From 196e49c1f8bd58ab9ce81843c10d452284ca7569 Mon Sep 17 00:00:00 2001 From: Nat Goodspeed Date: Mon, 19 Dec 2022 17:27:36 -0500 Subject: DRTVWR-558: Add unit test for VAPPLY(). Add to apply_test.cpp a collect() function that incrementally accumulates an arbitrary number of arguments into a std::vector. Construct a std::array to pass it, using VAPPLY(). Clarify in header comments that LL::apply() can't call a variadic function with arguments of dynamic size: std::vector or LLSD. The compiler can deduce how many arguments to pass to a function with a fixed argument list; it can deduce how many arguments to pass to a variadic function with a fixed number of arguments. But it can't compile a call to a variadic function with an arguments data structure whose size can vary at runtime. (cherry picked from commit ceed33396266b123896f7cfb9b90abdf240e1eec) --- indra/llcommon/llsdutil.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'indra/llcommon/llsdutil.h') diff --git a/indra/llcommon/llsdutil.h b/indra/llcommon/llsdutil.h index eaf8825791..eddaa64bd2 100644 --- a/indra/llcommon/llsdutil.h +++ b/indra/llcommon/llsdutil.h @@ -31,6 +31,7 @@ #include "llsd.h" #include +#include #include // U32 @@ -601,6 +602,11 @@ auto apply_impl(CALLABLE&& func, const LLSD& array, std::index_sequence) return std::forward(func)(LLSDParam(array[I])...); } +/** + * apply(function, LLSD) goes beyond C++17 std::apply(). For this case + * @a function @emph cannot be variadic: the compiler must know at compile + * time how many arguments to pass. This isn't Python. + */ template auto apply(CALLABLE&& func, const LLSD& args) { -- cgit v1.2.3