OS3xxx Arguments
Every OS3 code, raised when a call is written wrongly where it stands, such as the wrong arguments, a value the parameter does not accept, a per-bar value where a fixed one belongs, or a call that must sit at the top level.
On this page
OS3xxx codes come from the checker, the check stage that runs before the first bar, and every one of them is about a call site: the way a function, a declaration, an input or limits() is called on one line. The script has parsed and its names resolve. What is wrong is the number of arguments, an argument's name, a value the parameter does not accept, or a call written somewhere it cannot be. Nothing has run yet.
A large part of this range protects the study's fixed shape. Before the first bar the chart builds the legend, the pane and its scale, the settings dialog and the list of plots, so everything that feeds them must be known before any data arrives: declaration options, a plot's title and style, every input(), the size and corner of a table. Per-bar values are welcome everywhere else, including a plot's colour.
A script whose calls are all well formed
This study draws a Bollinger-style band on any chart, NIFTY futures or an NSE stock alike, and raises an alert on the bar where the close crosses above the upper edge.
version 1
study("Band breakout", overlay = true, precision = 2)
len = input(20, "Length", min = 2)
mult = input(2.0, "Deviations")
showBand = input(true, "Show the band")
basis = sma(close, len)
dev = mult * stdev(close, len)
// Positional arguments first, named arguments after them.
upper = plot(showBand ? basis + dev : none, "Upper", aqua)
lower = plot(showBand ? basis - dev : none, "Lower", aqua)
plot(basis, "Basis", orange, width = 2)
// fill takes the two plot handles.
fill(upper, lower, color = fade(aqua, 88))
// Per-bar decisions use calls that may sit anywhere.
if crossUp(close, basis + dev)
alert("Close above the upper band", id = "upperBreak")A handle is what plot(), plotCandles(), fill() and level() return: a name for that part of the study, such as upper above, which fill() takes to find its two plots. Where each kind of call may be written:
| Call | May be written | Otherwise |
|---|---|---|
plot, plotCandles, fill, level, table | At the top level only | OS3006 |
input | At the top level only | OS3007 |
limits | Once, as the first statement after the declaration | OS3014 |
signal, alert, background, barColor, cell, print, the draw functions, order calls | Anywhere, including inside if, loops and functions |
Argument lists
Arguments are positional or named. Positional arguments come first, in the order of the signature; named arguments follow, in any order, using the parameter names the reference shows. Each parameter is filled once, and a parameter with a default may be left out.
OS3001 Wrong number of arguments
name takes expected arguments and found were given.
What it means
The call passes more arguments than the function takes. The fix prints the signature, with a ? after each parameter that may be left out, so you can see what the function expects. A common cause is an argument that belongs to a neighbouring call, such as a plot's colour typed inside the indicator it plots: plot(ema(close, 9, aqua), "EMA") gives ema() three arguments. Move it to the call it belongs to. A call with too few arguments is OS3012 instead.
How to fix it
Pass the arguments the signature names: signature.
Before
e = ema(close, 9, 2)After
e = ema(close, 9)OS3002 Unknown named argument
name has no argument called argument.
What it means
Named arguments are matched against the parameter list by exact spelling, and a name that is not on the list would otherwise be silently ignored. The fix lists the names that exist and the closest one to what you wrote. Two frequent causes are British spelling (the parameter is color, not colour) and capitals: names are case sensitive, so colorup is not colorUp.
How to fix it
Use one of names; suggestion is the closest to what was written.
Before
plot(v, "V", colour = aqua)After
plot(v, "V", color = aqua)OS3005 Positional argument after a named one
A positional argument cannot follow a named one.
What it means
Once an argument is named, the arguments after it must be named too, because their position no longer says which parameter they fill. Name the argument, or move it in front of the first named one.
How to fix it
Name this argument too, or move it in front of the first named argument.
Before
b = band(close, len = 20, 3)After
b = band(close, len = 20, mult = 3)OS3013 Argument given twice
argument is given twice at this call site.
What it means
One parameter is filled twice, either by position and then by name, as in ema(close, 9, len = 21), or by the same name written twice. Either way a reader cannot tell which value wins, so the call is refused. Delete the one you did not mean.
How to fix it
Delete one of the two, keeping the value that was meant.
Before
b = band(close, 50, len = 20)After
b = band(close, len = 20)OS3012 A required argument is missing
name requires argument, which has no default.
What it means
A parameter with no default was left out, and there is no value the engine could sensibly invent for it. The usual ones are a title and a source: study() and plot(close) need a title, as in plot(close, "Close"), and an indicator needs its source, as in rsi(close) rather than rsi(). Most indicators need a length as well, as in ema(close, 9); the reference shows which parameters have a default. The fix shows the call with its required arguments.
How to fix it
Pass argument at the call site, as the example shows: example.
Before
study(overlay = true)After
study("Range breakout", overlay = true)OS3011 Argument has the wrong type
name's argument is expected; found was given.
What it means
The argument's type is not the one the parameter takes: text where a number goes, as in ema(close, "9"), a number where a title goes, or a number where a colour goes. Nothing converts on its own. The one allowance is that a plain value may be passed where a series is expected, and it is then read as that same value on every bar, which is why crossUp(close, 22500) works: the level 22500 becomes a series that is 22500 on every bar. Pass a value of the right type, or convert it with text(), toNumber() or toBool().
How to fix it
Convert the value with text(), toNumber() or toBool(), or pass an expression of type expected.
Before
e = ema(close, "9")After
e = ema(close, 9)Values a parameter accepts
OS3004 Argument is not a valid whole number
name's argument must be a whole number range; found was given.
What it means
Some arguments count things, so they must be whole numbers inside a fixed range: a table's rows and columns (1 or more), a cell's row and column (0 or more), a plot's precision (0 to 10) and offset, an rgb() channel (0 to 255), and a loop's step, which must not be 0 because that loop could never finish. When you write the number in the script, the checker tests it and refuses a fraction rather than rounding it, because 2.5 rows is a mistake in the script. Round a value you compute with floor() or round().
Only the arguments listed above are tested before the first bar. A whole number the script computes, such as the length in sma(close, len / 2), is tested when the bar runs instead, as runtime error OS4003. In version 0.5.0 that includes an indicator's length written as a number: sma(close, 14.5) compiles, and the study stops on its first bar with OS4003.
How to fix it
Pass a whole number inside range, and wrap a computed value in floor() or round().
Before
t = table("Summary", 2.5, 2)After
t = table("Summary", 3, 2)OS3008 The value is not valid for this parameter
argument accepts values; found is not one of them.
What it means
The parameter takes one value from a fixed list, because each value selects a different behaviour, and the one written is not on the list. Without this check it would be ignored or replaced by a default without a word. The message lists every accepted value and suggests the closest. Common cases are a plot's style ("line", "step", "histogram" and others), a table's position ("topRight", not "top_right"), and a strategy's qtyType, which is "units", "lots", "cash" or "equityPercent": count NFO futures and options in "lots" and NSE cash shares in "units". A strategy's product is "intraday" or "overnight".
How to fix it
Use one of values; suggestion is the closest to what was written.
Before
strategy("Breakout", qtyType = "shares")After
strategy("Breakout", qtyType = "units")OS3010 Two arguments that cannot both be given
first and second set the same thing two ways.
What it means
Two arguments that set the same thing were both given, and any rule for choosing between them would surprise somebody, so the call is refused. On exit(), a target is either an absolute limit price or a profit distance from the entry, and a stop is either an absolute stop price or a loss distance: give one of each pair, not both. On fill(), a band takes one color for both sides, or colorUp and colorDown for each side, never both kinds. Keep the one you meant.
How to fix it
Keep one of the two: an absolute price or a distance from the entry, one colour for the whole band or a colour for each side, and on a leg described as a future neither right nor strikeOffset.
Before
exit(limit = 105, profit = 5)After
exit(limit = 105)OS3019 A declaration handle in an object argument
name's argument is expected; found is a declaration handle, which has no value at run time.
What it means
plot(), plotCandles(), fill() and level() return a handle: a name for that part of the study, which fill() uses to find two plots. It is fixed before the first bar and is not an object you can change later. cell() and the drawing setters such as draw.setColor() take an object the script created while bars ran: a table, or a line, label, box or polyline.
To change a plot's colour bar by bar, give the plot call a per-bar colour: plot(close, "Close", color = close > open ? lime : red). To draw something you can move or restyle later, create it with draw.line(), draw.box() or draw.label(). This is the case of OS3011 for plot handles.
How to fix it
Pass an object the script created with draw.line(), draw.box() or draw.label(), and change a plot's own appearance through the arguments of the plot call instead.
Before
upper = plot(basis + dev, "Upper", aqua)
draw.setColor(upper, red)After
plot(basis + dev, "Upper", color = close > basis ? lime : red)OS3020 fill needs two declared plots
fill's argument is found; it takes a plot declared by plot() or plotCandles().
What it means
fill() shades the area between two plots already on the chart, so its first two arguments are plot handles: the names you gave two plot() or plotCandles() calls. A bare expression such as basis + dev is not a plot, and neither is a level(). Plot both edges at the top level, name each one, and pass the two names, as the example at the top of this page does. See Fills. This is the case of OS3011 for fill().
How to fix it
Plot both edges at the top level, name each one, and pass the two names to fill().
Before
fill(basis + dev, basis - dev, color = fade(aqua, 88))After
upper = plot(basis + dev, "Upper", aqua)
lower = plot(basis - dev, "Lower", aqua)
fill(upper, lower, color = fade(aqua, 88))Fixed before the first bar
The chart builds a study's legend, pane, axis and settings dialog once, before the first bar runs. Everything that feeds them must be known at that moment: a literal such as 2, arithmetic on literals such as 1 + 1, or an input(), which is read from the settings before the first bar. The reference marks each such parameter as fixed before the first bar in its parameter table.
| Written as | Accepted |
|---|---|
precision = 2 or precision = 1 + 1 | Yes |
precision = input(2, "Decimals") | Yes |
dp = input(2, "Decimals"), then precision = dp | Yes |
var dp = 2, then precision = dp | No, OS3003: a var can change on later bars |
precision = round(close / 1000) | No, OS3003: it depends on the bar |
precision = input(2, "Decimals") + 1 | No. In version 0.5.0 this reports only OS6018; put the arithmetic in the default instead: input(3, "Decimals") |
OS3003 This option must be a constant
option is read once, before the first bar, so it cannot depend on bar data.
What it means
The argument feeds something that is built before the first bar, and the value you wrote can change from bar to bar. This covers every option of study() and strategy(), a plot's title, width and style, a signal's color, at and shape, a table's title, size and corner, and an alert's id, title and frequency. Use a literal, or an input() so the user can change it in the settings dialog. A name assigned from an input works too, as in dp = input(2, "Decimals") followed by precision = dp, but a var does not, because a var can change on later bars. The table above shows each form.
The fix's sample input always uses 2 as its default; write the default that suits the option, such as input(true, "Overlay") for overlay. A plot's color is not on this list, so a colour chosen per bar is fine. In version 0.5.0 the console also shows OS6018 on the same line, with a long technical message; it goes away when this error is fixed.
How to fix it
Use a literal, or make it tunable with an input(): option = input(2, "option").
Before
study("Range", precision = round(close / 1000))After
study("Range", precision = input(2, "precision"))OS3006 This call must be at the top level
name defines part of the study's fixed shape and cannot appear inside construct.
What it means
plot, plotCandles, fill, level and table declare the fixed shape of the study: its columns, bands, horizontal lines and grids. The legend and the settings dialog list them before the first bar, so they cannot sit inside an if, a loop, a switch arm or a function body, where they would exist on some bars and not others. To show a plot on some bars only, keep it at the top level and give it none on the others: plot(trending ? ema20 : none, "EMA 20", aqua). A plot draws a gap wherever its value is none.
The same code covers a drawing or an alert inside the expression of a req.timeframe() or req.symbol() read. That expression is evaluated on the other timeframe's or instrument's bars, where there is no bar of this chart to draw on. Read the value first, then draw or alert with it on the next line.
How to fix it
Move the call to the top level and hide it per bar by passing none: plot(cond ? value: none,...). Inside a request expression, read the value first and draw with it afterwards. A leg is not hidden by passing none: declare it at the top level and decide per bar whether to send it an order.
Before
if trending
plot(ema20, "EMA 20", aqua)After
plot(trending ? ema20 : none, "EMA 20", aqua)OS3007 input() must be at the top level
input() builds one row of the settings dialog, which is read once before the first bar.
What it means
Each input() is one row of the settings dialog, and the dialog exists before any bar runs, so a row cannot appear or vanish with the data, and a saved setting needs a row that is always there. Put every input() at the top level of the file, including the ones used only inside a function or an if, and read its name inside the block. See Inputs.
How to fix it
Move the input() to the top level and use the name it assigns inside the block.
Before
if useBand
len = input(20, "Length")After
len = input(20, "Length")
b = sma(close, len)
plot(useBand ? b : none, "Band", aqua)OS3009 This option needs another option to be set
option = value requires required.
What it means
Some options only mean something together. An alert with frequency = "everyUpdate" fires on every update of the bar that is still forming, but by default signals, alerts and orders act only on confirmed bars, so on its own that frequency would never have an update to fire on. Add onUnconfirmed = true to the declaration, or use the default frequency, "oncePerBar". See Realtime and confirmation.
How to fix it
Set required in the declaration, or choose a value of option that stands on its own.
Before
study("Ticks")
if close > open
alert("Up", id = "up", frequency = "everyUpdate")After
study("Ticks", onUnconfirmed = true)
if close > open
alert("Up", id = "up", frequency = "everyUpdate")OS3016 range must be a low and a high
range is [low, high]; it takes two numbers and the first must be below the second.
What it means
The range option of a declaration fixes the scale of the study's own pane, and it is written as two numbers in square brackets, the lower first: range = [0, 100] for an oscillator such as RSI. A reversed pair such as [100, 0], a list with one number or two equal numbers leave no scale to draw. A bare number with no brackets, range = 50, is OS3011 instead.
How to fix it
Write two numbers, lowest first: range = [0, 100].
Before
study("RSI", range = [100, 0])After
study("RSI", range = [0, 100])limits()
limits() sets two of the engine's budgets for one script: loops, the number of loop turns it may run on one bar, and history, how many past bars the engine keeps. See Limits.
OS3014 limits() is in the wrong place
limits() appears at most once, immediately after the declaration; this one is at line line.
What it means
limits() is the first statement after the study() or strategy() declaration (blank lines and comments may sit between them), and it appears only once, so that anyone reading the file sees its budgets at the top. Move it up, and merge two calls into one: limits(loops = 5_000_000, history = 5000).
How to fix it
Move the limits() line directly under study(...) or strategy(...), and merge two calls into one.
Before
study("Heavy")
len = input(20, "Length")
limits(loops = 50_000_000)After
study("Heavy")
limits(loops = 50_000_000)
len = input(20, "Length")OS3015 limits() takes literal numbers
limits() is read before the first bar, so option must be a literal number.
What it means
The engine sets aside room for these budgets before the first bar runs, so each one must be a number written out in full, such as 5_000_000. Even arithmetic on numbers, such as 1000 * 1000, is refused, and an input() is refused too, because a budget a settings dialog could change is a budget nobody can see by reading the script.
How to fix it
Write the number: limits(loops = 50_000_000).
Before
limits(loops = maxBars * 1000)After
limits(loops = 50_000_000)Names and settings keys
Plots, levels, inputs and alerts are identified by name. The legend and the settings dialog label rows with them, saved settings are stored under them, and an alert subscription is kept under the alert's id. That is why each must be unique, and why an input needs a name or a title to be stored under. The rule is per kind: a plot and a level may share a title, but two plots may not.
OS3017 Two of these share a name
kind names must be unique in a file; name is also used at line line.
What it means
Two plots, two levels, two inputs or two alerts in one file share a name. Their rows in the legend and the settings dialog would be indistinguishable, and one would overwrite the other's saved settings. Two alerts with one id would leave a subscription attached to whichever of the two was kept. Rename one of them so each name appears once, such as "EMA fast" and "EMA slow".
How to fix it
Rename one of them so each name appears once.
Before
plot(fast, "EMA", aqua)
plot(slow, "EMA", orange)After
plot(fast, "EMA fast", aqua)
plot(slow, "EMA slow", orange)OS3018 The default is not in the options list
This input's default default is not one of options values.
What it means
An input with options is a dropdown, and its default is the entry selected when the settings dialog opens, so the default must be one of the options. Check the spelling and the capitals: "Fast" and "fast" are different strings. The options themselves are strings.
How to fix it
Add default to options, or make the default one of the listed values.
Before
mode = input("medium", "Mode", options = ["fast", "slow"])After
mode = input("fast", "Mode", options = ["fast", "slow"])OS3021 An input written in place has no title
An input() assigned to no name is named by its title, and this one has no title written as a string literal.
What it means
An input written directly inside another call, rather than assigned to a name, has no name to store the user's setting under, so its title is used as its key as well as its label. That title must be a string written in quotes inside the call; a name holding a string does not count. Give it one, input(2, "Precision"), or assign the input to a name first and use the name.
How to fix it
Give it a title written as a string literal: input(2, "Precision").
Before
study("Range", precision = input(2))After
study("Range", precision = input(2, "Precision"))OS3024 An input written in place has an empty title
An input() assigned to no name is named by its title, and this one's title is empty.
What it means
This is OS3021 with a title that is present but empty. An empty string can neither label the row nor serve as its key, and a second input written the same way would share that empty key. Give the title something to say. An input assigned to a name may have an empty title, because the name labels the row, so len = input(14, "") compiles.
How to fix it
Give the title something to say: input(2, "Precision").
Before
study("Range", precision = input(2, ""))After
study("Range", precision = input(2, "Precision"))OS3022 Two inputs share a settings key
This input is keyed by its title name, which is already the name of the input at line line.
What it means
An input assigned to a name is stored under that name, and an input written in place is stored under its title. Here the title of one input spells the name of another, so both rows would share one stored setting and nothing would decide which row gets it. Give the in-place input a title of its own, or rename the other input. This is the case of OS3017 for settings keys.
How to fix it
Give this one a title of its own, or rename the input at line line.
Before
width = input(2, "Width")
plot(close + width * input(3, "width"), "Band", aqua)After
width = input(2, "Width")
plot(close + width * input(3, "Multiplier"), "Band", aqua)Orders
OS3023 An order names a leg this file does not declare
name was given a argument, and this file declares none.
What it means
An order call was given a leg argument, but the file declares no legs. A strategy with no legs trades exactly one instrument, the one on the chart, and every order acts on it, so a leg name there names nothing. Remove the leg argument. Declaring legs with leg.fixed() or leg.relative() for multi-leg option positions is planned and not available in version 0.5.0; see Legs and books.
Related. Reading an error, Declarations, Inputs, Plots, Fills, Limits, OS2xxx Names and types, OS4xxx Runtime errors
How to fix it
Leave argument out. A file that declares no leg has exactly one, and every order acts on it.
Before
if pos.isFlat
buy(qty = 1, leg = "hedge")
else
close()After
if pos.isFlat
buy(qty = 1)
else
close()