@eslachance: more at https://clojure.org/guides/threading_macros

I'm going to go ahead and make a folder in my bookmark bar 😄

How can I start a clojure atom off with a system property

How can I make the if then it a let work. I have now this :

(let [prevnext (if (< page 6) (- 11 page) else 6)
      num-pages 466
      page 466
      lower (max 1 (- page prevnext))
      upper (inc (min num-pages (+ page prevnext)))]
  (range lower upper))  

and I see a message that if has to many arguments

the syntax is (if <condition> <true-expr> <false-expr>)

so (if (< page 6) (- 11 page) 6) is probably what you want

that's assuming page is defined earlier somewhere else in the code. otherwise you will get an error since page in the snippet above is defined after prevnext. the order is important with the let bindings

Thanks, I saw that error and solved it

so everything seems to work well

I have this function :

(ns paintings2.pagination)

(def pagination-numbers
  []
 (let [page (data.current-page)
       prevnext (if (< page 6) (- 11 page) (if (> page 460 ) (- 11 (- 467 page)) 5))
       num-pages 475
       lower (max 1 (- page prevnext))
       upper (inc (min num-pages (+ page prevnext)))]
  (range lower upper)))

now I use it like this :

{% for number in (paintings2.pagination/pagination-numbers()) %}

but now I see no output . it looks like the function returns nothing

Any tips how to solve this ?

the last line is in a Selmer template

can you call functions like that in selmer?

https://groups.google.com/forum/#!topic/luminusweb/QWzl1fibh9Y

@roelof You need to call the funtction in the clojure code that renders the selmer template. Check out the link I posted.

(render "{% for number in pagination-numbers %}" {:pagination-numbers (paintings2.pagination/pagination-numbers)})

@madstap thanks, I have some rwriting to do then

@madstap : one question. How can I make it work that in the for number loop I made a <li>

I think I can place the code you posted into the template ?

@roelof Not really sure what you're asking... You want something like this <ul>{% for number in pagination-numbers %}<li>{{number}}</li>{% endfor %}</ul>, right?

no, I want {% for .... } <li> ,,,, </li> <% end for %}

@madstap

Can I do something like this :

(render "{% for number in pagination-numbers %} <li> ....  </li>" {:pagination-numbers (paintings2.pagination/pagination-numbers)}) 

You can, but you need an {% endfor %} at the end of the string too

oke, both thanks, I will try that

nope, when I place this :

 (render "{% for number in pagination-numbers %} <li><a href="#"></a> number </li> {% endfor %}" {:pagination-numbers (paintings2.pagination/pagination-numbers)}) 

I see now this in my html :  (render "" {:pagination-numbers (paintings2.pagination/pagination-numbers)})

or can I not place this in my base.html file

You need to put it in the .clj file

bummer, I think I need to rethink the way I achieve my goal.

I want to display number which stands for pagenumbers. These are generated by the pagination-numbers function

in my base.html file I have a footer part where I want to display those numbers

How does the code where you render base.html look?

Should be something like:

I have this home.html page :

{% extends "base.html" %}

{% block content %}

 {% for painting in data.paintings %}

 <div class="post-masonry col-md-4 col-sm-6">
    <div class="post-thumb">
        <img src= {{ painting.tiles}} alt="">
        <div class="title-over">
            <h4><a href="#"> {{painting.title}} </a></h4>
        </div>
        <div class="post-hover text-center">
            <div class="inside">
                <i class="fa fa-plus"></i>
                <span class="date">25 Jan 2084</span>
                <h4><a href="#">Title one goes here</a></h4>
                <p>Cum sociis natoque penatibus et magnis dis parturient</p>
            </div>
        </div>
    </div>
</div> <!-- /.post-masonry -->

 {% endfor %}

{% endblock %}

which responds to this route :

(layout/render
      "home.html" {:data {:paintings (-> (client/get url options)
                                      (api/get-objectNumbers)
                                      (api/fetch-paintings-and-images-front-page))
                          :current-page page-num}})))

Right, this is where you need to add the :pagination-numbers key

oke, so I f I add a pagination-numbers key in home.html , base.html can use it

oke, I will try it that way after dinner

I thought base.html would not find it

and in base,html I can do

{%  for number in data.pagination-number  %}  

yes

thanks, I will try it after dinner

If :pagination-numbers is a sequence of numbers

yep, it returns a range of numbers

one problem.

I have this part :

"home.html" {:data {:paintings (-> (client/get url options)
                                      (api/get-objectNumbers)
                                      (api/fetch-paintings-and-images-front-page))
                       :current-page page-num
                       :pagination-numbers (pagination/pagination-numbers)}}))

which calls this function :

(ns paintings2.pagination)

(def pagination-numbers
  []
 (let [page (data.current-page)
       prevnext (if (< page 6) (- 11 page) (if (> page 460 ) (- 11 (- 467 page)) 5))
       num-pages 475
       lower (max 1 (- page prevnext))
       upper (inc (min num-pages (+ page prevnext)))]
  (range lower upper)))

but now I see this error message :

Too many arguments to def, compiling:(paintings2/pagination.clj:3:1) 

you need defn instead of def

thanks

I have this in my require :

[paintings2.pagination :as pagination]  

and see this error :

namespace 'paintings2.pagination'  

what does your full ns statement look like?

(ns paintings2.routes.home
  (:require [paintings2.layout :as layout]
            [compojure.core :refer [defroutes GET]]
            [ring.util.http-response :as response]
            [ :as io]
            [compojure.route :refer [resources]]
            [environ.core :refer [env]]
            [paintings2.api-get :as api]
            [paintings2.pagination :as pagination]
            [clj-http.client :as client]
            [clojure.spec :as s]))

and of the pagination :

(ns paintings2.pagination) 

ok, and what's the full error you're getting?

java.lang.Exception: namespace 'paintings2.pagination' not found, compiling:(paintings2/routes/home.clj:1:1) 

java.lang.Exception: namespace 'paintings2.pagination' not found, compiling:(paintings2/routes/home.clj:1:1)
        at clojure.core$throw_if.invokeStatic(core.clj:5771)
        at clojure.core$load_lib.invokeStatic(core.clj:5857)
        at clojure.core$load_lib.doInvoke(core.clj:5832)
        at clojure.lang.RestFn.applyTo(RestFn.java:142)
        at clojure.core$apply.invokeStatic(core.clj:659)

        at clojure.core$load_libs.invokeStatic(core.clj:5889)
        at clojure.core$load_libs.doInvoke(core.clj:5873)
        at clojure.lang.RestFn.applyTo(RestFn.java:137)
        at clojure.core$apply.invokeStatic(core.clj:659)
        at clojure.core$require.invokeStatic(core.clj:5911)
        at clojure.core$require.doInvoke(core.clj:5911)
        at clojure.lang.RestFn.invoke(RestFn.java:805)
        at paintings2.routes.home$eval17751$loading__7732__auto____17752.invoke(home.clj:1)
        at paintings2.routes.home$eval17751.invokeStatic(home.clj:1)
        at paintings2.routes.home$eval17751.invoke(home.clj:1)
        at clojure.lang.Compiler.eval(Compiler.java:6978)
        at clojure.lang.Compiler.eval(Compiler.java:6967)
        at clojure.lang.Compiler.load(Compiler.java:7430)

my guess is that paintings2/pagination.clj has an error somewhere

the expression (data.current-page) won't compile

oke, that comes from here :

(defn home-page [page]
  (let [page-num (s/conform ::page page)
        url ""
        options {:as :json :query-params {:key (env :key) :format "json" :type "schilderij" :toppieces "True" :p page-num :ps 10}}]
    (if (s/invalid? page-num) 1 page-num)
    (layout/render)
   "home.html" {:data {:paintings (-> (client/get url options)
                                      (api/get-objectNumbers)
                                      (api/fetch-paintings-and-images-front-page))
                       :current-page page-num
                       :pagination-numbers (pagination/pagination-numbers)}}))

pass in page-num as an argument instead, e.g. (pagination/pagination-numbers page-num)

data.current-page is referring to a namespace that doesn't exist in your project

furthermore, even if it were being used as a namespace, it's not a valid var because it's missing the symbol, i.e. data.current-page/my-var

if I understand you right, delete the current-page part and make it a parameter of the pagination-numbers function ?

you can delete :current-page page-num if it's not being used elsewhere

that's correct

in clojure when you have a function that needs data from somewhere else, it's usually best to just pass in the data as an argument

#rads. I have now this :

(defn home-page [page]
  (let [page-num (s/conform ::page page)
        url ""
        options {:as :json :query-params {:key (env :key) :format "json" :type "schilderij" :toppieces "True" :p page-num :ps 10}}]
    (if (s/invalid? page-num) 1 page-num)
    (layout/render)
   "home.html" {:data {:paintings (-> (client/get url options)
                                      (api/get-objectNumbers)
                                      (api/fetch-paintings-and-images-front-page))
                       :pagination-numbers (pagination/pagination-numbers page-num)}}))

(ns paintings2.pagination)

(defn pagination-numbers
  [page]
 (let [prevnext (if (< page 6) (- 11 page) (if (> page 460 ) (- 11 (- 467 page)) 5))
       num-pages 475
       lower (max 1 (- page prevnext))
       upper (inc (min num-pages (+ page prevnext)))]
  (range lower upper)))

but still the same error

it looks like to me there is something wrong in the require part

if you can run pagination-numbers from a REPL then you know the problem is in home.clj

the paintings2.pagination code works for me so it's probably in home.clj

the ns statement you pasted earlier looks fine to me

can you do (require 'paintings2.pagination) in a REPL?

lein is giving me a very weird error when i try to do anything:

Could not find artifact base:lein-template:jar:0.1.0-SNAPSHOT in clojars ()
This could be due to a typo in :dependencies or network issues.
If you are behind a proxy, try setting the 'http_proxy' environment variable.

i just reinstalled lein just to be on the safe side

upon further investigation, i can’t even seem to ping

@rads When I do it on a repl I get as output nil so I seems to work well

when I do

[paintings2.pagination :as pag] 

and if you change it back it gives you the error again?

very wierd, everything still works

but I see another errormessage

I have this :

(defn pagination-numbers
  [page]
 (let [prevnext (if (< page 6) (- 11 page) (if (> page 460 ) (- 11 (- 467 page)) 5))
       num-pages 475
       lower (max 1 (- page prevnext))
       upper (inc (min num-pages (+ page prevnext)))]
  (range lower upper)))

and on the prevnext line I see this error message :

clojure.lang.Keyword cannot be cast to java.lang.Number  

Here I test if the page is a valid number :

[page-num (s/conform ::page page) 

here it's a 1 or the orginal number :

(if (s/invalid? page-num) 1 page-num) 

so why is page-num suddenly a keyword ???

anyone a idea ?

When I do the pagination-numbers in repl then there is no problem ,

(pagination-numbers 5)  

@roelof putting in (println page) above your let might give you a clue

You can also put a binding to _ in your let and print out page-num

e.g.

(let [page-num (s/conform ::page page)
      _ (println page-num)
      other (bindings)]
  …)

@dominicm I have a clue. When I do that in the pagination function page seems to have this as content : :clojure.spec/invalid

what is wierd because this line

(if (s/invalid? page-num) 1 page-num) 

are you sure about that? 🙂

yep, I have checked that before : this line is checking if page is a valid number :

page-num (s/conform ::page page) 

and then here I check if pagenum is a number or invalid :

(if (s/invalid? page-num) 1 page-num) 

if it's invalid I 'change' page-num to 1

I have checked that before on repl

@roelof you're not changing it (in your example at least)

wierd, on test on repl which I did earlier It seems to work

What I tried to do is when a user uses localhost:3000 the request to the external api is containing the page-number 1

and that looks to happen

I do not get a error message that page-num is not a number

I have made this spec test to take care of it :

(defn ->long [s] (try (Long/parseLong s) (catch Exception _ ::s/invalid)))

(s/def ::page (s/and (s/conformer ->long) (s/int-in 1 471)))

(s/def ::optional-page (s/nilable ::page))

how can you make sure the if you pasted above is doing what you expect?

you are right. it's not going to work. I change the test to optional-page because page can be nill or a number and now I see a nullpointer exception

is there a better way to take care that page-num is always 1 or another number even if a user is using a non-valid-number or character

@roelof It could work without much altering. You just need to use your if in the let, e.g.

[page-num (s/conform page)
 safe-page-num (if (s/invalid? page-num) 0 page-num)
 …]

thanks that seems to be working

Now I have this part :

<div class="social-icons">
                            <ul>

                              {% for number in data.pagination-numbers %}

                                <li> number </li>

                              { % endfor %}


                            </ul>
                        </div>

and I see this error :

The template contains orphan tags.. 

data.pagination is coming from the home-route

when I deleting parts. It looks like the for part is not good

is there a way I can send data to the base,html without a route ?

{ % endfor %} should be {% endfor %}

yep

I have now to make the urls : Is there some tag for the base or can I do

<a href = /page={{number}}  

I want to make a url to the page that has that page-number

I could do < a href = localhost/?page = {{ number}} but then I hardcode the url

and I have to change it when the url is chancing

<a href=”?page={{number}}”>text</a> should work

That will just add ?page=N to the current URL.

@seancorfield not additive though. Worth noting, probably not relevant here though

@seancorfield thanks, I will implement that

I almost have the pagination problem solved

and yesterday I changed the layout one more time