Module Calculations: Concat example leads to Enum.map_join/3 error (separator argument missing)

I have the following 3 resources:

App.Api.Brand
App.Api.Category
App.Api.Family

App.Api.Brand
App.Api.Category
App.Api.Family

Family belongs_to a Brand and a Category. Brand and Category each have a :name string attribute. Within Family I have two aggregates:

  aggregates do
    first :brand_name, :brand, :name
    first :category_name, :category, :name
  end

  aggregates do
    first :brand_name, :brand, :name
    first :category_name, :category, :name
  end

...and one calculation for :tagline that should concatenate the two aggregates above.

  calculations do
    calculate :tagline, :string, {Concat, keys: [:brand_name, :category_name]} do
      argument :separator, :string, constraints: [allow_empty?: true, trim?: false]
    end
  end

  calculations do
    calculate :tagline, :string, {Concat, keys: [:brand_name, :category_name]} do
      argument :separator, :string, constraints: [allow_empty?: true, trim?: false]
    end
  end

The Concat code is in lib/api/calculations.ex. I have a record f of type App.Api.Family, associated with a Brand and a Category record. In IEx:

iex(36)> f |> App.Api.load(:tagline)
** (FunctionClauseError) no function clause matching in Enum.map_join/3    
    
    The following arguments were given to Enum.map_join/3:
    
        # 1
        [:brand_name, :name, :category_name]
    
        # 2
        nil
    
        # 3
        #Function<1.6122725/1 in Concat.calculate/3>
    
    Attempted function clauses (showing 1 out of 1):
        
        def map_join(enumerable, joiner, mapper) when is_binary(joiner)

iex(36)> f |> App.Api.load(:tagline)
** (FunctionClauseError) no function clause matching in Enum.map_join/3    
    
    The following arguments were given to Enum.map_join/3:
    
        # 1
        [:brand_name, :name, :category_name]
    
        # 2
        nil
    
        # 3
        #Function<1.6122725/1 in Concat.calculate/3>
    
    Attempted function clauses (showing 1 out of 1):
        
        def map_join(enumerable, joiner, mapper) when is_binary(joiner)

Alternatively:

iex(36)> f |> App.Api.load(tagline: [separator: " - "])
** (Protocol.UndefinedError) protocol String.Chars not implemented for #Ash.NotLoaded<:aggregate> of type Ash.NotLoaded (a struct). This protocol is implemented for the following type(s): Ash.CiString, Atom, BitString, Date, DateTime, Decimal, Float, Hex.Solver.Assignment, Hex.Solver.Constraints.Empty, Hex.Solver.Constraints.Range, Hex.Solver.Constraints.Union, Hex.Solver.Incompatibility, Hex.Solver.PackageRange, Hex.Solver.Term, Integer, List, NaiveDateTime, Phoenix.LiveComponent.CID, Postgrex.Copy, Postgrex.Query, Time, URI, Version, Version.Requirement

iex(36)> f |> App.Api.load(tagline: [separator: " - "])
** (Protocol.UndefinedError) protocol String.Chars not implemented for #Ash.NotLoaded<:aggregate> of type Ash.NotLoaded (a struct). This protocol is implemented for the following type(s): Ash.CiString, Atom, BitString, Date, DateTime, Decimal, Float, Hex.Solver.Assignment, Hex.Solver.Constraints.Empty, Hex.Solver.Constraints.Range, Hex.Solver.Constraints.Union, Hex.Solver.Incompatibility, Hex.Solver.PackageRange, Hex.Solver.Term, Integer, List, NaiveDateTime, Phoenix.LiveComponent.CID, Postgrex.Copy, Postgrex.Query, Time, URI, Version, Version.Requirement

What am I doing wrong? 😵‍💫

21 Replies

waseigoOP•3y ago

@Zach Daniel, any ideas?

ZachDaniel•3y ago

Sorry, forgot to come back to this 🤔 lemme take a look at the builtin calculation fixed in main

waseigoOP•3y ago

Do you mean it was a bug that is now fixed in the trunk?

ZachDaniel•3y ago

Yeah I just pushed a fix

waseigoOP•3y ago

aha, thank you!

ZachDaniel•3y ago

You can use main, or you can make the dependencies explicit via:

    calculate :tagline, :string, {Concat, keys: [:brand_name, :category_name]} do
      argument :separator, :string, constraints: [allow_empty?: true, trim?: false]
      load [:brand_name, :category_name] # <- normally you want the calculation to do this, but this should fix your bug w/o needing to use the main branch if you don't want to
    end

    calculate :tagline, :string, {Concat, keys: [:brand_name, :category_name]} do
      argument :separator, :string, constraints: [allow_empty?: true, trim?: false]
      load [:brand_name, :category_name] # <- normally you want the calculation to do this, but this should fix your bug w/o needing to use the main branch if you don't want to
    end

waseigoOP•3y ago

I looked at github and saw that the fix is for lib/ash/resource/calculation/concat.ex -- does this mean that Ash already provides the Concat module, and that my lib/api/calculations.ex is not required?

waseigoOP•3y ago

I guess it does, huh? https://github.com/ash-project/ash/blob/main/lib/ash/resource/calculation/builtins.ex

GitHub

ash/builtins.ex at main · ash-project/ash

A declarative and extensible framework for building Elixir applications. - ash/builtins.ex at main · ash-project/ash

ZachDaniel•3y ago

oh I thought you were using it 😆

waseigoOP•3y ago

I guess my calculations.ex was never loaded because anyway I never imported it No, I just copied the Concat module from the Getting Started guide

ZachDaniel•3y ago

Ohhh okay well I should fix that too then But yes, we do have a built in concat that I just fixed Just pushed up a fix for that guide, the docs will be fixed on the next release

waseigoOP•3y ago

thx! Indeed, I just saw that actually I was using the guide's Concat

ZachDaniel•3y ago

In your custom concat you can add def load/3 and return the fields required if you'd rather do that than use ash's main branch, your call 😄

waseigoOP•3y ago

I'm trying this out. My calculations.ex file contains defmodule Concat ... from the latest commit https://github.com/ash-project/ash/commit/2c8b07fd0b9a7b3b0bb8a5886f1255c6ef91ba33 (so it now includes the load/3 part). My resource contains a calculation:

    calculate :tagline, :string, {Concat, keys: [:brand_name, :category_name]} do
      argument :separator, :string, constraints: [allow_empty?: true, trim?: false]
      load [:brand_name, :category_name] 
    end

    calculate :tagline, :string, {Concat, keys: [:brand_name, :category_name]} do
      argument :separator, :string, constraints: [allow_empty?: true, trim?: false]
      load [:brand_name, :category_name] 
    end

In IEx (where f is a record of type App.Api.Family:

iex(18)> f |> Api.App.load!(:tagline)
** (FunctionClauseError) no function clause matching in Enum.map_join/3    
    
    The following arguments were given to Enum.map_join/3:
    
        # 1
        [:brand_name, :category_name]
    
        # 2
        nil
    
        # 3
        #Function<1.65930104/1 in Concat.calculate/3>
    
    Attempted function clauses (showing 1 out of 1):
    
        def map_join(enumerable, joiner, mapper) when is_binary(joiner)
    
    (elixir 1.14.0) lib/enum.ex:1753: Enum.map_join/3
    (elixir 1.14.0) lib/enum.ex:1658: Enum."-map/2-lists^map/1-0-"/2
    (ash 2.6.0) lib/ash/actions/read.ex:1663: anonymous fn/7 in Ash.Actions.Read.calculation_request/11
    (ash 2.6.0) lib/ash/engine/engine.ex:468: anonymous fn/2 in Ash.Engine.run_iteration/1
    (ash 2.6.0) lib/ash/engine/engine.ex:623: Ash.Engine.start_pending_tasks/1
    (ash 2.6.0) lib/ash/engine/engine.ex:273: Ash.Engine.run_to_completion/1
    (ash 2.6.0) lib/ash/engine/engine.ex:202: Ash.Engine.do_run/2
    (ash 2.6.0) lib/ash/engine/engine.ex:141: Ash.Engine.run/2
    (ash 2.6.0) lib/ash/actions/read.ex:170: Ash.Actions.Read.do_run/3
    (ash 2.6.0) lib/ash/actions/read.ex:90: Ash.Actions.Read.run/3
    (ash 2.6.0) lib/ash/api/api.ex:947: Ash.Api.load/4
    (ash 2.6.0) lib/ash/api/api.ex:921: Ash.Api.load!/4

iex(18)> f |> Api.App.load!(:tagline)
** (FunctionClauseError) no function clause matching in Enum.map_join/3    
    
    The following arguments were given to Enum.map_join/3:
    
        # 1
        [:brand_name, :category_name]
    
        # 2
        nil
    
        # 3
        #Function<1.65930104/1 in Concat.calculate/3>
    
    Attempted function clauses (showing 1 out of 1):
    
        def map_join(enumerable, joiner, mapper) when is_binary(joiner)
    
    (elixir 1.14.0) lib/enum.ex:1753: Enum.map_join/3
    (elixir 1.14.0) lib/enum.ex:1658: Enum."-map/2-lists^map/1-0-"/2
    (ash 2.6.0) lib/ash/actions/read.ex:1663: anonymous fn/7 in Ash.Actions.Read.calculation_request/11
    (ash 2.6.0) lib/ash/engine/engine.ex:468: anonymous fn/2 in Ash.Engine.run_iteration/1
    (ash 2.6.0) lib/ash/engine/engine.ex:623: Ash.Engine.start_pending_tasks/1
    (ash 2.6.0) lib/ash/engine/engine.ex:273: Ash.Engine.run_to_completion/1
    (ash 2.6.0) lib/ash/engine/engine.ex:202: Ash.Engine.do_run/2
    (ash 2.6.0) lib/ash/engine/engine.ex:141: Ash.Engine.run/2
    (ash 2.6.0) lib/ash/actions/read.ex:170: Ash.Actions.Read.do_run/3
    (ash 2.6.0) lib/ash/actions/read.ex:90: Ash.Actions.Read.run/3
    (ash 2.6.0) lib/ash/api/api.ex:947: Ash.Api.load/4
    (ash 2.6.0) lib/ash/api/api.ex:921: Ash.Api.load!/4

GitHub

docs: add load/3 to calculation docs · ash-project/ash@2c8b07f

ZachDaniel•3y ago

oh 🤔 I think your separator is nil actually

      argument :separator, :string, constraints: [allow_empty?: true, trim?: false], default: ""

      argument :separator, :string, constraints: [allow_empty?: true, trim?: false], default: ""

waseigoOP•3y ago

I thought this was allowed due to allow_empty?: true

ZachDaniel•3y ago

allow_empty? prevents the type from turning "" into nil but if no separator is supplied, it will be nil

waseigoOP•3y ago

Ah so I should always pass a separator?

ZachDaniel•3y ago

Or set default: "" on the separator argument and allow_nil?: false

      argument :separator, :string do
        constraints [allow_empty?: true, trim?: false]
        allow_nil? false
        default ""
      end

      argument :separator, :string do
        constraints [allow_empty?: true, trim?: false]
        allow_nil? false
        default ""
      end

is probably what you want I'll update the example

waseigoOP•3y ago

Excellent, works now! 🥳

ZachDaniel•3y ago

🥳

Gaming

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Module Calculations: Concat example leads to Enum.map_join/3 error (separator argument missing)

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