[erlang-questions] catch

Fernando Benavides <>
Tue Mar 1 19:01:16 CET 2011


Just use the returned value. Try this:

main([String]) ->
   case length(String) of
       0 -> io:format("~nDid you forget the number?~n~n");
       _ ->
           case catch(list_to_integer(String)) of
               {'EXIT', {badarg,_}} ->
                   io:format("~n~p~n~n",["Arg not Int"]);
               *I ->*
                   Seq=lists:seq(I+1, I+20),
                   lists:foreach(fun(H) -> io:format("#./runcscript ~p
~n",[H]) end, Seq)
           end
   end;
main(_) ->
   io:format("~nDid you forget the number?~n~n").

On Tue, Mar 1, 2011 at 2:46 PM, Wes James <> wrote:

> I have this escript to create a list of output:
>
> main([String]) ->
>        case length(String) of
>                0 -> io:format("~nDid you forget the number?~n~n");
>                _ ->
>                        case catch(list_to_integer(String)) of
>                                {'EXIT', {badarg,_}} ->
>                                        io:format("~n~p~n~n",["Arg not
> Int"]);
>                                _ ->
>                                        I=list_to_integer(String),
>                                        Seq=lists:seq(I+1, I+20),
>                                        lists:foreach(fun(H) ->
> io:format("#./runcscript ~p ~n",[H]) end, Seq)
>                        end
>        end;
>
> main(_) ->
>        io:format("~nDid you forget the number?~n~n").
>
>
> I first tried:
>
> case catch(I=list_to_integer(String)) of
>
> But I think there was an error that I was unsafe.
>
> Is there a way to do a variable assignment to retain a good value so
> you don't have to do the catch then redo it when it is valid? I.e.,
> list_to_ineger will be run twice if it is a valid integer.  Is there a
> way to do this once?
>
> thx,
>
> -wes
>
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-- 
*Fernando Benavides <http://google.com/profiles/greenmellon>*


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