Add list slice#706
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| <dfn export for=list/slice><var>to</var></dfn> (default |list|'s <a for=list>size</a>), is to create a new | ||
| <a>list</a> |slice|, of the same designation, and <a for=list>append</a> each | ||
| <a for=list>item</a> of |list|, where the index is greater than or equal to |from| and less than | ||
| |to|, to |slice|, maintaining order. |
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I think we should make this a list of steps for clarity. That way we can also assert the obvious things about from and to.
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Yeah that's fair.
Are you ok with clone being defined in terms of slice?
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Yeah that seems good. Always nice to have fewer fundamental primitives.
| <li><p>If |from| is less than 0, then set |from| to 0. | ||
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| <li><p>If |to| is greater than |list|'s <a for=list>size</a>, then set |to| to |list|'s <a for=list>size</a>. |
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I felt this was preferable to asserting. It means, like in JS, you can slice from 0 to 100 to 'crop' a list to maximum of 100 items.
['foo'].slice(0, 100); // does not throw
| <li><p>If |from| is less than 0, then set |from| to 0. | ||
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| <li><p>If |to| is greater than |list|'s <a for=list>size</a>, then set |to| to |list|'s <a for=list>size</a>. |
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Is this needed for specifications? I might not be considering all scenarios that well, but I was assuming we'd just want to require both of these to be within bounds of the list.
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I don't mind turning these into asserts. I was just copying how JS array.slice() works.
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Let's start out with a very strict contract then until we hit cases where it would make sense to not be so strict.
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Cheers! |
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For whatwg/html#12345.
I also changed the definition of clone, since it's just a slice with default args.