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

Fred Youhanaie <>
Fri Feb 21 18:14:43 CET 2014


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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>> 
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