elixir

问题 I'm tying to make an API where an anonymous function are composed from macros, e.g. transform [x, y], do: x + y transform x, do: x should use the transform head and body[:do] as the heads and bodies for an anonymous function. For example, the above macro calls The example above should be collected into: fn [x, y] -> x + y; x -> x end With unquote fragments it's easy to create new named function def s, but not new anonymous functions: iex> val = 1 iex> fn() -> unquote(val) end ** (CompileError

问题 Let's say I have a map that looks like this An organization has an array of properties and the properties has an array of "access_tokens" organization = %{ name: "Org", properties: [ %{ name: "prop1", access_tokens: [%{id: "at-1", name: "one-1"}, %{id: "at-2", name: "one-2"}] }, %{ name: "prop2", access_tokens: [%{id: "at-3", name: "two-1"}, %{id: "at-4", name: "two-2"}] } ] } Now I have this map, for one particular access token, the id for this one matches one of the access tokens for the

问题 So I have a phoenix project I'm using as a test app of sorts. If I want to use a local version of elixir source code that I'm using (and making changes on), how do I tell phoenix to use it? I also want to be able to use "iex -S mix" with it. The below elixir: ["~> 1.6.0-dev", path: '/my/local/path/to/elixir'] does not work, but it's what I'm trying to do. I already tried adding the below and I get a syntax error. Adding elixir to the dependencies (in the def deps function) didn't seem to do

问题 We are using SeaweedFS which is a file system to store (image) files, It works as a rest api. We are trying to move data from one server to another. there are a few levels of data directories. The basic pattern through which an image is stored is http://{server}:8888/ballymore-project-wave/snapshots/recordings/{year}/{month}/{day}/{hour}/00_00_000.jpg Each level of the directory has its own return, in form of JSON such as { "Path": "/ballymore-project-wave/snapshots/recordings/", "Files":

问题 In the book 'Elixir in Action', one of the examples has a function that is tripping up my understanding of pattern matching: def add_entry( %TodoList{entries: entries, auto_id: auto_id} = todo_list, entry ) do entry = Map.put(entry, :id, auto_id) new_entries = HashDict.put(entries, auto_id, entry) %TodoList{todo_list | entries: new_entries, auto_id: auto_id + 1 } end The first parameter, %TodoList{entries: entries, auto_id: auto_id} = todo_list , the book explains "...Furthermore, you keep

问题 map_set = MapSet.new() Enum.each(filtered_list, fn x -> map_set = MapSet.put(MapSet.new(map_set),x) Here filtered_list is a list containing string but when I am printing map_set it is returning an empty set. Why? 回答1: Your code is equivalent to this this: map_set = MapSet.new() Enum.each(filtered_list, fn x -> other = MapSet.put(MapSet.new(map_set), x) end) The map_set you assign to inside the enum is a local variable, it's not related to the map_set outside the enum. It may as well be called

问题 Elixir 1.0, Erlang 17.3 on Windows 7 x64. I type this code: l = "[9,0]" s = String.strip(l,"[") And I get this: ** (FunctionClauseError) no function clause matching in String.lstrip/2 (elixir) lib/string.ex:527: String.lstrip("[9,0]", "[") (elixir) lib/string.ex:564: String.strip/2 What am I missing? I also tried s = String.strip(l,",") and same error. Also tried s = String.strip(l,'[') same error. What am I missing? 回答1: You want to pass a character to String.strip/2 : s = String.strip(l, ?[

问题 My sample query is as below: %{ "query" => """ query getPerson( $name: String! ){ getPerson(name: $name) { id col1 col2 col3 col3 } } """, "variables" => %{ "name" => "person_name", } } I want to select the fields dynamically. For example, for one query I just need id, col1, col2 but for another query id, col1, col3 and so on. How do I use variable for fields? Below is what I try which is not correct. %{ "query" => """ query getPerson( $name: String! ){ getPerson(name: $name) { $fields } } ""

问题 I'm building an app in Elixir on top of the Phoenix Framework that has a piece of functionality around collecting data from the Spotify API and persisting it into a PostgreSQL 9.4 database for quick access. I'm having trouble with updating existing table rows that use embeds_many . I have Track and AlbumArt Ecto models that looks like this: defmodule CoolApp.Track do use CoolApp.Web, :model alias CoolApp.AlbumArt alias CoolApp.Repo alias CoolApp.Track schema "tracks" do field :sid, :string

问题 I'm trying to set up web sockets to go through Nginx to a Phoenix app but keep getting a 403 error. Can anyone advise the correct configuration to make this work in production - development env is fine. My Nginx conf: upstream phoenix { server 127.0.0.1:4000 max_fails=5 fail_timeout=60s; } server { server_name <app-domain>; listen 80; location / { allow all; # Proxy Headers proxy_http_version 1.1; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $http_host;