[Lldb-commits] [lldb] [lldb] Add ternary conditional operator to DIL (PR #211344)

[Ilia Kuklin via lldb-commits]

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@@ -1578,4 +1578,37 @@ llvm::Expected<lldb::ValueObjectSP> Interpreter::Visit(const CastNode &node) {
                                               node.GetLocation());
 }
 
+llvm::Expected<lldb::ValueObjectSP>
+Interpreter::Visit(const ConditionalNode &node) {
+  auto cond_or_err = EvaluateAndDereference(node.GetCondition());
+  if (!cond_or_err)
+    return cond_or_err;
+  lldb::ValueObjectSP condition = *cond_or_err;
+
+  CompilerType cond_type = condition->GetCompilerType();
+  if (!cond_type.IsContextuallyConvertibleToBool()) {
+    std::string errMsg = llvm::formatv(
+        "value of type {0} is not contextually convertible to 'bool'",
+        cond_type.TypeDescription());
+    return llvm::make_error<DILDiagnosticError>(m_expr, errMsg,
+                                                node.GetLocation());
+  }
+  // Note: Unlike C++, DIL evaluates only the operand chosen by the condition,
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kuilpd wrote:

> Thank you @kuilpd for the work that you are doing on DIL. I have been attempting to find the time to contribute for several months, but have not been able to get things at `$DAYJOB` under control. I hope that my minor amount of feedback on this PR makes your life a little easier. Thank you, again, for your great work on DIL!

No problem :) We already have plans and WIP implementation of further DIL features, so code review on PRs would be welcome.
 
> What you state about evaluation of only one of the conditional expression "arms" in DIL is true in C++, too: ["Only one of the second and third expressions is evaluated."](https://eel.is/c++draft/expr.cond#1.sentence-4). It seems like the real differentiator in the semantics is the fact that the types of the expressions in the arms is not checked in DIL but is checked in C++?

Yes, the only difference compared to C++ is that it doesn't check the types of the "arms". I've been told in another PR that comparing to C++ can make it confusing, so I'll remove it here as well.

https://github.com/llvm/llvm-project/pull/211344