Propose the borrow operator
#2693
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tbkka
reviewed
Feb 15, 2025
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| ```swift | ||
| // Force the value of c to be borrowed. If c is somehow modified during | ||
| // this call, there may be an error at runtime. |
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"error at runtime" here implies that borrows carry runtime costs that do not apply to similar copies. Since most people's mental model seems to be that "borrow" is "pointer to" with no other overhead, that cost likely needs to be called out a little more explicitly.
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Ah. I see you've explored that in the borrows-by-default section at the end.
tbkka
reviewed
Feb 15, 2025
| - *borrows*, which just read the low-level information in the value, or | ||
| - *copies*, which create a new, independent copy of that low-level | ||
| information according to the rules of the type. | ||
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I wonder if there should be a footnote here that points out that "borrow" does not necessarily mean "pointer to." For small items, it's more efficient to "bitwise borrow" by (temporarily) copying the contents.
rjmccall
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