Write can produce pretty output directly to a string and without the
trailing newline, making this a little shorter:
(defn- apply-macro-expander [expander string]
(binding [*print-suppress-namespaces* true]
(with-pprint-dispatch *code-dispatch*
(write (expander (read-from-string string)) :pretty true :stream
nil))))
Completely untested! :-)
Tom
On Mar 12, 11:07 am, David Nolen <dnolen.li...@gmail.com> wrote:
> I suppose the following is more idiomatic:
>
> (defn- apply-macro-expander [expander string]
> (let [astr (with-out-str
> (binding [*print-suppress-namespaces* true]
> (with-pprint-dispatch *code-dispatch*
> (pprint (expander (read-from-string string))))))]
> (subs astr 0 (dec (count astr)))))
>
> > On Thu, Mar 12, 2009 at 12:53 PM, Tom Faulhaber
> > <tomfaulha...@gmail.com>wrote:
>
> >> Expanding on David's earlier example of pretty printing, we can set
> >> the dispatch to *code-dispatch* and bind *print-suppress-namespaces*
> >> to true and get the following (apologies for google messing up my
> >> formatting):
>
> >> (do
> >> (defmacro dft2 [tree]
> >> (seq (concat (list '=dft2) (list '*cont*) (list tree))))
> >> (defn =dft2 [*cont* tree]
> >> (reset! *saved* nil)
> >> (let [*cont* (fn
> >> [node]
> >> (cond
> >> (= node 'done) (*cont* nil)
> >> :else (do (print node) (restart))))]
> >> (=dft-node *cont* tree))))
>
> >> Which is not always what you want, since it loses the namespace info
> >> that backquote adds, but for me it's usually what I want because it
> >> looks like the code I would have written.
>
> >> A couple of notes for the detail-oriented: You can see the special
> >> code formats for defmacro, defn, binding vectors, and cond in
> >> operation here. You can also see that fn needs special treatment and
> >> doesn't have it yet. (But it will, real soon now.)
>
> >> On Mar 12, 9:28 am, Tom Faulhaber <tomfaulha...@gmail.com> wrote:
> >> > Rich,
>
> >> > I would be happy to make it a contribution (it's the least I can do!).
> >> > I've had a CA sitting on my desk unread and unsigned for about 3
> >> > weeks. It is now read, signed, and in an envelope. I'll send it off
> >> > this morning.
>
> >> > Everyone,
>
> >> > Thanks for the kind words. I'm glad you like it.
>
> >> > David's use case in slime/swank was one of the motivators for me
> >> > writing this. Thanks for showing us how to do the integration, David!
> >> > I hope we see a lot of other use cases like that.
>
> >> > Upcoming is the ability to create custom dispatch tables which will
> >> > open the door to an even broader set of use cases.
>
> >> > On Mar 12, 1:56 am, Rich Hickey <richhic...@gmail.com> wrote:
>
> >> > > On Mar 12, 2009, at 3:05 AM, Tom Faulhaber wrote:
>
> >> > > > I have now "released" the first version of my pretty printer as part
> >> > > > of my cl-format library. It is released under the EPL.
>
> >> > > > The pretty printer has two functions that you probably care about:
>
> >> > > > (pprint obj) will pretty print the given object, and
> >> > > > (pp) at the REPL will pretty print the last result output, i.e. the
> >> > > > value in *1.
>
> >> > > > The pretty printer currently supports two modes: simple and code.
> >> > > > Simple mode prints structure in a standard way that's good for data.
> >> > > > Code mode understands lots of Clojure forms (defn, binding vectors,
> >> > > > condp, etc.) and attempts to print them in an idiomatic way.
>
> >> > > > Cl-format is on github athttp://github.com/tomfaulhaber/cl-format.
> >> > > > There is a Readme there with instructions, examples, limitations and
> >> > > > futures. I won't even try to put examples here, because google
> >> groups
> >> > > > wreaks havoc on formatting.
>
> >> > > > The simplest way to get some pretty printing happiness:
> >> > > > 1) Download the jar:
> >>http://github.com/tomfaulhaber/cl-format/raw/master/release/cl-format...
> >> > > > 2) Put it in your classpath.
> >> > > > 3) Fire up your REPL
> >> > > > 4) (use 'com.infolace.format)
> >> > > > 5) Use pprint and pp as described above.
>
> >> > > > This is definitely a first release and there are sure to be bugs.
> >> And
> >> > > > I know there are things missing. So let me know if you're having
> >> > > > problems and I'll try to get things fixed up ASAP.
>
> >> > > > Enjoy!
>
> >> > > > Tom
>
> >> > > This looks very useful Tom. Would you consider contributing it to
> >> > > Clojure?
>
> >> > > Rich
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