rhai-python/example_usage.py

#!/usr/bin/env python3
"""
Example usage of the Rhai Python bindings
"""

import rhai


def main():
    print("=== Basic Rhai Python Bindings Demo ===\n")

    # Quick evaluation
    print("1. Quick evaluation:")
    result = rhai.eval("40 + 2")
    print(f"   rhai.eval('40 + 2') = {result}")
    print()

    # Using the engine directly
    print("2. Using RhaiEngine:")
    engine = rhai.RhaiEngine()

    # Basic arithmetic
    result = engine.eval("10 * 5 + 3")
    print(f"   10 * 5 + 3 = {result}")

    # String operations
    result = engine.eval('"Hello, " + "World!"')
    print(f"   String concatenation: {result}")

    # Boolean operations
    result = engine.eval("true && false")
    print(f"   Boolean operation: {result}")
    print()

    # Variables
    print("3. Variable operations:")
    engine.set_var("x", 42)
    engine.set_var("name", "Rhai")

    result = engine.eval("x * 2")
    print(f"   x = 42, x * 2 = {result}")

    result = engine.eval('"Hello, " + name + "!"')
    print(f"   name = 'Rhai', greeting = {result}")

    # Check variables
    print(f"   Variables in scope: {engine.list_vars()}")
    print(f"   Has variable 'x': {engine.has_var('x')}")
    print(f"   Get variable 'x': {engine.get_var('x')}")
    print()

    # Arrays
    print("4. Array operations:")
    result = engine.eval("[1, 2, 3, 4, 5]")
    print(f"   Array creation: {result}")

    engine.set_var("arr", [10, 20, 30])
    result = engine.eval("arr[1]")
    print(f"   Array indexing arr[1]: {result}")

    result = engine.eval("arr.len()")
    print(f"   Array length: {result}")
    print()

    # Objects/Maps
    print("5. Object/Map operations:")
    engine.set_var("obj", {"name": "test", "value": 123})
    result = engine.eval("obj.name")
    print(f"   Object property access: {result}")

    result = engine.eval('#{a: 1, b: "hello", c: true}')
    print(f"   Object creation: {result}")
    print()

    # Control flow
    print("6. Control flow:")
    result = engine.eval("""
        let x = 10;
        if x > 5 {
            "x is greater than 5"
        } else {
            "x is not greater than 5"
        }
    """)
    print(f"   If statement result: {result}")

    result = engine.eval("""
        let sum = 0;
        for i in 1..6 {
            sum += i;
        }
        sum
    """)
    print(f"   Loop sum 1-5: {result}")
    print()

    # Functions
    print("7. Functions:")
    result = engine.eval("""
        fn double(x) {
            x * 2
        }
        double(21)
    """)
    print(f"   Custom function result: {result}")
    print()

    # Error handling
    print("8. Error handling:")
    try:
        engine.eval("undefined_variable")
    except RuntimeError as e:
        print(f"   Caught error: {e}")

    try:
        engine.compile("invalid syntax {{")
    except RuntimeError as e:
        print(f"   Compilation error: {e}")

    print("\n=== Demo Complete ===")


if __name__ == "__main__":
    main()