Hey All, I'd have posted this to clojure-dev if I wasn't still pending access (I'm sure the queue is large, so no worries), but, the fine folks in IRC said here would be appropriate as well.
This morning I was looking to do some command line parsing and went with
clojure.contrib.command_line that chouser wrote. It's a great library, and
works as expected, but command line arguments are inherently typed in
certain cases, say a port number, which is one thing I was passing via the
command line.
So, I've attached a patch that makes it possible to specify a validation
function, which either throws an Exception or returns nil, in the case the
the attribute is not valid, or returns a coerced value if it is.
Here's an example:
user=> (pp (make-map ["--port" "80" "--ok-if-foo" "foo"]
[['port 'p "the port" 80 #(Integer/parseInt %)]
['ok-if-foo 'o "only ok if foo" #(= "foo" %)]]))
{"ok-if-foo" true, ;;; coerced to true
"" [],
:cmdspec
[[port
p
"the port"
80
#<user$eval1281$fn__1282 user$eval1281$fn__1...@7991ba7>]
[ok-if-foo
o
"only ok if foo"
#<user$eval1281$fn__1284 user$eval1281$fn__1...@6600b925>]],
"port" 80 ;;; coerced to integer 80
}
However, if we swap the arguments around --port foo --ok-if-foo 80, you see
we get an "Invalid value for port"
user=> (make-map ["--port" "foo" "--ok-if-foo" "80"]
[['port 'p "the port" 80 #(Integer/parseInt %)]
['ok-if-foo 'o "only ok if foo" #(= "foo" %)]])
java.lang.Exception: Invalid value for port (NO_SOURCE_FILE:0)
And of course, it's still backwards compatible:
user=> (pp (make-map ["--verbose" "--port" "80"]
[['verbose? 'v? "verbose" false]
['port 'p "port to listen on"]]))
{"port" "80",
"verbose?" true,
"" [],
:cmdspec [[verbose? v? "verbose" false] [port p "port to listen on"]]}
I've attached the patch, and would love suggestions, feedback, criticism,
etc.
Thanks,
Andrew
--
http://www.apgwoz.com
--
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
contrib.command-line.validation.diff
Description: Binary data
