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comparison graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/expression/SLLogicalAndNode.java @ 13836:64c77f0577bb

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More documentation and improvements of Simple Language
author Christian Wimmer <christian.wimmer@oracle.com>
date Thu, 30 Jan 2014 17:53:27 -0800
parents b16ec83edc73
children abe7128ca473
comparison
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13835:67e4e7f56911 13836:64c77f0577bb
24 24
25 import com.oracle.truffle.api.dsl.*; 25 import com.oracle.truffle.api.dsl.*;
26 import com.oracle.truffle.api.nodes.*; 26 import com.oracle.truffle.api.nodes.*;
27 import com.oracle.truffle.sl.nodes.*; 27 import com.oracle.truffle.sl.nodes.*;
28 28
29 /**
30 * This class declares specializations similar to the extensively documented {@link SLAddNode}. It
31 * uses one additional feature of the Truffle DSL: {@link ShortCircuit}.
32 * <p>
33 * Logical operations in SL use short circuit evaluation: if the evaluation of the left operand
34 * already decides the result of the operation, the right operand must not be executed. This is
35 * expressed in the Truffle DSL via a method annotated with {@link ShortCircuit}, which returns
36 * whether a child needs to be executed based on the result of already executed children.
37 */
29 @NodeInfo(shortName = "&&") 38 @NodeInfo(shortName = "&&")
30 @SuppressWarnings("unused") 39 @SuppressWarnings("unused")
31 public abstract class SLLogicalAndNode extends SLBinaryNode { 40 public abstract class SLLogicalAndNode extends SLBinaryNode {
32 41
42 /**
43 * This method is called after the left child was evaluated, but before the right child is
44 * evaluated. The right child is only evaluated when the return value is {code true}.
45 */
33 @ShortCircuit("rightNode") 46 @ShortCircuit("rightNode")
34 protected boolean needsRightNode(boolean left) { 47 protected boolean needsRightNode(boolean left) {
35 return left; 48 return left;
36 } 49 }
37 50
51 /**
52 * Similar to {@link #needsRightNode(boolean)}, but for generic cases where the type of the left
53 * child is not known.
54 */
38 @ShortCircuit("rightNode") 55 @ShortCircuit("rightNode")
39 protected boolean needsRightNode(Object left) { 56 protected boolean needsRightNode(Object left) {
40 return left instanceof Boolean && needsRightNode(((Boolean) left).booleanValue()); 57 return left instanceof Boolean && needsRightNode(((Boolean) left).booleanValue());
41 } 58 }
42 59