API reference - Class Expression
Notation used in Ruby API documentation
Description: Evaluation of Expressions
- Public constructors
- Public methods
- Public static methods and constants
- Deprecated methods (protected, public, static, non-static and constructors)
- Detailed description
This class allows evaluation of expressions. Expressions are used in many places throughout KLayout and provide computation features for various applications. Having a script language, there is no real use for expressions inside a script client. This class is provided mainly for testing purposes.
An expression is 'compiled' into an Expression object and can be evaluated multiple times.
This class has been introduced in version 0.25.
Public constructors
| new Expression ptr | new | (string expr) | Creates an expression evaluator |
| new Expression ptr | new | (string expr, map<string,variant> variables) | Creates an expression evaluator |
Public methods
| void | _create | Ensures the C++ object is created | ||
| void | _destroy | Explicitly destroys the object | ||
| [const] | bool | _destroyed? | Returns a value indicating whether the object was already destroyed | |
| [const] | bool | _is_const_object? | Returns a value indicating whether the reference is a const reference | |
| void | _manage | Marks the object as managed by the script side. | ||
| void | _unmanage | Marks the object as no longer owned by the script side. | ||
| variant | eval | Evaluates the current expression and returns the result | ||
| void | text= | (string expr) | Sets the given text as the expression. | |
| void | var | (string name, variant value) | Defines a variable with the given name and value |
Public static methods and constants
| variant | eval | (string expr) | A convience function to evaluate the given expression and directly return the result | |
| void | global_var | (string name, variant value) | Defines a global variable with the given name and value |
Deprecated methods (protected, public, static, non-static and constructors)
| void | create | Use of this method is deprecated. Use _create instead | ||
| void | destroy | Use of this method is deprecated. Use _destroy instead | ||
| [const] | bool | destroyed? | Use of this method is deprecated. Use _destroyed? instead | |
| [const] | bool | is_const_object? | Use of this method is deprecated. Use _is_const_object? instead |
Detailed description
_create | Signature: void _create Description: Ensures the C++ object is created Use this method to ensure the C++ object is created, for example to ensure that resources are allocated. Usually C++ objects are created on demand and not necessarily when the script object is created. |
_destroy | Signature: void _destroy Description: Explicitly destroys the object Explicitly destroys the object on C++ side if it was owned by the script interpreter. Subsequent access to this object will throw an exception. If the object is not owned by the script, this method will do nothing. |
_destroyed? | Signature: [const] bool _destroyed? Description: Returns a value indicating whether the object was already destroyed This method returns true, if the object was destroyed, either explicitly or by the C++ side. The latter may happen, if the object is owned by a C++ object which got destroyed itself. |
_is_const_object? | Signature: [const] bool _is_const_object? Description: Returns a value indicating whether the reference is a const reference This method returns true, if self is a const reference. In that case, only const methods may be called on self. |
_manage | Signature: void _manage Description: Marks the object as managed by the script side. After calling this method on an object, the script side will be responsible for the management of the object. This method may be called if an object is returned from a C++ function and the object is known not to be owned by any C++ instance. If necessary, the script side may delete the object if the script's reference is no longer required. Usually it's not required to call this method. It has been introduced in version 0.24. |
_unmanage | Signature: void _unmanage Description: Marks the object as no longer owned by the script side. Calling this method will make this object no longer owned by the script's memory management. Instead, the object must be managed in some other way. Usually this method may be called if it is known that some C++ object holds and manages this object. Technically speaking, this method will turn the script's reference into a weak reference. After the script engine decides to delete the reference, the object itself will still exist. If the object is not managed otherwise, memory leaks will occur. Usually it's not required to call this method. It has been introduced in version 0.24. |
create | Signature: void create Description: Ensures the C++ object is created Use of this method is deprecated. Use _create instead |
destroy | Signature: void destroy Description: Explicitly destroys the object Use of this method is deprecated. Use _destroy instead |
destroyed? | Signature: [const] bool destroyed? Description: Returns a value indicating whether the object was already destroyed Use of this method is deprecated. Use _destroyed? instead |
eval | Signature: variant eval Description: Evaluates the current expression and returns the result Python specific notes: |
Signature: [static] variant eval (string expr) Description: A convience function to evaluate the given expression and directly return the result This is a static method that does not require instantiation of the expression object first. Python specific notes: | |
global_var | Signature: [static] void global_var (string name,variant value) Description: Defines a global variable with the given name and value |
is_const_object? | Signature: [const] bool is_const_object? Description: Returns a value indicating whether the reference is a const reference Use of this method is deprecated. Use _is_const_object? instead |
new | Signature: [static] new Expression ptr new (string expr) Description: Creates an expression evaluator Python specific notes: |
Signature: [static] new Expression ptr new (string expr,map<string,variant> variables) Description: Creates an expression evaluator This version of the constructor takes a hash of variables available to the expressions. Python specific notes: | |
text= | Signature: void text= (string expr) Description: Sets the given text as the expression. Python specific notes: |
var | Signature: void var (string name,variant value) Description: Defines a variable with the given name and value |