John Daily macintux

This is not intended to be comprehensive or authoritative, just free online resources I've found valuable while learning more about Erlang.

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Instruction

Doc: http://www.erlang.org/doc/reference_manual/typespec.html

-type square() :: tuple(pos_integer(), pos_integer()).
-type side() :: 'white'|'black'.
-type movefun() :: fun((square(), square(), side()) -> tuple(square(), list(square()))).
-type movedef() :: tuple(atom(), movefun()).

-record(move, { piece,
 start,

I started working on some missing documentation in the Erlang stdlib, and found one particularly confusing rabbit hole.

gen_server.xml

In the documentation for gen_server, I found debug options for start_link which lacked type information:

    Dbg = trace | log | statistics | {logfile,FileName} | {install,{Func,FuncState}}</v>
        SOpts = [term()]

FileName isn't defined, Func and FuncState aren't defined, so I decided to dig into the source to document their types.

Put

API

Starting: https://github.com/basho/riak_kv/blob/1.4.2/src/riak_kv_wm_object.erl#L619
We create a new riak_object and populate the various fields with the headers, metadata supplied by the client.
Big suprise, we eventually call riak_client:put: https://github.com/basho/riak_kv/blob/1.4.2/src/riak_client.erl#L143
If/when the client returns any errors these are handled in handle_common_errors and it is nice to return human readable errors to client :)

Riak_client

Assuming you've created a text file named "ordered" with the PDFs in the sequence you'd like to create:

$ cp /System/Library/Automator/Combine\ PDF\ Pages.action/Contents/Resources/join.py /usr/local/bin/join-pdfs

$ perl -e '$first = <STDIN>; chomp $first; while(<STDIN>) { $index++; $intmdt = "foo$index.pdf"; chomp; system("join-pdfs -o $intmdt $first $_"); $first = $intmdt; }' < ordered

Now you'll have a host of foo.pdf files; the last one is the one you want to rename to something useful, then rm foo*.pdf.

	%%% @author John Daily
	%%% @copyright (C) 2013, John Daily
	%%% @doc
	%%%
	%%% @end
	%%% Created : 3 Aug 2013 by John Daily

	-module(etude51).
	-compile(export_all).

	#!/usr/local/bin/python

	import riak

	Riak = riak.RiakClient(pb_port=10017, protocol='pbc')
	TweetsBucket = Riak.bucket('tweets')

	results = TweetsBucket.get_index("hashtags_bin", "android",
	"androie", return_terms=True)

	#!/usr/local/bin/python

	import riak

	Riak = riak.RiakClient(pb_port=10017, protocol='pbc')
	TweetsBucket = Riak.bucket('tweets')

	results = TweetsBucket.get_index("hashtags_bin", "android",
	"androie", return_terms=False)

	curl -XPOST http://localhost:8098/mapred
	-H"Content-Type: application/json"
	-d '{"inputs":"notifications","query":[{"map":{"language":"erlang","source":"fun(O,_,_) when element(1,O) == r_object -> S=byte_size(term_to_binary(riak_object:get_values(O))), if (S>1048576) -> {ok,C}=riak:local_client(),C:delete(riak_object:bucket(O),riak_object:key(O)),[riak_object:key(O)]; true -> [] end;(_,_,_) -> [] end."}}]}'