BaseExpression
Abstract base class for all expressions.
Initialize a BaseExpression with default values.
| BaseExpression | ( | ); |
Initialize a BaseExpression with a specific location.
| BaseExpression | ( | const Location & location | ); |
| PARAMETER | DESCRIPTION |
|---|---|
location |
The location of the expression. |
Destroy the BaseExpression object.
| virtual ~BaseExpression | ( | ); |
Create a deep copy of the expression.
A subclass must override this method if it can occur in a macro or function definition, .repeat body, or instruction encoding.
| virtual Expression clone | ( | const CloneContext & context | ) const; |
| PARAMETER | DESCRIPTION |
|---|---|
context |
| RETURNS | DESCRIPTION |
|---|---|
Expression |
A shared pointer to the cloned expression. |
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.
| 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. |
Process the evaluation of the expression.
This method is called by the default implementation of evaluate() after calling evaluate() on all sub-expressions.
| virtual std::optional< Expression > evaluate_process | ( | const EvaluationContext & context | ); |
| PARAMETER | DESCRIPTION |
|---|---|
context |
The evaluation context. |
| RETURNS | DESCRIPTION |
|---|---|
std::optional< Expression > |
If the expression changed, returns the new expression, otherwise {}. |
Expand function calls in the expression.
The default implementation calls expand_calls() on all sub-expressions using traverse() and returns {}.
If a function call cannot be expanded, either an error should be reported via DiagnosticOutput and the expression marked as invalid, or an exception should be thrown.
| virtual std::optional< Expression > expand_calls | ( | ); |
| RETURNS | DESCRIPTION |
|---|---|
std::optional< Expression > |
The Expression to replace this Expression with, {} if no replacement is needed. |
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.
| virtual bool has_value | ( | ) const; |
| RETURNS | DESCRIPTION |
|---|---|
bool |
|
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.
| 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. |
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.
| 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. |
Resolve all names in the expression.
The default implementation calls resolve() on all sub-expressions using traverse().
If a name cannot be resolved, either an error should be reported via DiagnosticOutput and the expression marked as invalid, or an exception should be thrown.
| virtual void resolve | ( | Scope * scope, | |
| Entity * containing_entity | ); |
| PARAMETER | DESCRIPTION |
|---|---|
scope |
The scope to resolve names in. |
containing_entity |
The entity that contains the expression. |
Serialize the expression to a stream.
| virtual void serialize | ( | std::ostream & stream | ) const; |
| PARAMETER | DESCRIPTION |
|---|---|
stream |
The stream to serialize to. |
Serialize the expression to a stream.
This method must be implemented by derived classes.
| virtual void serialize_sub | ( | std::ostream & stream | ) const | = 0; |
| PARAMETER | DESCRIPTION |
|---|---|
stream |
The stream to serialize to. |
Call a method on all sub-expressions of this expression.
It is used by the default implementations of resolve() and expand_calls(). Unless a subclass has no sub-expressions or overrides both of these methods, it should override traverse().
| virtual void traverse | ( | std::function< void(Expression &)> callable | ); |
| PARAMETER | DESCRIPTION |
|---|---|
callable |
A callable to apply to each sub-expression. |
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.
| 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. |
Get the value of the expression if it is known.
Subclasses should override this method. The default implementation returns {}.
| virtual std::optional< Value > value | ( | ) const; |
| RETURNS | DESCRIPTION |
|---|---|
std::optional< Value > |
The value of the expression, if it is known. |
The location of the expression in the source code.
Indicates whether the expression has been resolved.
Indicates whether the expression is valid.
If an error occurs during evaluation, this flag should be set to false. This allows the expression to be used in further evaluations without causing additional errors.