Elaborate on let bindings
#867
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The original documentation says let bindings are for "repeated use", though one can run ```nix a = 3; a + a ``` just fine without the binding. I think it's more appropriate to explain that `let` limits how far a value's name can reach.
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Welcome to nix.dev, @rayhem! It's great to see new users and contributors joining our community.
Thank you for your suggestions regarding the language tutorial. This section of the site has been crafted with a lot of care, and we're always mindful about maintaining its conciseness to respect our readers' time and attention. While we might not make significant changes to this part right now, your input is still valued and definitely contributes to our ongoing discussions.
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source/tutorials/nix-language.md
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| Attempting to use the value outside of the binding produces an error: | ||
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| ```{code-block} nix | ||
| :class: expression | ||
| a | ||
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| ```{code-block} | ||
| :class: value | ||
| error: undefined variable 'a' | ||
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| at «string»:1:1: | ||
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| 1| a | ||
| | ^ | ||
| ``` | ||
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I feel that this section is a bit redundant, as it's only showing that we can't refer to a variable that hasn't been defined.
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I agree. Do you think it would be appropriate to add commentary along the lines of "let is similar to curly brace scoping in other languages" with information on the similarities and differences? Or is that too much for this section of the tutorial?
Co-authored-by: Henrik <[email protected]>
That only works in the nix repl (although only if you remove the let
a = 3;
in
a + a |
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@rayhem Sorry for chiming in late. Indeed I think it would be too much to go into that sort of depth here. The tutorial is supposed to be a first, deliberately superficial introduction to the most widely used patterns. And yet some readers report it hits them like a wall of text. So while there needs to be a place for these different angles on the language, it would probably need to be a separate tutorial: #579 (And there probably needs to be an even more condensed first glance at the language.) Since the change now seems to have boiled down to almost nothing, I'll close this PR. This is not to dismiss your work! Feel free to add your feedback to other issues as we compile ideas for further tutorials and guides. |
The original documentation says let bindings are for "repeated use", though one can run
just fine without the binding. I think it's more appropriate to explain that
letlimits how far a value's name can reach. This is mentioned later, though, so I'm kind of puzzled on how to improve the language here and make it obvious why a let binding is a useful construction right up front.