That is a lot cleaner than what I trying to do! Thank you!

I think assertions can have a lot of value in production - I would use them wisely and keep them always on.

Thanks! I can truss's have! for those that should be kept in production.

The last line there will actually become

(str "Request Object: " req foo)

Ah, I get it now. Have been mocking some calls around. The use of the ->> macro isn't really required IMO as the result is indeed nil and won't affect the str call. Could this have been a simple do function?

If you just want to do both lines, maybe you want do instead ?

:body (do
        (pp/print req)
        (str "Request Object: " req))

Yeah, that's also what I'm thinking. Kind of reinforces my belief that there is a lot of bad content on medium :face_with_hand_over_mouth:

I have a DDG addon for Firefox that lets you blocks domains from search results. One of the domains I block is http://medium.com, found its mostly crap.

As @U050ECB92 mentioned, macroexpand is nice for getting an idea of what’s happening. Depending on your preference you might also want to look into using cond-> , though you’ll be adding some truthy indicator to every step that should always be running.

(let [new-payload (cond-> page-data
                    :always (select-keys [:title :type :body :metadata])
                    :always (assoc :version "v1")
                    (contains? (get-in page-data [:metadata :properties]) :editor)
                    (update-in [:metadata :properties :editor]
                               merge {:key "editor"
                                      :value "v1"}))]
  (println new-payload))

I switched to update-in for the example since your snippet was using assoc with a path which will actually turn into a key 😊

(assoc nil [:my :path] :value :another :value)
; => {[:my :path] :value, :another :value}

Awesome Thanks @UDB2Q0W13 It works for me.

No probs! Did you try macroexpanding yet? Illustrating what happens by switching out -> with as->:

(as-> page-data x
  (select-keys x [:title :type :body :metadata])
  (assoc x :version "v1")
  (if x
    (contains? (get-in page-data [:metadata :properties]) :editor)
    (assoc [:metadata :properties :editor] :key "editor" :value "v1")))

(-> 1
 dec
 (#(if (zero? %) "Zero!" "Not zero")))

(as-> 1 x
 (dec x)
 (#(if (zero? %) "Zero!" "Not zero") x))

Always Be Comparing and setting

Use fnil with update-in for missing initial values (0, [], etc)

Use for wrapped in a recursive function to process tree shaped data (fn f [xs] (for [x xs i (f x)] i))

ifn? is true for all invokable things (fns, multimethods, keywords, collections, vars, ...) but fn? only returns true for fns. Prefer ifn?

You can give otherwise anonymous functions a name to refer to itself by, which is useful for recursion, but the name will also show up in stacktraces so is useful when debugging (fn thisisthename [anarg] anarg)

str is the identity function on strings, and is type hinted to return a String. You can use str instead of adding a String type hint to remove reflection.

Use update-in instead of assoc-in, you can always turn update-in into assoc-in using constantly

identity is the identity transducer, pass it anywhere you would a transducer to get the bare step function behavior

Nice

clojure.set/index can be used to build more complex key/value lookup structures like a database index

Sometimes(usually for debugging) you just want to stick a function literal in the middle of a -> or ->>, this won't work like (-> ... #(f 1 % 2) ...) but will work like (-> ... (#(f 1 % 2)) ...)

Loop/recur cannot be used to loop across a try/catch, trampoline is useful for retry loops on exception

You can use (sort-by - ...) as a handy reverse sort in some cases, but not all, see https://clojure.org/guides/comparators for a complete write up on clojure (and java) sorting

reducing for side effects is very nice, but as much as possible return some value from reducing, not just nil. Even just a count of reductions can be useful when debugging, testing, and logging.

clojure.core/deref works on anything that implements clojure.lang.IDeref or java.util.concurent.Future, as a consequence of how that is implemented if you try to deref something that is not derefable, you get an error about casting to Future failing.

tree-seq is for harvesting trees. it enumerates all the parts of the tree and you can keep want you want.

Calling str on a lot of clojure objects gives you a nice readable thing, but not on all clojure objects. Use pr-str instead

proxy is really weird. In 10+ years I've never used update-proxy. And proxy-super is not thread safe(it mutates the proxy object).

A lot of metaprogramming kind of things don't even need macros, just intern

nice thread

How are you using hiccup? do you inline styles with it as well?

FYI: There are a couple of webapps that translate html-to-hiccup if you have some HTML and want to just paste it in and see how it would look as hiccup syntax. e.g. http://html2hiccup.buttercloud.com/

@U01EFUL1A8M I think I'm using in-line styles... I'm following an example from ClojureBridge London. Here's a snippet where I have an image in the navigation bar that I'd like to make bigger (not sure if there's padding that's making it smaller):

(defn navigation-top
  []
  ;; Navigation bar (responsive)
  [:nav {:class      "navbar is-fixed-top is-white has-shadow py-3"
         :role       "navigation"
         :aria-label "main navigation"}
   [:div {:class "container"}
    [:div {:class "navbar-brand"}
     [:a {:class "navbar-item"
          :href  "/"}
      [:img {:src "img/logo.png"}]]
     [:span {:class       "navbar-burger burger"
             :data-target "navbarClojureBridge"}
      ;; Empty spans needed for navbar burger
      [:span] [:span] [:span]]]
    [:div {:id    "navbarClojureBridge"
           :class "navbar-menu"}
     [:div {:class "navbar-end"}
      [:a {:class "navbar-item"
           :href  "/contact"
           :style {:font-weight "bold"}} "Contact"]]]]])

@U05476190 Thanks! That's a great resource. I think now I'll feel a lot more comfortable googling html questions nkowing that I can translate them into hiccup

I think with the navbar the problem is that there is padding around the image, but I don't know how to get rid of it. I'm using bulma, so would I have to go digging through the bulma file?

> not sure if there's padding that's making it smaller Forget about html vs hiccup for a minute; you really want to get more comfortable with Chrome and/or Firefox Developer Tools. That will help you answer those kinds of questions, quickly test alternatives, and find the source of what's causing the root issue (e.g. some bulma class, some padding, etc). IMO, that is time well spent and will save you a lot of grief in the long run. ;)

Thanks!! I appreciate you pointing me in a productive direction

Another question: For example, I want text within a div to be centered vertically. I did a google search and found

.center {
  margin: auto;
  width: 50%;
  border: 3px solid green;
  padding: 10px;
}

I'd prefer to stick to the hiccup files as much as I can instead of trying to change the css & html directly (Although I'd love to hear what best practices are?)

[:div {:style "margin: auto"} "Center Me"]

[:div {:class "center"} "Center Me"]

Cool thanks!!

If you are looking for example projects, my landing page is written with ClojureScript, reagent and http://Bulma.io (actually it's mostly bluma) https://github.com/practicalli/practicalli.github.io