Tuple swizzling, concat, comparison and `countof`. (#4856)

* Tuple swizzling and element access.

* Update proposal status.

* Cleanup.

* Fix merrge error.

* Address review.

1 files changed, 42 insertions, 0 deletions

diff --git a/source/slang/slang-language-server.cpp b/source/slang/slang-language-server.cpp
index 81c7d24cf..9588e7284 100644
--- a/source/slang/slang-language-server.cpp
+++ b/source/slang/slang-language-server.cpp
@@ -701,6 +701,40 @@ SlangResult LanguageServer::hover(
             }
             fillLoc(expr->loc);
         }
+        else if (auto swizzleExpr = as<SwizzleExpr>(expr))
+        {
+            if (expr->type && swizzleExpr->base && swizzleExpr->base->type)
+            {
+                bool isTupleType = as<TupleType>(swizzleExpr->base->type) != nullptr;
+                sb << "```\n";
+                swizzleExpr->type->toText(sb);
+                sb << " ";
+                swizzleExpr->base->type->toText(sb);
+                sb << ".";
+                for (auto index : swizzleExpr->elementIndices)
+                {
+                    if (isTupleType || index > 4)
+                        sb << "_" << index;
+                    else
+                        sb << "xyzw"[index];
+                }
+                sb << "\n```\n";
+                fillLoc(expr->loc);
+            }
+        }
+        else if (auto countOfExpr = as<CountOfExpr>(expr))
+        {
+            if (countOfExpr->sizedType)
+            {
+                if (auto foldedVal = as<ConstantIntVal>(CountOfIntVal::tryFoldOrNull(version->linkage->getASTBuilder(), expr->type.type, countOfExpr->sizedType)))
+                {
+                    sb << "```\n" << "countof(";
+                    countOfExpr->sizedType->toText(sb);
+                    sb << ") = " << foldedVal->getValue() << "\n```\n";
+                    fillLoc(expr->loc);
+                }
+            }
+        }
         if (const auto higherOrderExpr = as<HigherOrderInvokeExpr>(expr))
         {
             String documentation;
@@ -740,6 +774,14 @@ SlangResult LanguageServer::hover(
     {
         fillExprHoverInfo(thisExprExpr);
     }
+    else if (auto countOfExpr = as<CountOfExpr>(leafNode))
+    {
+        fillExprHoverInfo(countOfExpr);
+    }
+    else if (auto swizzleExpr = as<SwizzleExpr>(leafNode))
+    {
+        fillExprHoverInfo(swizzleExpr);
+    }
     else if (auto importDecl = as<ImportDecl>(leafNode))
     {
         auto moduleLoc = getModuleLoc(version->linkage->getSourceManager(), importDecl->importedModuleDecl);