deque-blog

class SuggestPopularFriendPost {
    private final IAccessProfileInfo profileInfo;
    
    public SuggestPopularFriendPost(IAccessProfileInfo profileInfo) {
        this.profileInfo = profileInfo;
    }

    public Iterable<PostSummary> suggestedPostsFor(ProfileId profileId) {
        Iterable<ProfileId> friendIds = friendsOf(profileId);
        Set<Topic> topics = favoriteTopicsOf(profileId);

deque-blog

public Iterable<PostSummary> suggestedPostsFor(ProfileId profileId) {
    Iterable<ProfileId> friendIds = friendsOf(profileId);  // Get the friends of the current user
    // ...
}

deque-blog

public Iterable<PostSummary> suggestedPostsFor(ProfileId profileId) {
    Iterable<ProfileId> friendIds = friendsOf(profileId);  // Get the friends of the current user
    Set<Topic> topics = favoriteTopicsOf(profileId);       // Get the favorite topics of the current user
    Stream<PostSummary> friendsPosts = stream(friendIds)   // For each friend
            .flatMap(friendId -> lastPostsOf(friendId))    // * Get their last posts
            .filter(post -> post.isAbout(topics));         // * Keep those whose topic is relevant
    return mostLiked(3, friendsPosts);                     // Rank them by like count
}

private List<PostSummary> mostLiked(int count, Stream<PostSummary> posts) {

deque-blog

suggestedPostsFor userId = do
    friendIds <- friendsOf userId                     -- Get the friends of the current user
    topics <- favoriteTopicsOf userId                 -- Get the favorite topics of the current user
    friendsPosts <- forM friendIds $ \friendId -> do  -- For each friend
        posts <- lastPostsOf friendId                 -- * Get their last posts
        return (filter (isAbout topics) posts)        -- * Keep those whose topic is relevant
    return (mostLiked 3 friendsPosts)                 -- Rank them to keep only the bests

deque-blog

void f (Context const& context, ...);

void caller_from_rest(Context const& context)
{
  WithContext restContext("REST", "/api/v1.0/f");
  f(context, ...);
  // ... "REST" automatically removed at the end
}

deque-blog

void f (Context const& context, ...) {
  logger.info(context, "Doing stuff in function f");
}

void caller_from_rest(Context const& context) {
  context.put("REST", "/api/v1.0/f");
  // ...
  f(context, ...);
  // ...
  context.remove("REST");

deque-blog

void f(Context const& context) {
   // ...
   logger.info(context, "log message");
   // ...
}

deque-blog

class Context {
public:
   void put(key const&, json const&);
   void remove(key const&);
   std::map<key, json> getContext();
   //...
};

deque-blog

{-# LANGUAGE FlexibleInstances #-}
module LogContext (testLogContext) where

import Control.Concurrent
-- import Control.Concurrent.Async


--------------------------------------------------------------------------------
-- Abstract logger language
--------------------------------------------------------------------------------

deque-blog

;; Calling make-payment using named arguments
(make-payment
    {:money "10 EUR"
     :from "Alice"
     :to "Bob"})

;; Versus calling make-payment with positional arguments
(make-payment "10 EUR" "Alice" "Bob")