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John Carmack on mutable variables

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498 points azhenley | 1 comments | 31 Oct 25 02:34 UTC | HN request time: 0.284s | source
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anymouse123456 ◴[31 Oct 25 13:50 UTC] No.45771965[source]▶
I completely agree with the assertion and the benefits that ensue, but my attention is always snagged by the nomenclature.

I know there are alternate names available to us, but even in the context of this very conversation (and headline), the thing is being called a "variable."

What is a "variable" if not something that varies?

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ychen306 ◴[31 Oct 25 19:42 UTC] No.45775911[source]▶
I try to avoid this ambiguity by calling such variables "values".
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1. ordu ◴[01 Nov 25 00:26 UTC] No.45778176[source]▶
It leads to a further ambiguity, because "value" is something that is assigned to a variable (or whatever we call it). For example some Rust code:

  let v1 = Vec::new();
  let v2 = v1;
The first line creates value of type Vec and places it into variable v1. The second line moves the value from variable v1 to variable v2. If we rename "variable" to "value" then my description of the code will become unreadable.

If I was as pedantic as the OP, I'd use "lexical binding" instead of "variable". But I'm not sure how it will work with C and C++, because their semantics assumes that a variable has a memory associated with it that can hold a value of a given type. Modern compilers are smarter than that, but still they try hard to preserve the original semantics. The variable in C/C++ is not just a name that ceases to exist after compiler have done its work. It creates a possibility that calling C/C++ variables "lexical bindings" we'll get more pedants accusing us of improper use of words, even if we never change values of those variables.