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1 point by hasenj 4864 days ago | link | parent

Well then, back to my original question: how do you compose elements together?


3 points by thaddeus 4862 days ago | link

So I gave it another whirl and here's my attempt to capture the essence of you're problem:

For example you would like to do this:

  [1] arc> (spanclass "links" 
             (string "use this link:" 
               (tag (a href "http://mydomain.com/the-place-to-go") "here"))
And have it return this:

  <span class="links">use this link:<a href="http://mydomain.com/the-place-to-go">here</a></span>
and your first attempt might be something like this:

  [2] arc> (spanclass "links" 
             (pr:string "use this link:" 
               (tag (a href "http://mydomain.com/the-place-to-go")(pr "here")))
only you find it returns the wrong results:

  <span class="links"><a href="http://mydomain.com/the-place-to-go">here</a>use this link:</span>
so now you're probably thinking by having functions return strings like this:

  [3] arc> (tag (a href "http://mydomain.com/the-place-to-go") "here")
  "<a href=\"http://mydomain.com/the-place-to-go\">here</a>"
then the original function [1] would have worked.

Instead, with arc, you need to approach your code differently. You need to think about the timing of when things are happening rather than having available 'string-things' that you can compose by nesting your functions.

So with arc [1] needs to become [4]:

  [4] arc> (spanclass "links" 
            (pr "use this link:")
            (tag (a href "http://mydomain.com/the-place-to-go")(pr "here")))

  <span class="links">use this link:<a href="http://mydomain.com/the-place-to-go">here</a></span>
Am I capturing it correctly? Does this answer your question on how I compose my functions?

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1 point by thaddeus 4864 days ago | link

I've re-looked into your original questions, in an attempt to provide a meaningful response, but I find the scenario's are not concrete enough.

For example I find the re-arrange function a little vague.

i.e. could you not:

  (def something (a b c)
      (output b c a))
Could you provide an real-case like example where you feel you can show a clear difference? For, I found, even your row example can easily work with stdout inside a function rather than using pg's macro. ie. Not liking how some of the existing functions/macros work doesn't mean string weaving is the answer.

And row is a pretty crappy example, even when I built my Clojure library, I ditched pg's implementation and went with a more useful implementation, yet it still uses stdout. You have to remember that pg only built those macro's to support his specific cases in his HN app.

Also, for > Too many tricks. Too clever.

Well it's a library, it's not expected you're crafting macros for your regular coding. I mean there's only so many HMTL cases you need to handle right? So if the library is complete, providing (macro's or not) succinct code and faster results, then it's probably good to have - tricks inside or not.

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