TradingCharts

Declaration Statements

Every script contains exactly one declaration call. It identifies the kind of script and fixes properties that cannot change during a run.

indicator()

indicator(title, shorttitle, overlay, format, precision, scale,
          max_bars_back, timeframe, timeframe_gaps, explicit_plot_zorder,
          max_lines_count, max_labels_count, max_boxes_count,
          max_polylines_count, dynamic_requests, behind_chart)
Parameter Type Default Meaning
title const string required Appears in the chart legend and the publish-to-marketplace flow.
shorttitle const string title Used when space is tight (legend chip).
overlay const bool false true renders on the price pane; false opens a separate pane.
format const format.inherit Default label format for plots. format.price, format.volume, format.percent, format.mintick.
precision const int – Default decimal places for plot labels. Overridden per plot().
scale const scale.right scale.left, scale.right, scale.none (no own axis).
max_bars_back const int – Accepted; the runtime always keeps the full loaded history (5,000 bars), so this is a no-op.
timeframe const string "" Forces the script to compute at this timeframe. See Timeframes.
timeframe_gaps const bool true When timeframe= is set, fill gaps between upstream bars with the previous value.
explicit_plot_zorder const bool false Honored implicitly — plots always draw in declaration order.
max_lines_count const int 500 Cap on live line.new() objects; the oldest is dropped silently beyond it. Range 1–500.
max_labels_count const int 500 Cap on live label.new() objects. Range 1–500.
max_boxes_count const int 500 Cap on live box.new() objects. Range 1–500.
max_polylines_count const int 100 Cap on live polyline.new() objects. Range 1–100.
dynamic_requests const bool true Enables request.* calls whose arguments vary per bar.
behind_chart const bool false true renders this indicator behind the price series. 
//@version=1
indicator("Smoothed RSI", "sRSI", overlay=false, precision=2, max_labels_count=200)

strategy()

A strategy is an indicator that can place orders:

strategy(title, shorttitle, overlay, format, precision, scale,
         pyramiding, calc_on_order_fills, calc_on_every_tick,
         max_bars_back, process_orders_on_close, close_entries_rule,
         slippage, commission_type, commission_value,
         default_qty_type, default_qty_value, initial_capital,
         currency, use_bar_magnifier, fill_orders_on_standard_ohlc,
         calc_on_every_history_tick, margin_long, margin_short,
         max_lines_count, max_labels_count, max_boxes_count,
         max_polylines_count)

The visual-related parameters mirror indicator(). Strategy-specific parameters:

Parameter Type / values Default Meaning
pyramiding const int 1 Max simultaneous same-direction entries.
slippage const int (ticks) 0 Points worsened on every market/stop fill.
commission_type strategy.commission.percent / cash_per_contract / cash_per_order percent How commission_value is interpreted.
commission_value const float 0 Rate for the chosen model.
default_qty_type strategy.fixed / strategy.cash / strategy.percent_of_equity fixed How default_qty_value sizes an entry when qty= is omitted.
default_qty_value const float 1 Size in the chosen units.
initial_capital const float 100000 Starting equity for the backtester.
currency const ignored Accepted for compatibility; backtest reports in the symbol's currency.
process_orders_on_close const bool false false queues market orders to fill at the next bar's open (platform default); true fills at the signal bar's close.
calc_on_every_tick const bool false Recalculate on every live price update of the forming bar (orders can fill intrabar), not only at bar close. Historical bars still calculate once per bar unless calc_on_every_history_tick is set.
calc_on_every_history_tick const bool false ChartScript extension: replay historical bars tick-by-tick as well (bar OHLC path, or lower-timeframe bars with use_bar_magnifier) so backtests match the live every-tick behaviour. Slower.
calc_on_order_fills const bool false After an order fills, run the script once more on the same bar so logic reading strategy.position_size reacts immediately.
use_bar_magnifier const bool false Resolve limit / stop / trailing fills against lower-timeframe bars inside each chart bar instead of the assumed OHLC path. The backtester uses the finest timeframe available and falls back to coarser ones; the report lists the tiers used.
fill_orders_on_standard_ohlc const bool false On Heikin Ashi, Renko and other non-standard charts, fill at the real OHLC prices rather than the synthetic bar's.
margin_long / margin_short const float (%) 100 Percent of a position's value that equity must cover (100 = no leverage, 50 = 2×). Entries that cannot be funded are rejected; a margin call liquidates part of the position. The report shows margin calls and the smallest account size that avoids them.
close_entries_rule "FIFO" / "ANY" FIFO Which entry a partial strategy.close / strategy.exit reduces first.
risk_free_rate, backtest_fill_limits_assumption const – Accepted for compatibility. 
//@version=1
strategy("SMA cross", overlay=true,
         initial_capital=100000,
         default_qty_type=strategy.cash,
         default_qty_value=10000,
         commission_type=strategy.commission.percent, commission_value=0.05,
         slippage=1, process_orders_on_close=false)

See Strategies for the full picture, including strategy.risk.*.

library()

library(title, overlay, dynamic_requests)
Parameter Type Default Meaning
title const string required The import name. Must match [A-Za-z0-9_]+ because it rides the import path (owner/Name/version).
overlay const bool false Advisory only; a library has no plots of its own.
dynamic_requests const bool true Allow request.* calls inside exported functions.

A library must export at least one function, type, or enum:

//@version=1
library("MyMa")

export smooth(float source, int length) =>
    ta.ema(source, length)

See Libraries for publishing and importing.

Property restrictions

  • Every argument to a declaration statement must be a const value — a literal, a color.*/shape.*/strategy.* member, or a value computed only from other const operands.
  • No input.*() call may feed a declaration — the dialog does not exist yet when the declaration runs.
  • Only one declaration statement is allowed per script; the compiler rejects a second as "Script already declared".

See also