com.oracle.truffle.api.nodes

Interface RepeatingNode

All Superinterfaces:

NodeInterface

public interface RepeatingNode
extends NodeInterface

A node that is repeatedly invoked as part of a Truffle loop control structure. Repeating nodes must extend Node or a subclass of Node. Repeating nodes are intended to be implemented by guest language implementations. For a full usage example please see LoopNode. Note: The result of shouldContinue( executeRepeatingWithValue()) is automatically profiled by the loop node, so the repeating node should not use a loop condition profile.

Since:

0.8 or earlier

See Also:

LoopNode, TruffleRuntime.createLoopNode(RepeatingNode)

Field Summary

Fields

Modifier and Type	Field and Description
static Object	BREAK_LOOP_STATUS A value indicating that the loop should not be repeated.
static Object	CONTINUE_LOOP_STATUS A value indicating that the loop should be repeated.

Method Summary

Modifier and Type	Method and Description
boolean	executeRepeating(VirtualFrame frame) Repeatedly invoked by a loop node implementation until the method returns false or throws an exception.
default Object	executeRepeatingWithValue(VirtualFrame frame) Repeatedly invoked by a loop node implementation, but allows returning a language-specific loop exit status.
default Object	initialLoopStatus() Returns a placeholder loop status used internally before the first iteration.
default boolean	shouldContinue(Object returnValue) Predicate called on values returned by executeRepeatingWithValue().

Field Detail

CONTINUE_LOOP_STATUS

static final Object CONTINUE_LOOP_STATUS

A value indicating that the loop should be repeated.

Since:

19.3

BREAK_LOOP_STATUS

static final Object BREAK_LOOP_STATUS

A value indicating that the loop should not be repeated. Any other value different than CONTINUE_LOOP_STATUS can also be used to indicate that the loop should not be repeated.

Since:

19.3

Method Detail

executeRepeating

boolean executeRepeating(VirtualFrame frame)

Repeatedly invoked by a loop node implementation until the method returns false or throws an exception.

Parameters:

frame - the current execution frame passed through the interpreter

Returns:

true if the method should be executed again to complete the loop and false if it must not.

Since:

0.8 or earlier

executeRepeatingWithValue

default Object executeRepeatingWithValue(VirtualFrame frame)

Repeatedly invoked by a loop node implementation, but allows returning a language-specific loop exit status. Only languages that need to return custom loop statuses should override this method.

Parameters:

frame - the current execution frame passed through the interpreter

Returns:

a value v satisfying shouldContinue(v) == true if the method should be executed again to complete the loop and any other value if it must not.

Since:

19.3

initialLoopStatus

default Object initialLoopStatus()

Returns a placeholder loop status used internally before the first iteration.

Returns:

a value satisfying shouldContinue(initialLoopStatus(v)) == true

Since:

20.3

shouldContinue

default boolean shouldContinue(Object returnValue)

Predicate called on values returned by executeRepeatingWithValue().

Parameters:

returnValue - a value returned by executeRepeatingWithValue()

Returns:

true if the loop should continue executing or false otherwise

Since:

20.3