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Nexus Prop LLC

NexuScript 1.5

Statements and control flow

Variables, decisions, loops and functions.

letDeclares a local variable that may be changed later in its block.ifRuns a block only when a condition is true, with optional elseif and else branches.forRepeats a block over a range of numbers or over the items of an array.breakLeaves the innermost loop at once.continueSkips to the next turn of the innermost loop.returnLeaves a function with a value, or ends this bar's run early in on bar.=Assigns a new value to a variable or an array item.switchRuns the block of the first case that matches a value, or the else block when none does.

let

keywordNexuScript 1.0

Declares a local variable that may be changed later in its block.

Syntax

let name = expression
let name::Type = expression
let (a, b, c) = tuple

Details

A local lives until the end of its block. Assigning to a name that was never declared is an error, so a typo is caught. A let written directly in on bar keeps history: fast[1] is its value on the bar before.

Errors

  • NS200assigning to or reading a name that was never declared

Example

let fast = ta.ema(close, 9)
let (macd_line, signal, hist) = ta.macd(close, 12, 26, 9)
plot("Rising", fast > fast[1] ? 1 : 0)
plot("Histogram", hist, style = "histogram")

See also

conststate=

if

keywordNexuScript 1.0

Runs a block only when a condition is true, with optional elseif and else branches.

Syntax

if condition
    ...
elseif other
    ...
else
    ...
end

Details

Conditions must be Bool; a number is not true or false by itself (write x != 0 or !ismissing(x)). A ta call inside an if whose condition changes from bar to bar is refused, because it would miss bars: work it out before the if.

Errors

  • NS210the condition is not a Bool
  • NS300a function that keeps history inside a branch whose condition changes from bar to bar

Example

let avg = ta.sma(close, 20)
if close > avg
    background(color.fade(color.green, 90))
elseif close < avg
    background(color.fade(color.red, 90))
else
    background(color.none)
end

See also

? :forBool

for

keywordNexuScript 1.0

Repeats a block over a range of numbers or over the items of an array.

Syntax

for i in first:last
for i in first:step:last
for item in array
    ...
end

Details

Ranges include both ends; step may be negative but not 0. Looping over an array works on a copy taken when the loop starts. There is no while: every loop knows how many times it runs. Each step counts toward the step budget of 1,000,000 per bar.

Errors

  • NS300a function that keeps history inside a loop

Example

let total = 0.0
for i in 0:9
    total += coalesce(close[i], close)
end
plot("Average of 10", total / 10)

See also

breakcontinueArray

break

keywordNexuScript 1.0

Leaves the innermost loop at once.

Syntax

break

Example

let found = 0
for i in 1:20
    if high[i] > high
        found = i
        break
    end
end
plot("Bars since a higher high", found)

See also

forcontinue

continue

keywordNexuScript 1.0

Skips to the next turn of the innermost loop.

Syntax

continue

Example

let ups = 0
for i in 0:9
    if close[i] <= open[i]
        continue
    end
    ups += 1
end
plot("Up bars in the last 10", ups)

See also

forbreak

return

keywordNexuScript 1.0

Leaves a function with a value, or ends this bar's run early in on bar.

Syntax

return
return value

Details

A ta call written after a return that only some bars reach is refused, because those bars would skip it.

Example

on bar
    plot("Close", close)
    if bar.index < 20
        return
    end
    marker("20+", position = "below")
end

See also

functionon bar

=

operatorNexuScript 1.0

Assigns a new value to a variable or an array item.

Syntax

name = value
name += value   name -= value   name *= value   name /= value

Details

Works on let locals, state variables and array items (levels[2] = close). Inputs, constants and parameters cannot be assigned. += adds to the variable, and so on.

Missing values

Assigning missing is allowed for numbers.

Example

state count = 0
on bar
    count += 1
    plot("Bars", count)
end

See also

letstate

switch

keywordNexuScript 1.5

Runs the block of the first case that matches a value, or the else block when none does.

Syntax

switch value
case a
    ...
case b, c
    ...
else
    ...
end

Details

The value is a number, text, Bool, colour or enum value, worked out once. Each case lists one or more fixed values of the same type; the first match runs and the others are skipped. When the value and the cases are fixed (an input, a constant), the chosen block is the same on every bar, so functions that keep history may be called inside it, as in an if on an input. In NexuScript 1.4 and earlier switch and case are ordinary names.

Errors

  • NS201a case value appears twice
  • NS210a case value has another type than the switch value
  • NS302a case value changes from bar to bar

Example

nexscript 1.5

indicator "Pick an average", overlay = true

input kind = "EMA", title = "Average", options = ["EMA", "SMA", "WMA"]

on bar
    let avg = missing
    switch kind
    case "EMA"
        avg = ta.ema(close, 20)
    case "SMA"
        avg = ta.sma(close, 20)
    else
        avg = ta.wma(close, 20)
    end
    plot("Average", avg)
end

See also

ifinputenum