print function

The print function is used to generate run-time messages. Run-time messages are written to the Compiler Messages tool window while the formula is being executed. This is very useful when debugging your formulas, or when trying new ideas.

To enable run-time messages, the DEBUG symbol has to be defined. See Compiler directives.

The print function basically prints anything you throw at it. It can print expressions of the types complex, float, int, bool, and color. It can also print text and object references. You can use multiple arguments to mix the various types of expressions, and they will all be printed consecutively on the same line.

Examples:

$define DEBUG
print("Hello, world!")                    ; Hello, world!
print("I'm ", 2 * 4, " years old.")       ; I'm 8 years old.
print("This is a color: ", rgb(1, 0, 0))  ; This is a color: (1, 0, 0)
print("The value of pi is ", #pi)         ; The value is pi is 3.14159...
Object obj = new MyClass
print(obj)                                ; MyClass (1)

For object references, the print function prints the actual type of the object and its reference count. See Casting and Memory management.

If you try the example with the value of pi, look at how the number of decimals changes when you adjust the Additional Precision setting in the Formula tab of the Layer Properties tool window.

The print function does not return a value, and can only be used as a statement, not as an expression. See Expressions.

See Also
Debugging