Expression¶
Inherits: RefCounted < Object
A class that stores an expression you can execute.
Description¶
An expression can be made of any arithmetic operation, built-in math function call, method call of a passed instance, or built-in type construction call.
An example expression text using the built-in math functions could be sqrt(pow(3, 2) + pow(4, 2)).
In the following example we use a LineEdit node to write our expression and show the result.
var expression = Expression.new()
func _ready():
$LineEdit.text_submitted.connect(self._on_text_submitted)
func _on_text_submitted(command):
var error = expression.parse(command)
if error != OK:
print(expression.get_error_text())
return
var result = expression.execute()
if not expression.has_execute_failed():
$LineEdit.text = str(result)
private Expression _expression = new Expression();
public override void _Ready()
{
GetNode<LineEdit>("LineEdit").TextSubmitted += OnTextEntered;
}
private void OnTextEntered(string command)
{
Error error = _expression.Parse(command);
if (error != Error.Ok)
{
GD.Print(_expression.GetErrorText());
return;
}
Variant result = _expression.Execute();
if (!_expression.HasExecuteFailed())
{
GetNode<LineEdit>("LineEdit").Text = result.ToString();
}
}
Tutorials¶
Methods¶
execute ( Array inputs=[], Object base_instance=null, bool show_error=true, bool const_calls_only=false ) |
|
get_error_text ( ) const |
|
has_execute_failed ( ) const |
|
parse ( String expression, PackedStringArray input_names=PackedStringArray() ) |
Method Descriptions¶
Variant execute ( Array inputs=[], Object base_instance=null, bool show_error=true, bool const_calls_only=false )
Executes the expression that was previously parsed by parse and returns the result. Before you use the returned object, you should check if the method failed by calling has_execute_failed.
If you defined input variables in parse, you can specify their values in the inputs array, in the same order.
String get_error_text ( ) const
Returns the error text if parse or execute has failed.
bool has_execute_failed ( ) const
Returns true if execute has failed.
Error parse ( String expression, PackedStringArray input_names=PackedStringArray() )
Parses the expression and returns an Error code.
You can optionally specify names of variables that may appear in the expression with input_names, so that you can bind them when it gets executed.