closure-library VS C++ Format

> "I recently learned that some Node.js engineers prefer stream classes when building strings, for performance reasons." Pretty much tells you everything you need to know about node js, I guess.

Google Closure Library includes a StringBuffer class. [1]

I recall it having explanatory notes, but I don't see them in the code now. JavaScript engines can optimize a string concatenating to in-place edit, if there is only one reference to the first string. The StringBuffer class keeps the reference count at one, guaranteeing this optimization is available, even if the StringBuffer itself is ever shared.

[1] https://github.com/google/closure-library/blob/master/closur...

This made me wonder what the oldest go-link (from inside Google) discoverable on the public internet is. So far I've found one going back to 2013 (but there should definitely be some from the mid 2000s): https://github.com/google/closure-library/blame/11ed104958a2...

(Fun fact: go-links are so critical to Google ops, that they're expected to be accessible in a "everything is down" scenario.)

For data type I always use DECIMAL(#, 6). So 6 decimal places. This accommodates all generally agreed upon rounding standards for calculating interest, taxes, discounts, etc. So for me, something like $12.75 USD will look like 12.750000 in the database. I store the 3-letter currency code in a separate column. I know what the base value for each currency is on the code side in our framework, which has a currency library that reads a dataset that has every currency stored like this (the 'rules' key is a bitmask per Google's i18n currency.js):

Continuation passing monads form the basis of a perfectly valid and usable software architecture and programming pattern.

In the case of ostream and operator<<, this pattern reduces the number of intermediate objects that would otherwise be constructed.

If you object to iostream on religious or stylistic grounds, there's always fmt which is more like Go or Python string interpolation.[0]

0. https://fmt.dev

GitHub repo: fmtlib/fmt

cmake_minimum_required(VERSION 3.5) project(knn_cpp CXX) # Set up C++ version and properties include(CheckIncludeFileCXX) check_include_file_cxx(any HAS_ANY) check_include_file_cxx(string_view HAS_STRING_VIEW) check_include_file_cxx(coroutine HAS_COROUTINE) set(CMAKE_CXX_STANDARD 20) set(CMAKE_BUILD_TYPE Debug) set(CMAKE_CXX_STANDARD_REQUIRED ON) set(CMAKE_CXX_EXTENSIONS OFF) # Copy data file to build directory file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/iris.data DESTINATION ${CMAKE_CURRENT_BINARY_DIR}) # Download library usinng FetchContent include(FetchContent) FetchContent_Declare(matplotplusplus GIT_REPOSITORY https://github.com/alandefreitas/matplotplusplus GIT_TAG origin/master) FetchContent_GetProperties(matplotplusplus) if(NOT matplotplusplus_POPULATED) FetchContent_Populate(matplotplusplus) add_subdirectory(${matplotplusplus_SOURCE_DIR} ${matplotplusplus_BINARY_DIR} EXCLUDE_FROM_ALL) endif() FetchContent_Declare( fmt GIT_REPOSITORY https://github.com/fmtlib/fmt.git GIT_TAG 7.1.3 # Adjust the version as needed ) FetchContent_MakeAvailable(fmt) # Add executable and link project libraries and folders add_executable(${PROJECT_NAME} main.cc) target_link_libraries(${PROJECT_NAME} PUBLIC matplot fmt::fmt) aux_source_directory(lib LIB_SRC) target_include_directories(${PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}) target_sources(${PROJECT_NAME} PRIVATE ${LIB_SRC}) add_subdirectory(tests)

Good catch, thanks! Fixed now. This explains why the difference was kinda low compared to another benchmark: https://github.com/fmtlib/fmt?tab=readme-ov-file#compile-tim....

> This is from C++23, right?

std::println is, yes.

> I wonder how available this is within compilers

https://en.cppreference.com/w/cpp/compiler_support says clang, gcc, and msvc all support it, though I don't know how recent those versions are off the top of my head.

In my understanding, with this specific feature, if you want a polyfill for older compilers, or to use some more cutting-edge features that haven't been standardized yet, https://github.com/fmtlib/fmt is available to you.

{fmt} has internal buffering but it's not yet exposed to users. There is a feature request for it: https://github.com/fmtlib/fmt/issues/2354. FILE buffering is not too bad but it can be easily optimized: https://www.zverovich.net/2020/08/04/optimal-file-buffer-siz....

Automatic use of operator<< when that exists was present in fmt until version 9.0.0. In version 9 you could use FMT_DEPRECATED_OSTREAM to opt in the old behaviour, but this too was removed in version 10.0.0. Now there is no way to automatically use operator<<.

You can install it https://github.com/fmtlib/fmt

Additionally, if you like low level stuff, check out libfmt (https://github.com/fmtlib/fmt) - not a big project, not difficult to understand. Or something like simdjson (https://github.com/simdjson/simdjson).