PyPScript Syntax Reference

This is the language reference for writing valid .ppc files.

It focuses on the practical syntax you actually use day to day.

Canonical File Shape

#!pyp/1.0
engine: pyp-1.0

import indicators.sma
import functions.cross

strategy "example_name" {
    fast_ma = sma.evaluate(close, 10)
    slow_ma = sma.evaluate(close, 20)

    patterns {
        cross(fast_ma, slow_ma) -> UP(confidence: 0.80)
        default -> HOLD(confidence: 0.95)
    }
}

meta {
    author: "PyP"
    version: "1.0.0"
    description: "Example strategy"
}

config {
    pairs: ["EURUSD"]
    timeframes: ["1m"]
}

Top-Level Blocks

PyPScript files are made of top-level blocks and statements:

• version header
• engine declaration
• imports
• one strategy block
• one meta block
• optional config block

Keep that order stable. It makes scripts easier to read and easier to validate.

Header And Engine

#!pyp/1.0
engine: pyp-1.0

Both lines belong at the top of the file.

Imports

Imports are simple:

import indicators.sma
import indicators.rsi
import functions.above
import functions.below
import functions.cross

Rules:

• each import is one line
• import before the strategy block
• do not import the same module twice
• if you use a function or indicator, import it explicitly

Strategy Declaration

strategy "trend_following" {
    // body
}

The strategy name is a string.

Inside the strategy body you typically declare:

• indicator values
• reusable boolean conditions
• the patterns block

Assignments

Assignments use the standard form:

name = expression

Examples:

fast_ma = sma.evaluate(close, 10)
momentum = rsi.evaluate(close, 14)
trend_up = above(close, fast_ma)

Names should be lowercase with underscores:

fast_ma
slow_ma
trend_up
entry_signal

Avoid:

FastMA
10ma
trend-up

Expressions

Common expressions in PyPScript:

• indicator calls
• function calls
• boolean combinations
• literal numbers and strings

Examples:

sma.evaluate(close, 20)
atr.evaluate(high, low, close, 14)
above(close, trend_ma)
below(momentum, 30)
cross(fast_ma, slow_ma)
above(close, trend_ma) and above(momentum, 55)

Logical Operators

PyPScript uses lowercase logical operators:

• and
• or
• not

Example:

trend_up and momentum_up
trend_up or breakout
not overbought

Use parentheses whenever a condition becomes hard to scan:

(trend_up and momentum_up) or breakout

Patterns Block

The patterns block maps conditions to signals.

patterns {
    condition_a -> UP(confidence: 0.80)
    condition_b -> DOWN(confidence: 0.78)
    default -> HOLD(confidence: 0.95)
}

Rules:

• patterns are evaluated top to bottom
• first match wins
• default should be last
• every signal must include a confidence value

Signals

Valid signal directions:

• UP
• DOWN
• HOLD

Signal form:

UP(confidence: 0.82)
DOWN(confidence: 0.77)
HOLD(confidence: 0.95)

Confidence should be a decimal between 0.0 and 1.0.

Meta Block

meta {
    author: "Stanley Isaac"
    version: "1.2.0"
    description: "Trend continuation strategy"
}

Treat this as the human-facing description of the script.

Good meta values are:

• specific
• versioned
• readable

Config Block

config {
    pairs: ["EURUSD", "GBPUSD"]
    timeframes: ["1m", "5m"]
}

Common config values:

• pairs
• timeframes

Keep config explicit. If a script is only intended for one pair and one timeframe, say so.

Built-In Data Series

Available without import:

• open
• high
• low
• close
• volume
• pair
• timeframe

Example:

range_size = atr.evaluate(high, low, close, 14)
trend_ma = sma.evaluate(close, 50)

Literals

Numbers:

10
20
0.80
0.95

Strings:

"EURUSD"
"1m"
"trend_pullback"

Lists:

["EURUSD", "GBPUSD"]
["1m", "5m"]

Comments

Use // comments.

// Fast trend filter
trend_ma = sma.evaluate(close, 50)

Keep comments focused on intent, not obvious syntax.

Good:

// Only allow longs when the broader trend is already positive
trend_up = above(close, trend_ma)

Weak:

// Assigns SMA to variable
trend_ma = sma.evaluate(close, 50)

Pattern Order Matters

This is valid but wrong:

patterns {
    above(momentum, 50) -> UP(confidence: 0.60)
    above(momentum, 80) -> UP(confidence: 0.90)
    default -> HOLD(confidence: 0.95)
}

Why it is wrong:

• the first rule already catches all values above 80
• the second rule is never reached

Better:

patterns {
    above(momentum, 80) -> UP(confidence: 0.90)
    above(momentum, 50) -> UP(confidence: 0.60)
    default -> HOLD(confidence: 0.95)
}

A Realistic Syntax Example

#!pyp/1.0
engine: pyp-1.0

import indicators.sma
import indicators.rsi
import indicators.atr
import functions.above
import functions.below
import functions.cross

strategy "structured_example" {
    fast_ma = sma.evaluate(close, 20)
    slow_ma = sma.evaluate(close, 50)
    rsi_value = rsi.evaluate(close, 14)
    atr_value = atr.evaluate(high, low, close, 14)

    trend_up = above(fast_ma, slow_ma)
    trend_down = below(fast_ma, slow_ma)
    momentum_up = above(rsi_value, 55)
    momentum_down = below(rsi_value, 45)
    volatility_ok = above(atr_value, 0.0)

    patterns {
        trend_up and momentum_up and cross(close, fast_ma) and volatility_ok -> UP(confidence: 0.84)
        trend_down and momentum_down and cross(fast_ma, close) and volatility_ok -> DOWN(confidence: 0.84)
        default -> HOLD(confidence: 0.96)
    }
}

meta {
    author: "PyP"
    version: "1.0.0"
    description: "Structured trend and momentum example"
}

config {
    pairs: ["EURUSD"]
    timeframes: ["5m"]
}

Syntax Checklist

Before saving a script, verify:

• header is present
• engine line is present
• every used function or indicator is imported
• strategy block exists
• patterns block exists
• default -> HOLD(...) exists
• confidence values are between 0.0 and 1.0
• meta block is present

Related Pages

• Basics
• Variables & Data
• Pattern Matching