[Parser] Allow any number of foldedinsts in `foldedinsts` (#5965)

Somewhat counterintuitively, the text syntax for a folded `if` allows any number
of folded instructions in the condition position, not just one. Update the
corresponding `foldedinsts` parsing function to parse arbitrary sequences of
folded instructions and add a test.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/parser/input-impl.h b/src/parser/input-impl.h
index 35a39b2f3..7ee358f12 100644
--- a/src/parser/input-impl.h
+++ b/src/parser/input-impl.h
@@ -257,6 +257,16 @@ inline bool ParseInput::takeSExprStart(std::string_view expected) {
   return false;
 }
 
+inline bool ParseInput::peekSExprStart(std::string_view expected) {
+  auto original = lexer;
+  if (!takeLParen()) {
+    return false;
+  }
+  bool ret = takeKeyword(expected);
+  lexer = original;
+  return ret;
+}
+
 inline Index ParseInput::getPos() {
   if (auto t = peek()) {
     return lexer.getIndex() - t->span.size();