first time without state - and I'm lost
Hi everyone,
I wanted to give a try to Clojure and functional programming in general but
I can't really stop thinking "object oriented" or "with state everywhere".
After 20+ years with objects + state I guess I'm lost without them :)
The first thing I want to try is to get some data from an API that needs
OAuth authentication. I would like to hide the fact that there's an OAuth
token to be sent. In pseudo-Java I would do something like:
class MyAuthHttpClient {
private token;
public MyAuthHttpClient(String usr, String psw) {...}
public ... getResponse(Url) {
// here check if token is available and if it is expiring;
// if expiring -> fetch a new token before call the http service
// caller doesn't even know there's a token involved in the process
}
}
What's the proper way to do that in Clojure?
I guess one way would be to have a function that returns a new token given
a (possibly old) token and user+psw
(defn gettkn [usr, psw, tkn] (return a new token if tkn is expiring or tkn if
not expiring))
(def wrap-gettkn (partial gettkn "myuser" "mypass"))
(defn geturl [url, tkn] client/get url {:oauth-token (wrap-gettkn tkn)})
I can "save" usr and psw, but I always have to "keep" the tkn around at
every level;
while I would like the token to be "hidden" to the "geturl" clients (just
like I did in the "private token" in the pseudo-Java).
What's the proper way of doing something like this in Clojure?
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Re: “compiling” stacktrace error
On Friday, February 12, 2016 at 9:51:50 AM UTC+1, Scaramaccai wrote: > > > > On Thursday, February 11, 2016 at 9:54:19 PM UTC+1, Sean Corfield wrote: >> >> Scaramaccai wrote on Thursday, February 11, 2016 at 8:32 AM: >> >I'm learning Clojure, and I find difficult to understand where a >> specific compiler error happens: >> >> The stacktraces can be pretty daunting at first, unfortunately. >> >> How are you compiling / running the code? That will have some bearing on >> how errors are reported. >> >> > Yes, the problem seems to be how I compiled the code. I was using > Vim+Fireplace, and doing a "cpr" (takes the content from the active buffer > and requires it inside the REPL) I had the error without a proper > stacktrace (see below). Running using "reipl run" gives the "proper" > stacktrace: > BTW using (.printStackTrace *e) >From inside the REPL gave me the full stack... so I can actually keep using Fireplace and get the full stack when needed. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: “compiling” stacktrace error
On Thursday, February 11, 2016 at 9:54:19 PM UTC+1, Sean Corfield wrote: > > Scaramaccai wrote on Thursday, February 11, 2016 at 8:32 AM: > >I'm learning Clojure, and I find difficult to understand where a specific > compiler error happens: > > The stacktraces can be pretty daunting at first, unfortunately. > > How are you compiling / running the code? That will have some bearing on > how errors are reported. > > Yes, the problem seems to be how I compiled the code. I was using Vim+Fireplace, and doing a "cpr" (takes the content from the active buffer and requires it inside the REPL) I had the error without a proper stacktrace (see below). Running using "reipl run" gives the "proper" stacktrace: [...] Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IPersistentCollection at clojure.core$conj__4345.invokeStatic(core.clj:82) at clojure.core$conj__4345.invoke(core.clj:82) at fwpd.core$fib_seq3.invokeStatic(core.clj:98) at fwpd.core$fib_seq3.invoke(core.clj:92) at fwpd.core$fib_seq3.invokeStatic(core.clj:94) at fwpd.core$fib_seq3.invoke(core.clj:92) at fwpd.core$eval70.invokeStatic(core.clj:105) at fwpd.core$eval70.invoke(core.clj:105) at clojure.lang.Compiler.eval(Compiler.java:6927) at clojure.lang.Compiler.load(Compiler.java:7379) *Thank you!!!* Fireplace+REPL stacktrace: || java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IPersistentCollection, compiling:(fwpd/core.clj:100:1) || clojure.lang.Compiler.load(Compiler.java:7391) || clojure.lang.RT.loadResourceScript(RT.java:372) || clojure.lang.RT.loadResourceScript(RT.java:363) || clojure.lang.RT.load(RT.java:453) || clojure.lang.RT.load(RT.java:419) zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5893| clojure.core$load$fn__5677.invoke zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5892| clojure.core$load.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5876| clojure.core$load.doInvoke || clojure.lang.RestFn.invoke(RestFn.java:408) zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5697| clojure.core$load_one.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5692| clojure.core$load_one.invoke zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5737| clojure.core$load_lib$fn__5626.invoke zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5736| clojure.core$load_lib.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5717| clojure.core$load_lib.doInvoke || clojure.lang.RestFn.applyTo(RestFn.java:142) zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|648| clojure.core$apply.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5774| clojure.core$load_libs.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5758| clojure.core$load_libs.doInvoke || clojure.lang.RestFn.applyTo(RestFn.java:137) zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|648| clojure.core$apply.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5796| clojure.core$require.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|5796| clojure.core$require.doInvoke || clojure.lang.RestFn.invoke(RestFn.java:421) || fwpd.core$eval3604.invokeStatic(form-init936506867427907734.clj:1) || fwpd.core$eval3604.invoke(form-init936506867427907734.clj:1) || clojure.lang.Compiler.eval(Compiler.java:6927) || clojure.lang.Compiler.eval(Compiler.java:6890) zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|3105| clojure.core$eval.invokeStatic zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\core.clj|3101| clojure.core$eval.invoke zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\main.clj|240| clojure.main$repl$read_eval_print__7408$fn__7411.invoke zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::clojure\main.clj|240| clojure.main$repl$read_eval_print__7408.invoke zipfile:C:\Users\105066315\.m2\repository\org\clojure\clojure\1.8.0\clojure-1.8.0.jar::c
“compiling” stacktrace error
I'm learning Clojure, and I find difficult to understand *where* a specific compiler error happens: java.lang.ClassCastException: java.lang.Long cannot be cast to clojure.lang.IPersistentCollection, compiling:(fwpd/core.clj:100:1) Line 100 is just: (fib-seq3 5) So it says nothing, because in fact the error is in the fib-seq3 function (parameters to a "conj" call are inverted, see below). Is this normal? No way to know where an error is??? Just for reference, here's the code (again, *I know where the error is*; I just don't understand how was I supposed to find it, given that the message doesn't tell me at which line it happens): (defn fib-seq3 ([to] (fib-seq3 [] 0 1 0 to)) ([coll a b k to] (if (= k to) coll (fib-seq3 (conj b coll) b (+ a b) (inc k) to))) (fib-seq3 5) Thank you! -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
