LabelOffsetExpression

INCLUDE FILE

#include "Expression/LabelOffsetExpression.h"

class LabelOffsetExpression

Represents a label expression, which refers to a label in an object.

This is the Expression entered into the environment for a label definition. It refers back to the defining BodyElement, which is used to compute the label's value.

DEFINITION

            class LabelOffsetExpression;
        

constructor LabelOffsetExpression

DEFINITION

LabelOffsetExpression	(	const Location & location,
		Symbol entity_name,
		Symbol label_name,
		size_t unnamed_label_index,
		std::shared_ptr< LabelBody > body	);

PARAMETER	DESCRIPTION
`location`
`entity_name`
`label_name`
`unnamed_label_index`
`body`

destructor ~LabelOffsetExpressionvirtual

DEFINITION

virtual ~LabelOffsetExpression

(

);

method bodyconst

DEFINITION

std::shared_ptr< LabelBody > body

(

) const;

RETURNS	DESCRIPTION
`std::shared_ptr< LabelBody >`

method createstatic

DEFINITION

static Expression create	(	const Location & location,
		Symbol entity_name,
		Symbol label_name,
		std::shared_ptr< LabelBody > body	);

PARAMETER	DESCRIPTION
`location`
`entity_name`
`label_name`
`body`

RETURNS	DESCRIPTION
`Expression`

method createstatic

DEFINITION

static Expression create	(	const Location & location,
		Symbol entity_name,
		size_t unnamed_label_index,
		std::shared_ptr< LabelBody > body	);

PARAMETER	DESCRIPTION
`location`
`entity_name`
`unnamed_label_index`
`body`

RETURNS	DESCRIPTION
`Expression`

method entityconst

DEFINITION

Symbol entity

(

) const;

RETURNS	DESCRIPTION
`Symbol`

method evaluatevirtual protected

Evaluate the expression in the given context.

The default implementation calls evaluate() on all sub-expressions using traverse(), and then calls evaluate_process().

Errors during evaluation should either be reported via DiagnosticOutput and result in the expression being marked as invalid, or an exception should be thrown.

DEFINITION

virtual std::optional< Expression > evaluate

(

const EvaluationContext & context

);

PARAMETER	DESCRIPTION
`context`	The evaluation context.

RETURNS	DESCRIPTION
`std::optional< Expression >`	The Expression to replace this expression with, {} if no replacement is needed.

method has_valueconst virtual

Check if the value of the expression is known.

The default implementation returns true if value() returns a value, false otherwise. If the value is expensive to compute, subclasses may override this method to provide a more efficient implementation.

DEFINITION

virtual bool has_value

(

) const;

RETURNS	DESCRIPTION
`bool`	`true` if the value is known, `false` otherwise.

method labelconst

DEFINITION

Symbol label

(

) const;

RETURNS	DESCRIPTION
`Symbol`

method maximum_valueconst virtual

Get the minimum possible value of the expression.

The default implementation returns the value of the expression if it is known, or {} otherwise. Subclasses should override this method if they can determine a minimum value without knowing the exact value of the expression.

DEFINITION

virtual std::optional< Value > maximum_value

(

) const;

RETURNS	DESCRIPTION
`std::optional< Value >`	The minimum possible value of the expression. if it can be determined, {} otherwise.

method minimum_valueconst virtual

Get the maximum possible value of the expression.

The default implementation returns the value of the expression if it is known, or {} otherwise. Subclasses should override this method if they can determine a maximum value without knowing the exact value of the expression.

DEFINITION

virtual std::optional< Value > minimum_value

(

) const;

RETURNS	DESCRIPTION
`std::optional< Value >`	The maximum possible value of the expression if it can be determined, {} otherwise.

method operator==const

Compare two label offset expressions for equality.

DEFINITION

bool operator==

(

const LabelOffsetExpression & other

) const;

PARAMETER	DESCRIPTION
`other`	The other label offset expression to compare with.

RETURNS	DESCRIPTION
`bool`	`true` if both expressions refer to the same body element, `false` otherwise.

method serialize_subconst virtual protected

Serialize the expression to a stream.

This method must be implemented by derived classes.

DEFINITION

virtual void serialize_sub

(

std::ostream & stream

) const;

PARAMETER	DESCRIPTION
`stream`	The stream to serialize to.

method typeconst virtual

Get the type of the expression's value.

The default implementation returns the type of the value of the expression if it is known, or {} otherwise. Subclasses should override this method if they can determine the type of the expression without knowing the exact value of the expression.

DEFINITION

virtual std::optional< Value::Type > type

(

) const;

RETURNS	DESCRIPTION
`std::optional< Value::Type >`	The type of the expression's value if it can be determined, {} otherwise.

method unnamed_indexconst

DEFINITION

size_t unnamed_index

(

) const;

RETURNS	DESCRIPTION
`size_t`

method valueconst virtual

Get the value of the expression if it is known.

Subclasses should override this method. The default implementation returns {}.

DEFINITION

virtual std::optional< Value > value

(

) const;

RETURNS	DESCRIPTION
`std::optional< Value >`	The value of the expression, if it is known.

member body_private

DEFINITION

std::weak_ptr< LabelBody > body_;

member entity_nameprivate

DEFINITION

Symbol entity_name;

member label_nameprivate

DEFINITION

Symbol label_name;

member unnamed_label_indexprivate

DEFINITION

size_t unnamed_label_index;