<div dir="ltr"><div>My maps:first/1 and maps:next/2will be coming when? :-)<br><br></div>Robert<br><br></div><div class="gmail_extra"><br><div class="gmail_quote">On 20 April 2016 at 16:44, Björn-Egil Dahlberg XB <span dir="ltr"><<a href="mailto:bjorn-egil.xb.dahlberg@ericsson.com" target="_blank">bjorn-egil.xb.dahlberg@ericsson.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"><span class="">
On 2016-04-20 16:38, Federico Carrone wrote:<br>
<blockquote type="cite">
<div dir="ltr">It would be awesome to have a a map iterator/map
comprehension.</div>
</blockquote>
<br></span>
Many are of the same opinion. However iterators are not in this
scope. Only API additions to the maps module are.<br>
Efficient iterators are necessary to implement efficient generators
for maps. Efficient maps comprehension is whole other ballgame.<br>
<br>
I will post a PR of maps:take/2 and maps:apply/3,4 later this week.
I'm not sure about apply .. or it's name.<div><div class="h5"><br>
<br>
<br>
<blockquote type="cite"><br>
<div class="gmail_quote">
<div dir="ltr">On Tue, Apr 19, 2016 at 5:30 PM Robert Virding
<<a href="mailto:rvirding@gmail.com" target="_blank">rvirding@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>I missed this thread, but Björn-Egil you know what
I want. :-)<br>
<br>
</div>
maps:first(Map) -> {Key,Value} | error.<br>
</div>
maps:next(Key, Map) -> {Key,Value} | error.<br>
<br>
</div>
</div>
<div dir="ltr">Robert<br>
<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On 13 April 2016 at 15:40,
Björn-Egil Dahlberg XB <span dir="ltr"><<a href="mailto:bjorn-egil.xb.dahlberg@ericsson.com" target="_blank"></a><a href="mailto:bjorn-egil.xb.dahlberg@ericsson.com" target="_blank">bjorn-egil.xb.dahlberg@ericsson.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> There is
currently no (good) way to get out of C-context to
execute some erlang snippet and then get back into
c-context. Traps does this but only in a controlled
manner. I think it is doable though.<br>
<br>
Your proposal of maps_apply/3 is the maps equivalent
of dict:update/3 and sadly that name is already
occupied in maps (it's the equivalent of gb_trees).<br>
<br>
I think we should add it to the API without thinking
about the performance too much. Performance can always
be improved later on.<br>
<br>
Is maps:apply/3 the best name we can think of? I don't
really trust you and naming things. =) update/3,4
would probably have been best but c'est la vie.<span><font color="#888888"><br>
<br>
// Björn-Egil</font></span>
<div>
<div><br>
<br>
<div>On 2016-04-13 13:09, Jesper Louis Andersen
wrote:<br>
</div>
</div>
</div>
<blockquote type="cite">
<div>
<div>
<div dir="ltr">
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Apr 8, 2016
at 8:31 PM, Björn-Egil Dahlberg <span dir="ltr"><<a href="mailto:wallentin.dahlberg@gmail.com" target="_blank">wallentin.dahlberg@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Have you
repeated some code or built your own
private lib to handle certain maps
specific tasks and thought "why isn't
this in the maps module?"</blockquote>
</div>
<br>
</div>
<div class="gmail_extra">One function I like
to have is "apply update via function", and
I implement it somewhat often:<br>
<br>
</div>
<div class="gmail_extra">maps_apply(F, K, Map)
-><br>
</div>
<div class="gmail_extra"> V = maps:get(K,
Map),<br>
</div>
<div class="gmail_extra"> maps:put(K, F(V),
Map).<br>
<br>
</div>
<div class="gmail_extra">But it can be made
much faster in a direct implementation since
I don't have to first pick up the value: I
can apply F when I sit with the value at
hand and thus avoid the "put" lookup path.
It might, however, be nasty to implement
because F is in Erlang-context, whereas the
maps operations are in BIF-context.<br>
</div>
<div class="gmail_extra"><br clear="all">
<br>
-- <br>
<div>J.</div>
</div>
</div>
<br>
<fieldset></fieldset>
<br>
</div>
</div>
<span>
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