using TextGenerator = std::shared_ptr<MatchComputation<std::string>>;
+using AnyGenerator = MatchConsumer<llvm::Any>;
+
// Description of a source-code edit, expressed in terms of an AST node.
// Includes: an ID for the (bound) node, a selector for source related to the
// node, a replacement and, optionally, an explanation for the edit.
RangeSelector TargetRange;
TextGenerator Replacement;
TextGenerator Note;
- llvm::Any Metadata;
+ // Not all transformations will want or need to attach metadata and therefore
+ // should not be required to do so.
+ AnyGenerator Metadata = [](const ast_matchers::MatchFinder::MatchResult &) {
+ return llvm::Any();
+ };
};
/// Lifts a list of `ASTEdit`s into an `EditGenerator`.
/// Removes the source selected by \p S.
ASTEdit remove(RangeSelector S);
-inline ASTEdit withMetadata(ASTEdit edit, llvm::Any Metadata) {
- edit.Metadata = std::move(Metadata);
- return edit;
+// FIXME: If `Metadata` returns an `llvm::Expected<T>` the `AnyGenerator` will
+// construct an `llvm::Expected<llvm::Any>` where no error is present but the
+// `llvm::Any` holds the error. This is unlikely but potentially surprising.
+// Perhaps the `llvm::Expected` should be unwrapped, or perhaps this should be a
+// compile-time error. No solution here is perfect.
+//
+// Note: This function template accepts any type callable with a MatchResult
+// rather than a `std::function` because the return-type needs to be deduced. If
+// it accepted a `std::function<R(MatchResult)>`, lambdas or other callable
+// types would not be able to deduce `R`, and users would be forced to specify
+// explicitly the type they intended to return by wrapping the lambda at the
+// call-site.
+template <typename Callable>
+inline ASTEdit withMetadata(ASTEdit Edit, Callable Metadata) {
+ Edit.Metadata =
+ [Gen = std::move(Metadata)](
+ const ast_matchers::MatchFinder::MatchResult &R) -> llvm::Any {
+ return Gen(R);
+ };
+
+ return Edit;
}
/// The following three functions are a low-level part of the RewriteRule
auto Replacement = E.Replacement->eval(Result);
if (!Replacement)
return Replacement.takeError();
+ auto Metadata = E.Metadata(Result);
+ if (!Metadata)
+ return Metadata.takeError();
transformer::Edit T;
T.Range = *EditRange;
T.Replacement = std::move(*Replacement);
- T.Metadata = E.Metadata;
+ T.Metadata = std::move(*Metadata);
Edits.push_back(std::move(T));
}
return Edits;
}
TEST_F(TransformerTest, WithMetadata) {
+ auto makeMetadata = [](const MatchFinder::MatchResult &R) -> llvm::Any {
+ int N =
+ R.Nodes.getNodeAs<IntegerLiteral>("int")->getValue().getLimitedValue();
+ return N;
+ };
+
std::string Input = R"cc(
int f() {
int x = 5;
)cc";
Transformer T(
- makeRule(declStmt().bind("decl"),
- withMetadata(remove(statement(std::string("decl"))), 17)),
+ makeRule(
+ declStmt(containsDeclaration(0, varDecl(hasInitializer(
+ integerLiteral().bind("int")))))
+ .bind("decl"),
+ withMetadata(remove(statement(std::string("decl"))), makeMetadata)),
consumer());
T.registerMatchers(&MatchFinder);
auto Factory = newFrontendActionFactory(&MatchFinder);
ASSERT_EQ(Changes.size(), 1u);
const llvm::Any &Metadata = Changes[0].getMetadata();
ASSERT_TRUE(llvm::any_isa<int>(Metadata));
- EXPECT_THAT(llvm::any_cast<int>(Metadata), 17);
+ EXPECT_THAT(llvm::any_cast<int>(Metadata), 5);
}
TEST_F(TransformerTest, MultiChange) {