On Tue, Oct 6, 2009 at 9:14 PM, Stephen C. Gilardi squee...@mac.com wrote:
`(do (set-validator! (defvar ~name ~init) #{~init}) (var ~name)))
Cute hack. Won't work if init is false or nil, though, unless the validator
does not trigger on the initial assignment of the value.
Hi,
On Oct 7, 7:53 am, John Harrop jharrop...@gmail.com wrote:
On Tue, Oct 6, 2009 at 9:14 PM, Stephen C. Gilardi squee...@mac.com wrote:
`(do (set-validator! (defvar ~name ~init) #{~init}) (var ~name)))
Cute hack. Won't work if init is false or nil, though, unless the validator
does
2009/10/7 Stephen C. Gilardi squee...@mac.com
On Oct 2, 2009, at 10:29 AM, Mark wrote:
Is there a way to make a declaration in Clojure that cannot be rebound
later? Ideally, I'd like something that fails if I try to do this:
(def myname mark)
; ...more code, elided...
(def myname Mark)
2009/10/7 Stephen C. Gilardi squee...@mac.com
On Oct 2, 2009, at 10:29 AM, Mark wrote:
Is there a way to make a declaration in Clojure that cannot be rebound
later? Ideally, I'd like something that fails if I try to do this:
(def myname mark)
; ...more code, elided...
(def myname Mark)
On Oct 7, 2009, at 5:19 AM, Meikel Brandmeyer wrote:
Or is setting the validator calling it on the already set value?
Yes, the validation mechanism calls the validator on the already set
value.
--Steve
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On Oct 7, 2009, at 12:47 AM, Mark Tomko wrote:
This is pretty much what I'd had in mind.
Thanks for the comments and suggestions all.
I don't see how the text of
the Exception is set by the macro, but it'd be really spectacular if
the message were more clear. Is that message coming from
from the API docs:
(defonce myname Walter)
; ...
(defonce myname Schnell)
= nil
myname
= Walter
hope this helps ;-)
On 2 Okt., 16:29, Mark mjt0...@gmail.com wrote:
Is there a way to make a declaration in Clojure that cannot be rebound
later? Ideally, I'd like something that fails if I try
+1
In my relatively novice opinion, unless there is a reason to make
functions and vars available to code executing in a *different*
namespace, there isn't a lot of reason to def anything at all.
On Oct 2, 11:48 am, Jonathan Smith jonathansmith...@gmail.com wrote:
I use a let at the top of the
On Oct 2, 2009, at 10:29 AM, Mark wrote:
Is there a way to make a declaration in Clojure that cannot be rebound
later? Ideally, I'd like something that fails if I try to do this:
(def myname mark)
; ...more code, elided...
(def myname Mark)
Along these lines, I was thinking of adding
On Oct 2, 11:52 am, Mark Tomko mjt0...@gmail.com wrote:
However, outside the scope of a function, it seems that it's possible
for bindings to be redefined later in a file without causing an
immediate error. This could easily lead to mistakes that would
manifest as silent and potentially
This is pretty much what I'd had in mind. I don't see how the text of
the Exception is set by the macro, but it'd be really spectacular if
the message were more clear. Is that message coming from the defvar
form?
On Oct 6, 6:14 pm, Stephen C. Gilardi squee...@mac.com wrote:
On Oct 2, 2009, at
Is there a way to make a declaration in Clojure that cannot be rebound
later? Ideally, I'd like something that fails if I try to do this:
(def myname mark)
; ...more code, elided...
(def myname Mark)
Perhaps this is obvious, but I see a lot of discussion of immutable
data structures, but I
I can think of 'defvar that comes close to what you're about : it does not
rebind the root value if it is different from nil
(though it doesn't warn you about the problem, it's more to prevent
reinitializing vars when their containing files are reloaded)
2009/10/2 Mark mjt0...@gmail.com
Is
Hi,
On Oct 2, 4:29 pm, Mark mjt0...@gmail.com wrote:
Is there a way to make a declaration in Clojure that cannot be rebound
later? Ideally, I'd like something that fails if I try to do this:
(def myname mark)
; ...more code, elided...
(def myname Mark)
Perhaps this is obvious, but I
When I write code in Java, I declare everything final that's possible
to be declared final, and I deliberately look for solutions that avoid
reassignment to variables, so all my variables are final).
I'm new to Clojure, so I might be wrong, but it seems that within a
function, mutable bindings
On Oct 2, 11:52 am, Mark Tomko mjt0...@gmail.com wrote:
However, outside the scope of a function, it seems that it's possible
for bindings to be redefined later in a file without causing an
immediate error. This could easily lead to mistakes that would
manifest as silent and potentially
From what I've seen, people never redef vars in source code. In general,
you shouldn't have to worry about users of your code redefing your vars as
it's against common convention, non-idiomatic.
The exception, as Stuart Sierra said, is when writing interactively from the
REPL, where you'd like
Also, I'm not sure if your understanding of binding is correct.
because within any lexical scope inside a function, I can
pretty much count on my bindings to never change.
binding is actually like a lexical re-def:
user= (def x 1)
#'user/x
user= (binding [x 2] (pr x) (binding [x 3] (pr x))
I use a let at the top of the file to denote things that I want to
have as captured and constant.
... you can do things like
(let [x 1]
(defn foo-that-uses-x [y]
(function-here x y)))
On Oct 2, 10:29 am, Mark mjt0...@gmail.com wrote:
Is there a way to make a declaration in Clojure that
That's what I meant when I mentioned the 'binding' form above. The
reason that's okay (to me) is that it explicitly calls out that
bindings may be about to change.
On Oct 2, 11:47 am, John Newman john...@gmail.com wrote:
Also, I'm not sure if your understanding of binding is correct.
because
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