Copyright (c) 2000, 2013 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.debug.core.model;


An expression is a snippet of code that can be evaluated
to produce a value. When and how an expression is evaluated
is implementation specific. The context/binding required to
evaluate an expression varies by debug model, and by
user intent. Furthermore, an expression may need to be evaluated
at a specific location in a program (for example, at a
breakpoint/line where certain variables referenced in the
expression are visible/allocated). A user may want to
evaluate an expression once to produce a value that can
be inspected iteratively, or they may wish to evaluate an
expression iteratively producing new values each time
(i.e. as in a watch list).

Clients are intended to implement this interface.

Since:
2.0/**
 * An expression is a snippet of code that can be evaluated
 * to produce a value. When and how an expression is evaluated
 * is implementation specific. The context/binding required to
 * evaluate an expression varies by debug model, and by
 * user intent. Furthermore, an expression may need to be evaluated
 * at a specific location in a program (for example, at a
 * breakpoint/line where certain variables referenced in the
 * expression are visible/allocated). A user may want to
 * evaluate an expression once to produce a value that can
 * be inspected iteratively, or they may wish to evaluate an
 * expression iteratively producing new values each time
 * (i.e. as in a watch list).
 * <p>
 * Clients are intended to implement this interface.
 * </p>
 * @since 2.0
 */
public interface IExpression extends IDebugElement {

	
Returns this expression's snippet of code.
Returns:
the expression/**
	 * Returns this expression's snippet of code.
	 *
	 * @return the expression
	 */
	String getExpressionText();

	
Returns the current value of this expression or
null if this expression does not
currently have a value.
Returns:
value or null/**
	 * Returns the current value of this expression or
	 * <code>null</code> if this expression does not
	 * currently have a value.
	 *
	 * @return value or <code>null</code>
	 */
	IValue getValue();

	
Returns the debug target this expression is associated
with, or null if this expression is not
associated with a debug target.
See Also:
IDebugElement.getDebugTarget()
Returns:
debug target or null/**
	 * Returns the debug target this expression is associated
	 * with, or <code>null</code> if this expression is not
	 * associated with a debug target.
	 *
	 * @return debug target or <code>null</code>
	 * @see IDebugElement#getDebugTarget()
	 */
	@Override IDebugTarget getDebugTarget();

	
Notifies this expression that it has been removed
from the expression manager. Any required clean up
is be performed such that this expression can be
garbage collected.
/**
	 * Notifies this expression that it has been removed
	 * from the expression manager. Any required clean up
	 * is be performed such that this expression can be
	 * garbage collected.
	 */
	void dispose();
}