[erlang-questions] help me to read proper input from commandline erl

Dave Cottlehuber <>
Fri Feb 21 18:39:10 CET 2014


Depending how complicated your requirements are, consider using

https://github.com/jcomellas/getopt

I'm sure there are other libraries out there, this is the only one I
had bookmarked.

On 21 February 2014 18:14, Fred Youhanaie <> wrote:
> A shorter alternative, though only by just one step, is to use
> erl_parse:parse_term(T) instead of parse_exprs and erl_eval:exprs.
>
> So the steps after the "erl -mylist [1,2,3]." command is
> (note the dot at the end of the argument)
>
> {ok, [[Arg]]} = init:get_argument(mylist).
> {ok, Tokens, _} = erl_scan:string(Arg).
> {ok, List} = erl_parse:parse_term(Tokens).
>
> See example in http://www.erlang.org/faq/how_do_i.html#id53476
>
> Cheers
> Fred
>
>
>
> On 21/02/14 14:41, Matthew Evans wrote:
>>
>> Not sure if there's another way...
>> List = "[1,2,3,4]".
>> {ok,T,_} = erl_scan:string(String++".").
>> {ok,A} = erl_parse:parse_exprs(T).
>> {value,Value,_} = erl_eval:exprs(A, erl_eval:new_bindings()).
>> Value.[1,2,3,4]
>>
>>> Date: Fri, 21 Feb 2014 03:05:53 -0800
>>> From: 
>>> To: 
>>> Subject: [erlang-questions] help me to read proper input from commandline
>>> erl
>>>
>>> hi all,
>>>
>>>        while get runtime command prompt variable via
>>> init:get_argument(name).
>>>
>>>
>>>      i want to get a list . but in that " " are added while getting &
>>> assign
>>> to a varaible
>>>
>>>
>>> % erl -mylist [1,2,3,4]
>>>
>>>> {ok,[[List|_]|_]} = init:get_argument(mylist).
>>>
>>> {ok,[["[1,2,3,4]"]]}
>>>>
>>>> List.
>>>
>>> "[1,2,3,4]"
>>>
>>>
>>>
>>> but expecting O/p as
>>>
>>>> List.
>>>
>>> [1,2,3,4]
>>>
>>>
>>> please help , because of this double qutoes am not able to do Head & Tail
>>> .
>>>
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>> http://erlang.2086793.n4.nabble.com/help-me-to-read-proper-input-from-commandline-erl-tp4655367.html
>>> Sent from the Erlang Questions mailing list archive at Nabble.com.
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>>> erlang-questions mailing list
>>> 
>>> http://erlang.org/mailman/listinfo/erlang-questions
>>
>>
>>
>>
>>
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