Hlsl

#include <luisa/vstl/string_builder.h>

vstd::StringBuilder builder;
builder.clear();
size_t sz = builder.size();
vstd::string_view view = builder.view();
char* data = builder.data();

str.append("Hello");
str += "World"sv;
str.append(' ');
str << '\n';
str.append(other_builder);
str << "func" << '(' << ")";

vstd::to_string(42, str);        // int (faster than format)
vstd::to_string(3.14f, str);     // float
str << luisa::format("{}", 42);
str << luisa::format("{}, {}!", "Hello", "World");
str << luisa::format("{:016X}", hash);

using namespace std::string_view_literals;
str += "void"sv;  // no allocation

void GetFunctionDecl(Function func, vstd::StringBuilder &str) {
    vstd::StringBuilder data;
    if (func.return_type()) CodegenUtility::GetTypeName(*func.return_type(), data, Usage::READ);
    else data += "void"sv;
    data += " "sv;
    CodegenUtility::GetFunctionName(func, data);
    data += '(';
    for (auto &&arg : func.arguments()) {
        Usage usage = func.variable_usage(arg.uid());
        CodegenUtility::GetTypeName(*arg.type(), data, usage);
        data << ' ';
        vstd::StringBuilder varName;
        CodegenUtility::GetVariableName(func, arg, varName);
        data << varName << ',';
    }
    if (!func.arguments().empty()) data[data.size() - 1] = ')';
    else data += ')';
    str << '\n' << data;
}

str << "template<"sv;
for (uint64 i = 0; i < tempIdx; ++i) {
    str << "typename T"sv; vstd::to_string(static_cast<int64_t>(i), str); str << ',';
}
if (tempIdx > 0) *(str.end() - 1) = '>';

str << "func_name"sv << '(';
if (!args.empty()) {
    for (size_t i = 0; i < args.size() - 1; ++i) { args[i]->accept(vis); str << ','; }
    args.back()->accept(vis);
}
str << ')';

if (t->is_texture() || t->is_buffer()) { str << 'T'; vstd::to_string(tempIdx++, str); }
else if (t->is_vector()) { str << "float"sv; vstd::to_string(t->dimension(), str); }
else if (t->is_matrix()) { auto n = vstd::to_string(t->dimension()); str << "_float"sv << n << 'x' << n; }

struct CodeWrapper {
    vstd::StringBuilder *_result;
    CodeWrapper(vstd::StringBuilder *r, string_view open) : _result(r) { if (_result) *_result << open; }
    ~CodeWrapper() { if (_result) *_result << ')'; }
};
CodeWrapper wrapper{&str, "to_float4x4("};
// inner content generated; ')' appended automatically

str << '(';
for (auto &&item : items) str << item << ',';
if (!items.empty()) str[str.size() - 1] = ')';
else str << ')';

for (char c : str) {}
str.erase(str.begin() + 5);
vstd::hash<vstd::StringBuilder> hasher; size_t h = hasher(builder);
if (builder1 == builder2) {}
if (builder1 == "literal"sv) {}

#include <backends/common/hlsl/builtin/hlsl_builtin.hpp>
auto header = lc_hlsl::get_hlsl_builtin("hlsl_header");
std::string_view code(static_cast<const char*>(header.ptr), header.size);