private Expression rewriteExpression(Expression expression, Predicate<Symbol> symbolScope, boolean allowFullReplacement) { Iterable<Expression> subExpressions = SubExpressionExtractor.extract(expression); if (!allowFullReplacement) { subExpressions = filter(subExpressions, not(equalTo(expression))); } ImmutableMap.Builder<Expression, Expression> expressionRemap = ImmutableMap.builder(); for (Expression subExpression : subExpressions) { Expression canonical = getScopedCanonical(subExpression, symbolScope); if (canonical != null) { expressionRemap.put(subExpression, canonical); } } // Perform a naive single-pass traversal to try to rewrite non-compliant portions of the tree. Prefers to replace // larger subtrees over smaller subtrees // TODO: this rewrite can probably be made more sophisticated Expression rewritten = ExpressionTreeRewriter.rewriteWith(new ExpressionNodeInliner(expressionRemap.build()), expression); if (!symbolToExpressionPredicate(symbolScope).apply(rewritten)) { // If the rewritten is still not compliant with the symbol scope, just give up return null; } return rewritten; }
@Test public void testEqualityGeneration() { EqualityInference.Builder builder = new EqualityInference.Builder(); builder.addEquality(nameReference("a1"), add("b", "c")); // a1 = b + c builder.addEquality(nameReference("e1"), add("b", "d")); // e1 = b + d addEquality("c", "d", builder); EqualityInference inference = builder.build(); Expression scopedCanonical = inference.getScopedCanonical(nameReference("e1"), symbolBeginsWith("a")); assertEquals(scopedCanonical, nameReference("a1")); }
inference.getScopedCanonical(nameReference("a2"), matchesSymbols("c2", "d2")), inference.getScopedCanonical(nameReference("b2"), matchesSymbols("c2", "d2"))); Expression canonical = inference.getScopedCanonical(nameReference("a2"), matchesSymbols("c2", "d2"));
private Expression rewriteExpression(Expression expression, Predicate<Symbol> symbolScope, boolean allowFullReplacement) { Iterable<Expression> subExpressions = SubExpressionExtractor.extract(expression); if (!allowFullReplacement) { subExpressions = filter(subExpressions, not(equalTo(expression))); } ImmutableMap.Builder<Expression, Expression> expressionRemap = ImmutableMap.builder(); for (Expression subExpression : subExpressions) { Expression canonical = getScopedCanonical(subExpression, symbolScope); if (canonical != null) { expressionRemap.put(subExpression, canonical); } } // Perform a naive single-pass traversal to try to rewrite non-compliant portions of the tree. Prefers to replace // larger subtrees over smaller subtrees // TODO: this rewrite can probably be made more sophisticated Expression rewritten = ExpressionTreeRewriter.rewriteWith(new ExpressionNodeInliner(expressionRemap.build()), expression); if (!symbolToExpressionPredicate(symbolScope).apply(rewritten)) { // If the rewritten is still not compliant with the symbol scope, just give up return null; } return rewritten; }
@Test public void testEqualityGeneration() throws Exception { EqualityInference.Builder builder = new EqualityInference.Builder(); builder.addEquality(nameReference("a1"), add("b", "c")); // a1 = b + c builder.addEquality(nameReference("e1"), add("b", "d")); // e1 = b + d addEquality("c", "d", builder); EqualityInference inference = builder.build(); Expression scopedCanonical = inference.getScopedCanonical(nameReference("e1"), symbolBeginsWith("a")); assertEquals(scopedCanonical, nameReference("a1")); }
inference.getScopedCanonical(nameReference("a2"), matchesSymbols("c2", "d2")), inference.getScopedCanonical(nameReference("b2"), matchesSymbols("c2", "d2"))); Expression canonical = inference.getScopedCanonical(nameReference("a2"), matchesSymbols("c2", "d2"));