Add new concept `mapsets` and concept exercise `gotta-snatch-em-all` by jiegillet · Pull Request #1578 · exercism/elixir

jiegillet · 2025-06-16T00:17:26Z

This PR add new concept and concept exercise, both forked from the Elm track.

Full disclosure, I used AI (via Cursor) to help translate from one language to the other, and event though I combed through everything and edited a lot of things, it was a huge time saver.

There might be stylistic differences between tracks that I'm blind to, I'm happy to change anything.

The CI is expected to fail until the about.md is finalized, then I'll copy it to introduction.md (let me know if you think some parts should be cut down) and use the generator to add the intro file to the exercise.

github-actions · 2025-06-16T00:17:37Z

Thank you for contributing to exercism/elixir 💜 🎉. This is an automated PR comment 🤖 for the maintainers of this repository that helps with the PR review process. You can safely ignore it and wait for a maintainer to review your changes.

Based on the files changed in this PR, it would be good to pay attention to the following details when reviewing the PR:

General steps
- 🏆 Does this PR need to receive a label with a reputation modifier (x:size/{tiny,small,medium,large,massive})? (A medium reputation amount is awarded by default, see docs)
Any exercise changed
- 👤 Does the author of the PR need to be added as an author or contributor in <exercise>/.meta/config.json (see docs)?
- 🔬 Do the analyzer and the analyzer comments exist for this exercise? Do they need to be changed?
- 📜 Does the design file (<exercise>/.meta/design.md) need to be updated to document new implementation decisions?
Concept exercise changed
- 🌲 Do prerequisites and practices in config.json need to be updated?
- 📖 Does the concept introduction provide all necessary information to solve this exercise?
Concept exercise tests changed
- ⚪️ Are all tests un-skipped?
- 🔢 Are all tests annotated with @tag task_id?
- 🐈 Can all tests be understood by reading the test's block only (e.g. no module attributes, no setup functions)?
Concept changed
- 👤 Does the author of the PR need to be added as an author or contributor in <concept>/.meta/config.json (see docs)?
- 📖 Does the concept introduction provide all necessary information to solve this exercise?

Automated comment created by PR Commenter 🤖.

angelikatyborska

Excellent exercise, very good about.me, I had no trouble solving it and learned new things 🙌

angelikatyborska · 2025-06-30T14:53:05Z

+- Use [this `MapSet` function][put]
+- Use [that `MapSet` function][member]


Nitpick: It would be nice if there was a better indicator of the difference between those two functions than just "this" and "that". Maybe describing briefly their purpose, like the other links? "To add card to a collection...", "To check whether...".

(Same nitpick about step 5 hints)

angelikatyborska · 2025-06-30T14:55:16Z

+You cannot trade a card you don't have, and you shouldn't trade a card for one that you already have.
+
+Implement `trade_card`, that takes two cards to trade (yours and theirs) and your current collection.
+The return value is a tuple of two values: a `Bool` stating if the trade is possible and worth doing, and the collection you would end up with if you did the trade (even if it's not actually possible).


Nitpick: Bool is a description for the boolean type that I would expect in an object-oriented programming language that literally has a class called Bool.

Suggested change

The return value is a tuple of two values: a `Bool` stating if the trade is possible and worth doing, and the collection you would end up with if you did the trade (even if it's not actually possible).

The return value is a tuple of two values: a boolean stating if the trade is possible and worth doing, and the collection you would end up with if you did the trade (even if it's not actually possible).

Nice catch, it's a leftover from the Elm instructions, where Bool is a type.

angelikatyborska · 2025-06-30T15:00:20Z

+Implement `new_collection`, which transforms a card into a collection.
+
+```elixir
+new_collection("Newthree")


I think in all Elixir concept exercises, we demo the function calls using the module name too

Suggested change

new_collection("Newthree")

GottaSnatchEmAll.new_collection("Newthree")

angelikatyborska · 2025-06-30T15:07:31Z

+
+```elixir
+MapSet.new()
+# => MapSet.new([])


I had to do a double-take to believe that this is how the REPL prints that value 😂

I think it used to be something like #MapSet<> or whatever, but they've been moving away from these notations to things that you can copy/paste. In that sense, this is the best way to represent sets :)

That's so clever! I've always been annoyed at those # things that I couldn't copy-paste. I think they showed up most often for Ecto structs.

angelikatyborska · 2025-06-30T15:08:43Z

+          "pattern-matching",
+          "booleans"
+        ],
+        "status": "beta"


Lol, there are concept exercises are in "beta"? Maybe we should just make all of the "active"

Co-authored-by: Angelika Cathor <angelikatyborska@fastmail.com>

jiegillet · 2025-07-05T04:42:13Z

very good about.me

Sorry, but this was not about you, it was about sets! 🤣

I'm glad you like the PR, thanks for the review, I've addressed your comments in the relevantly named commits.

angelikatyborska

🚢

Add new concept mapsets and concept exercise gotta-snatch-em-all

7cb0fe1

jiegillet added 4 commits June 21, 2025 10:41

Merge branch 'main' into jie-mapset

6e03b9f

tweak about, hints and design

cd560ba

add mapsets to exercises practices and prerequisites

4988a9f

MapSet.split_with was added in Elixir 1.15

a271179

jiegillet marked this pull request as ready for review June 21, 2025 03:23

angelikatyborska reviewed Jun 30, 2025

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jiegillet and others added 6 commits July 5, 2025 12:32

Update exercises/concept/gotta-snatch-em-all/.docs/instructions.md

74e724f

Co-authored-by: Angelika Cathor <angelikatyborska@fastmail.com>

remove all beta exercises

d6269d3

better hint descriptions

2829b9e

fully qualify functions in intructions

2a372e2

Bool -> boolean

2f4f915

cleanup and generate exercise intro

01c1b53

jiegillet mentioned this pull request Jul 5, 2025

Write analysis for concept exercise gotta-snatch-em-all exercism/elixir-analyzer#450

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angelikatyborska approved these changes Jul 5, 2025

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angelikatyborska merged commit 64d675e into main Jul 5, 2025
9 checks passed

angelikatyborska deleted the jie-mapset branch July 5, 2025 06:21

		- Use [this `MapSet` function][put]
		- Use [that `MapSet` function][member]

	The return value is a tuple of two values: a `Bool` stating if the trade is possible and worth doing, and the collection you would end up with if you did the trade (even if it's not actually possible).
	The return value is a tuple of two values: a boolean stating if the trade is possible and worth doing, and the collection you would end up with if you did the trade (even if it's not actually possible).

	new_collection("Newthree")
	GottaSnatchEmAll.new_collection("Newthree")

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jiegillet commented Jul 5, 2025

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jiegillet commented Jun 16, 2025 •

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