[Lasagna] revision to existing concept exercise

[colinleach]

For discussion on the forum

This revision (the most recent of many):

• Rewrites and shortens the introduction.md to meet Exercism guidelines.
• Enforces use of a constant, in place of magic numbers within the code.
• Points the top-level config.sys to the basics concept, instead of 3 older ones.

The old documentation isn't wasted: I moved some to basics/about.md and some to later concepts.

Including the introduction.md.tpl was my mistake. It should probably be removed now we no longer need to combine bits from 3 concepts.

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

If this PR does not affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), please add the following to the merge-commit message which will stops student's tests from re-running. Please copy-paste to avoid typos.

[no important files changed]

For more information, refer to the documentation. If you are unsure whether to add the message or not, please ping @exercism/maintainers-admin in a comment. Thank you!

[colinleach]

Update: one test is failing on Julia 1.6, the current LTS version, but passes on 1.10, the current latest release.

I'll add a guard clause to this test and push a revision.

FYI - 1.6 will probably be dropped by the end of this year, when 1.11 is released and 1.10 becomes LTS.

[BNAndras]

The heading refers to constants but we don't mention constant until later. Perhaps we should introduce what a constant is first and then discuss global variables to show why a constant is preferred.

[colinleach]

Agree

[colinleach]

Extensively reworded. What do you think of the new attempt?

[colinleach]

There's stuff I need to do for the next couple of hours. I'll go through your suggestions again later today and push the changes.

This exercise has been rumbling around for about 5 years. so it would be good to finally get it right!

[colinleach]

Once we agree on the introduction.md here, I'll copy (most of) that to basics.

[colinleach]

I'm trying to keep this first exercise to a minimum, so leaving out implicit multiplication was deliberate. I'm thinking of adding a numbers concept, to deal with this, the various sorts of division, float vs int vs bignum, with a brief mention of rational. Python uses the currency-exchange exercise for this, which may be worth copying.

I haven't made progress on this in the last few days, other than reading around some other tracks. Blame some passing infection and associated fever (the sort of non-specific thing that epidemiologists lump together as ILI (Influenza-Like Infection) and normal people might call "something going around"). Not an aid to clear thinking.

[depial]

I hope you feel better soon!

[BNAndras]

This sentence is a little confusing since we don’t detail what’s not conventional in the next few lines.

[colinleach]

I'll update tomorrow.

[colinleach]

Reading through all this again, months later, I think all the comments are addressed? You can approve when you're happy, but please don't try to merge yet - it will complain about the missing basics concept. I'll try to get that concept (#779) updated and ready to merge first.

[colinleach]

Oops, no. I had (inevitably) missed one requested change.

[depial]

This semi-blank slug seems appropriate for the intentions of the exercise. Everything else also look okay to me

[colinleach]

Yes, an exercise to learn how to add functions is the exception to the rule we discussed earlier!