Dana Language Syntax Reference¶

Dana is a domain-specific language designed for AI-driven automation and reasoning. This document provides a comprehensive reference for Dana's syntax and language features, as supported by the current grammar and runtime.

Dana vs. Python: Quick Comparison¶

Dana's syntax is intentionally similar to Python: indentation, assignments, conditionals, loops, and function calls all look familiar.
Dana requires explicit scope prefixes for variables (e.g., private:x, public:y), unlike Python.
Dana only supports single-line comments with # (no docstrings).
Dana supports f-strings with embedded expressions (e.g., f"Value: {x+1}").
Some advanced Python features (like comprehensions, decorators, or dynamic typing) are not present in Dana.

Basic Syntax¶

Comments¶

# This is a single-line comment

Variables and Scoping¶

Dana has a structured scoping system with four standard scopes: - private: Private to the agent, resource, or tool itself - public: Openly accessible world state (time, weather, etc.) - system: System-related mechanical state with controlled access - local: Local scope for the current execution (implicit in most cases)

Variables must be prefixed with their scope:

private:my_variable = value
public:shared_data = value
system:status = value

For convenience in the REPL environment, variables without a scope prefix are automatically placed in the local scope:

my_variable = value # Equivalent to local:my_variable = value

Basic Data Types¶

Strings: "double quoted" or 'single quoted'
Numbers: 42 or 3.14
Booleans: true or false
Null: null

Statements¶

Assignment¶

private:x = 10
public:message = "Hello"

Conditional Statements¶

if private:x > 5:
 print("x is greater than 5")
else:
 print("x is not greater than 5")

While Loops¶

while private:x < 10:
 print(private:x)
 private:x = private:x + 1

Function Calls¶

system:math.sqrt(16)
public:result = system:math.max(3, 7)
print("Hello, World!")
print(private:x)

Bare Identifiers¶

A bare identifier (just a variable or function name) is allowed as a statement, typically for REPL inspection:

private:x

Expressions¶

Binary Operators¶

Comparison: ==, !=, <, >, <=, >=
Logical: and, or
Arithmetic: +, -, *, /, %

Operator Precedence¶

Parentheses ()
Multiplication/Division/Modulo *, /, %
Addition/Subtraction +, -
Comparison <, >, <=, >=, ==, !=
Logical and, or

Function Calls in Expressions¶

private:y = system:math.sqrt(private:x)

Best Practices¶

Always use explicit scope prefixes for clarity
Use meaningful variable names
Add comments for complex logic
Structure code with clear indentation for blocks

Examples¶

Basic Program with Scoping¶

# Define variables with explicit scopes
private:name = "World"
public:count = 5
system:status = "active"

# Print
print("Hello, " + private:name)
print(public:count)

# Conditional logic
if public:count > 3:
 print("Count is high")
else:
 print("Count is normal")

While Loop Example¶

private:x = 0
while private:x < 3:
 print(private:x)
 private:x = private:x + 1