[Mlir-commits] [mlir] [MLIR] emitc: Add fmtArgs to verbatim (PR #123294)

[Simon Camphausen]

================
@@ -167,6 +168,64 @@ static LogicalResult verifyInitializationAttribute(Operation *op,
   return success();
 }
 
+/// Parse a format string and return a list of its parts.
+/// A part is either a StringRef that has to be printed as-is, or
+/// a Placeholder which requires printing the next operand of the VerbatimOp.
+/// In the format string, all `{}` are replaced by Placeholders, except if the
+/// `{` is escaped by `{{` - then it doesn't start a placeholder.
+template <class ArgType>
+FailureOr<SmallVector<ReplacementItem>>
+parseFormatString(StringRef toParse, ArgType fmtArgs,
+                  std::optional<llvm::function_ref<mlir::InFlightDiagnostic()>>
+                      emitError = {}) {
+  SmallVector<ReplacementItem> items;
+
+  // If there are not operands, the format string is not interpreted.
+  if (fmtArgs.empty()) {
+    items.push_back(toParse);
+    return items;
+  }
+
+  while (!toParse.empty()) {
+    size_t idx = toParse.find('{');
+    if (idx == StringRef::npos) {
+      // No '{'
+      items.push_back(toParse);
+      break;
+    }
+    if (idx > 0) {
+      // Take all chars excluding the '{'.
+      items.push_back(toParse.take_front(idx));
+      toParse = toParse.drop_front(idx);
+      continue;
+    }
+    if (toParse.size() < 2) {
----------------
simon-camp wrote:

Can we emit an error here instead of allowing an unmatched/unescaped { at the end of the string?

https://github.com/llvm/llvm-project/pull/123294