Expression

Documentation

Overview

Package Expression provides methods for working with Expression object instances.

Index

• type Advanced
• type Any
• type Instance
  • func New() Instance
  • func (self Instance) AsExpression() Instance
  • func (self Instance) AsObject() [1]gd.Object
  • func (self Instance) AsRefCounted() [1]gd.RefCounted
  • func (self Instance) Execute() any
  • func (self Instance) GetErrorText() string
  • func (self Instance) HasExecuteFailed() bool
  • func (self Instance) Parse(expression string) error
  • func (self *Instance) UnsafePointer() unsafe.Pointer
  • func (self Instance) Virtual(name string) reflect.Value

Types

type Advanced

type Advanced = class

Advanced exposes a 1:1 low-level instance of the class, undocumented, for those who know what they are doing.

type Any

type Any interface {
	gd.IsClass
	AsExpression() Instance
}

type Instance

type Instance [1]gdclass.Expression

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 [code]sqrt(pow(3, 2) + pow(4, 2))[/code]. In the following example we use a [LineEdit] node to write our expression and show the result. [codeblocks] [gdscript] 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)

[/gdscript] [csharp] 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();
    }
}

[/csharp] [/codeblocks]

var Nil Instance

Nil is a nil/null instance of the class. Equivalent to the zero value.

func New

func New() Instance

func (Instance) AsExpression

func (self Instance) AsExpression() Instance

func (Instance) AsObject

func (self Instance) AsObject() [1]gd.Object

func (Instance) AsRefCounted

func (self Instance) AsRefCounted() [1]gd.RefCounted

func (Instance) Execute

func (self Instance) Execute() any

Executes the expression that was previously parsed by [method parse] and returns the result. Before you use the returned object, you should check if the method failed by calling [method has_execute_failed]. If you defined input variables in [method parse], you can specify their values in the inputs array, in the same order.

func (Instance) GetErrorText

func (self Instance) GetErrorText() string

Returns the error text if [method parse] or [method execute] has failed.

func (Instance) HasExecuteFailed

func (self Instance) HasExecuteFailed() bool

Returns [code]true[/code] if [method execute] has failed.

func (Instance) Parse

func (self Instance) Parse(expression string) error

Parses the expression and returns an [enum Error] code. You can optionally specify names of variables that may appear in the expression with [param input_names], so that you can bind them when it gets executed.

func (*Instance) UnsafePointer

func (self *Instance) UnsafePointer() unsafe.Pointer

func (Instance) Virtual

func (self Instance) Virtual(name string) reflect.Value