[erlang-questions] IO efficiency

Bjorn Gustavsson <>
Mon May 4 11:58:48 CEST 2009

On Sun, May 3, 2009 at 3:34 AM, Mark Selby <> wrote:
> Hi all,
> I'm using webmachine, and operating over a tree (node, {id, name,
> children = []}).
> As far as output goes, appending recursively to a list seems to make
> sense, as it contains the output in the right order. Just keep a depth
> flag going to achieve indented output.

I am not sure what you currently are doing, but if you are doing something like

PreviousOutput ++ NewStr

you should do


instead to create a deep list. There is usually no need
to flatten the list as most functions that accept strings
also accept deep lists.


Björn Gustavsson, Erlang/OTP, Ericsson AB

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