don't lower to a `bg_colorer` plot remains host responsibility.

### Pine `var` / `varip` inside function bodies

Function-local persistent state is now runtime-backed and call-site scoped:

- `var` inside functions persists across bars and calls.
- `varip` inside functions resets on new bars, while persisting intrabar.
- state keys are isolated per function call-site to match Pine behavior for multi-call scripts.

### Alerts

- `alert()` and `alertcondition()` are runtime no-ops. The transpiler swallows the call without errors or routing. If alerting is required, prefetch the alert condition values via plot outputs and let the host wire its own notification surface.

### Session/Time Semantics

- `session.ismarket`, `session.ispremarket`, `session.ispostmarket`, `time_close`, `time_tradingday` are supported with deterministic runtime helpers.
- Session/timezone semantics are still a compatibility model, not full exchange-engine parity.

## Data Structures

### Maps

Implemented subset:

- `map.new`, `map.put`, `map.put_all`, `map.get`, `map.contains`, `map.remove`, `map.size`, `map.keys`, `map.values`, `map.clear`, `map.copy`

### Matrices

Implemented subset:

- `matrix.new`, `matrix.rows`, `matrix.columns`, `matrix.get`, `matrix.set`, `matrix.add_row`, `matrix.remove_row`

Advanced matrix APIs beyond this subset are not yet implemented.

## Alerts and Logging

- `alertcondition` and `alert` are runtime no-ops for compatibility.
- `log.*` and `runtime.error` are partial/non-parity behaviors.

## Library Imports

- `import "user/lib/1" as Lib` syntax is parsed.
- External library resolution/loading is not implemented.

## Operational Limits

To reduce abuse risk:

- max input size: `1,000,000` characters
- max loop iterations: `10,000`
- max recursion depth: `1,000`

## Recommended Integration Approach

- Treat transpiler outputs as executable indicator logic + visual intent events.
- Handle final rendering and alert routing in the host app.
- For unsupported external data APIs, prefetch data in your app and feed it as inputs.