[clang] [HLSL][RootSignature] Implement Lexing of DescriptorTables (PR #122981)

[Ashley Coleman via cfe-commits]

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@@ -0,0 +1,153 @@
+#include "clang/Parse/ParseHLSLRootSignature.h"
+
+namespace llvm {
+namespace hlsl {
+namespace root_signature {
+
+// Lexer Definitions
+
+static bool IsNumberChar(char C) {
+  // TODO: extend for float support with or without hexadecimal/exponent
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V-FEXrt wrote:

I'm personally not a big fan of untracked TODOs in code. They quickly fall out of context and never get resolved. Would be good to make sure this is tracked as part of an issue if it isn't resolved before merge

https://github.com/llvm/llvm-project/pull/122981