Re: options for a function

2012-02-23 Thread Michael 

Jonas,

Thanks for pushing this out so quickly. We're using it now and it
works fine.

On Feb 23, 12:32 am, Jonas jonas.enl...@gmail.com wrote:

 * Quote only when necessary (this is the default)

This default is very handy.

Michael

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Re: options for a function

2012-02-22 Thread Mark Rathwell 
I don't know that there is necessarily a recommended way to offer
options.  Sometimes people want keyword options, sometime the want to
take options as a map, sometimes they need to do it one way or another
for various reasons, sometime they do it one way and later learn of a
better way.

To take options in the way you have specified, you can use
destructuring to simplify:

(defn write-csv [writer data  {:as opts}] ...)
  - or -
(defn write-csv [writer data  {:keys [separator quote ...]}] ...)
  - or -
(defn write-csv [writer data  {:keys [separator quote ...] :as opts}] ...)


On Wed, Feb 22, 2012 at 3:47 PM, Michael michael-a...@db.com wrote:
 clojure.data.csv has options for the following:

 (defn write-csv
  Writes data to writer in CSV-format.

   Valid options are
     :separator (Default \\,)
     :quote (Default \\\)
     :guote? (A predicate function which determines if a string should
 be quoted. Defaults to quoting only when necessary.)
     :newline (:lf (default) or :cr+lf)
  [writer data  options]
  (let [opts (into {} options)
        separator (or (:separator opts) \,)
        quote (or (:quote opts) \)
        quote? (or (:quote? opts) #(some #{separator quote \return
 \newline} %))
        newline (or (:newline opts) :lf)]
 snip

 Since (into {} options) is used to get the options into a map, it
 seems that you need to specify options in this (write-csv writer data
 [:separator \;] [:newline :lf+cr]).

 Is this the recommended way to offer options? I was expecting (write-
 csv writer data :separator \; :newline :lf+cr).


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Re: options for a function

2012-02-22 Thread Sean Corfield 
This seems like a bug in clojure.data.csv and someone should create a
JIRA ticket for it, perhaps with a patch?

http://dev.clojure.org/jira/browse/DCSV

This once again makes me question why this CSV library ended up in
contrib (without any discussion) rather than the more actively
maintained and widely used clojure-csv library by David Santiago -
https://github.com/davidsantiago/clojure-csv

On Wed, Feb 22, 2012 at 1:17 PM, Mark Rathwell mark.rathw...@gmail.com wrote:
 I don't know that there is necessarily a recommended way to offer
 options.  Sometimes people want keyword options, sometime the want to
 take options as a map, sometimes they need to do it one way or another
 for various reasons, sometime they do it one way and later learn of a
 better way.

 To take options in the way you have specified, you can use
 destructuring to simplify:

 (defn write-csv [writer data  {:as opts}] ...)
  - or -
 (defn write-csv [writer data  {:keys [separator quote ...]}] ...)
  - or -
 (defn write-csv [writer data  {:keys [separator quote ...] :as opts}] ...)


 On Wed, Feb 22, 2012 at 3:47 PM, Michael michael-a...@db.com wrote:
 clojure.data.csv has options for the following:

 (defn write-csv
  Writes data to writer in CSV-format.

   Valid options are
     :separator (Default \\,)
     :quote (Default \\\)
     :guote? (A predicate function which determines if a string should
 be quoted. Defaults to quoting only when necessary.)
     :newline (:lf (default) or :cr+lf)
  [writer data  options]
  (let [opts (into {} options)
        separator (or (:separator opts) \,)
        quote (or (:quote opts) \)
        quote? (or (:quote? opts) #(some #{separator quote \return
 \newline} %))
        newline (or (:newline opts) :lf)]
 snip

 Since (into {} options) is used to get the options into a map, it
 seems that you need to specify options in this (write-csv writer data
 [:separator \;] [:newline :lf+cr]).

 Is this the recommended way to offer options? I was expecting (write-
 csv writer data :separator \; :newline :lf+cr).

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Re: options for a function

2012-02-22 Thread Jonas 
I'll fix this today. 

Thanks,
Jonas

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Re: options for a function

2012-02-22 Thread Jonas 
I just pushed the fix to github and released version 0.1.2. Sorry for the 
inconvenience.

I'm not really happy with the write part of data.csv. In the clojure spirit 
of simplicity it complects quoting of values with writing to disk. There 
might be different policies for when an api-user wants there values to be 
quoted:

* Quote everything (this can be done by setting :quote? to (constantly true)
* Quote nothing (this can be done by setting :quote? to (constantly false))
* Quote only when necessary (this is the default)
* Quote only the first row (i.e,, header)
* Quote (for example) the first and third column
* etc.

I thought about this a couple of days ago and the best I could come up with 
was to remove quoting from the writing part and have users quote there 
values as a pre-processing step before writing. If that is the way forward 
then there is almost nothing more to do in the writing part of the 
data.csv, e.g., you could just as well write

(with-open [w (io/writer some-file)]
  (with-binding [*out* w]
(doseq [row data] 
  (println (string/join , row)))

So It's not entirely clear to me if csv-write is needed at all and instead 
have a few helper functions, for example (quote-string s \'), together with 
a good description of how to use with-binding, doseq, str/join etc. in the 
README file.

Ideas welcome.

Jonas




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