On Jul 8, 2014, at 7:08 PM, Cecil Westerhof <cldwester...@gmail.com> wrote:
> 2014-07-08 23:11 GMT+02:00 Bob Hutchison <hutch-li...@recursive.ca>: > > On Jul 8, 2014, at 9:40 AM, Cecil Westerhof <cldwester...@gmail.com> wrote: > > > In Clojure you can define a local constant with let, but I need a variable > > (I think). > > > > I want to do the following. I have a function that checks several things. > > Every time an error is found I want to set the variable errors to: > > (concat errors new-error) > > > > Is this possible? Or is there a better way to do this? > > Here's a different take on your question, and a few comments about how I'd > write that code. I don't think you need the atom -- kinda ugly and the > reduce/map/filter family of sequence functions will take you a long way. > > ; This is not a predicate, so don't use the -p suffix (and in Clojure it's a > ? normally) > > As I understood it (I am rewriting land of lisp to Clojure) that when a > function returns a true/false state, that you then use the -p suffix. When > returning () there are no errors. But I should use the ? then? You’re returning a list of errors. You can interpret that as a truthy/falsy kind of thing, in which case make sure you’re returning a nil for the no-error case. And use the ‘?’ in Clojure. > > > ; There's no reason not to pass those two objects into this function, so I do. > > Good idea. Makes it easy to test the function also. it does > > […] > > I hope you can make sense of that :-) > > Not immediately. I need to digest it. Have fun. > > By the way. The current function is only the start of the checks. After > the if I need to do several other checks also. So I think I do need the atom. > But maybe I am mistaken. ;-) I thought maybe your checks would be a little more than that. That’s why I left the ‘reduce’ version in there. Just make the function that is applied by reduce more powerful, perhaps pull it out into a separate function rather than an inline anonymous function. This will work as long as all tests are performed on one object at a time. No matter what, I’d recommend not going using an atom if you can help it. Cheers, Bob > > -- > Cecil Westerhof > > -- > 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. -- 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.
