[Booleans] new concept #781
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concepts/booleans/about.md
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| Because `5 > 12` is `false`, clearly the combined expression must be `false`. |
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I don't believe we can say the combined expression is clearly false since we haven't introduced why the expression would be false. We also risk reinforcing whatever interpretation the student got from line 85 because they might think Julia stops when it hits a false value regardless of which operator is used so that's what "unambiguous" means.
concepts/booleans/about.md
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| Because `5 > 12` is `false`, clearly the combined expression must be `false`. | ||
| The `1 != 0` expression is not relevant and is never evaluated. |
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1 != 0 isn't evaluated when the left side evaluates to false. It is evaluated if the left side evaluates to true so we can't say it's never evaluated without qualifying that never.
concepts/booleans/introduction.md
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| Parentheses are optional and can make the code easier to read. |
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This should be included under the logical OR section. However, we've already mentioned this in the Boolean logic section so it can be dropped.
concepts/booleans/introduction.md
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| In Julia (and many other programming languages), `&&` has a [higher precedence][operator-precedence] than `||` (in the same way that `*` is applied before `+`). | ||
| This means that `true || false && true` evaluates to `true` because it is parsed as `(true || false) && true`. | ||
| It is common to include explicit brackets anyway so that the reader doesn't need to think about this. |
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| It is common to include explicit brackets anyway so that the reader doesn't need to think about this. | |
| It is common to include explicit parentheses anyway so that the reader doesn't need to think about this. |
Co-authored-by: András B Nagy <20251272+BNAndras@users.noreply.github.com>
Co-authored-by: András B Nagy <20251272+BNAndras@users.noreply.github.com>
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I need to think about this and try again. |
Co-authored-by: András B Nagy <20251272+BNAndras@users.noreply.github.com>
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Your key point is that comparison operators aren't taught till the next concept. I'm a bit less worried about this in One take-home message: don't blindly reuse text from the older exercise drafts, as I did here.. There are reasons why this syllabus hasn't launched. I'll think about this, and try again tomorrow. |
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I did a major rewrite (essentially from scratch) of both Markdown files, in response to the all-too-valid criticisms from @BNAndras. Further comments welcome, from anyone. |
| Only expressions which evaluate to `true` or `false` will be treated as a `Bool`. | ||
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| Specifically, empty arrays or strings will *not* be interpreted as `false`. | ||
| There must be an appropriate test such as `isempty()` if you want special handlind for empty values. |
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| There must be an appropriate test such as `isempty()` if you want special handlind for empty values. | |
| There must be an appropriate test such as `isempty()` if you want special handling for empty values. |
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| These operators will be familiar to users of many other languages, though *not* Python. |
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This sentence is confusing. and and or exist in other languages. Perhaps we say the operators and these concepts should be familiar coming from other languages but they might have different names there.
For discussion on the forum.
This concept draft borrows heavily from
exercises/concept.wip/.docs/introduction.md, with some edits and new additions. It pairs withannalyns-infiltration.