[erlang-questions] new float_to_list/2 BIF - critique wanted

Gleb Peregud <>
Sun May 3 17:31:23 CEST 2009

On Sun, May 3, 2009 at 17:15, Per Melin <> wrote:
> Gleb Peregud:
> Yes! I cannot overstate how much I would appreciate a BIF like this.
> Dealing with large amounts of financial instrument information, where
> response times and latency must be low, the lack of a fast usable
> float_to_list is a huge pain.

I feel the same way with GIS data, where coordinates are stored as
floats. Example:
mochinum:digits/1 gave me throughput of 5kBps
io_lib:format/2 gave c.a. 300kBps
float_to_list/1 gave me c.a. 450kBps, but HUGE overhead in size of
resulting JSON
float_to_list/2 gave me c.a. 500kBps with optimal size of the
resulting coordinates representation in JSON

I'm waiting for critique, so the chance of it being accepted is as
high as possible :) Currently I'm concerned about probably excessive
buffer sizes and the way of creating format string "%.NNe", where NN
is precision. How can it be improved?

The implementation is stored here:

Gleb Peregud

Every minute is to be grasped.
Time waits for nobody.
-- Inscription on a Zen Gong

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