RedBeard0531

# This was created by cxx_modules_builder. DO NOT EDIT.
MAKE_NINJA = /home/mstearn/opensource/cxx_modules_builder/modules_builder.py
CXX = /usr/sbin/clang++

# START HEADER
COMMONFLAGS = -stdlib=libc++ -pthread
DEBUGFLAGS = -ggdb3 -gsplit-dwarf
CXXFLAGS =  -fcolor-diagnostics -fPIC -Isrc -Ibuild/src  -Isrc/external/pegtl/include/tao/ -std=c++2a -DREALM_DEBUG=1 $COMMONFLAGS $DEBUGFLAGS
LIBS = -lcrypto -lc++experimental
LINKFLAGS = -fuse-ld=lld $COMMONFLAGS

RedBeard0531

Supplement to this video. Watch first 35 min (the language bits), then 1:14:30 - 1:18:15 (the new map features).

You can find a fairly comprehensive list of new features on cppreference or here if you really want to see it all.

Recap of features described in the video

RedBeard0531

#pragma once

#include <iterator>
#include <utility>
#include <coroutine>

// Only need one of these. Shouldn't depend on generator's T.
struct generator_sentinel {};

template <typename T>

RedBeard0531

// derived from http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Parallel_algorithm

function map() {
    emit(1, // Or put a GROUP BY key here
         {sum: this.value, // the field you want stats for
          min: this.value,
          max: this.value,
          count:1,
          diff: 0, // M2,n:  sum((val-mean)^2)
    });

RedBeard0531

-------------------------------- MODULE OT --------------------------------
EXTENDS Integers, TLC, FiniteSets, Sequences

CONSTANTS i_set, i_inc, i_nop \* Instruction model values
CONSTANT NULL

CONSTANT ImprovedAlgo

ASSUME ImprovedAlgo \in BOOLEAN

RedBeard0531

export module quux;
export struct quux{};

///////////

// bar.h
import quux

/////////

RedBeard0531

clang++ -std=c++2a -x c++-module iface.cpp --precompile -o iface.pcm -stdlib=libc++ 
clang++ -std=c++2a -x c++ consumer.cpp -c  -o consumer.o -fmodule-file=iface.pcm  -stdlib=libc++         

echo <<OUTPUT
In file included from consumer.cpp:2:
In file included from /usr/include/c++/v1/string:505:
In file included from /usr/include/c++/v1/string_view:176:
In file included from /usr/include/c++/v1/__string:57:
In file included from /usr/include/c++/v1/algorithm:643:
/usr/include/c++/v1/utility:574:1: error: redeclaration of deduction guide

RedBeard0531

// {{{
// vim: set foldmethod=marker: 
// g++ -O3 -pthread sc.cpp && ./a.out
#include <cstdio>
#include <thread>
#include <atomic>
using namespace std;

constexpr auto load_order = memory_order_acquire;
constexpr auto store_order = memory_order_release;

RedBeard0531

(depth 1 are direct includes from the cpp)

A single file from our codebase:
28 headers at depth 1
35 headers at depth 2
50 headers at depth 3
74 headers at depth 4
82 headers at depth 5
89 headers at depth 6
127 headers at depth 7

RedBeard0531

// A possible implementation of symmetic coroutines on top of the asymmetric coroutines ts.
// At the bottom of this file, I've rewritten the symmetric examples from Boot.Coroutine
// using this mechanism. You can see the originals at 
// https://www.boost.org/doc/libs/1_69_0/libs/coroutine/doc/html/coroutine/coroutine/symmetric.html

#include <experimental/coroutine>
#include <cassert>
#include <list>
#include <optional>
#include <vector>