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Changes that make this macro easier to read.
- `DepKindDefs` is an enum that is used purely to generate a list of
ascending numbers at compile time, to implement the functions within
`dep_kinds`. This commit replaces it with a `${index()}` macro
metavar. (The comment about u16 data representation doesn't seem
relevant any more.)
- `DEP_KIND_VARIANTS` just counts the number of dep kind variants. It's
implemented via `len()` and a const loop to ensure `DepKindDefs` truly
implements a list of ascending numbers. This commit replaces it with a
`${count(..)}` macro metavar. This commit also renames it to make
clearer it's a count of varants, not an actual list/array/vec of
variants.
- This commit uses `stringify!` more for variant-names-as-strings,
instead of going indirectly via `label_strs`.
rustbot
added
S-waiting-on-review
| pub(super) fn dep_kind_from_label_string(label: &str) -> Result<DepKind, ()> { | ||
| match label { | ||
| $( self::label_strs::$variant => Ok(self::dep_kinds::$variant), )* | ||
| $( stringify!($variant) => Ok(self::dep_kinds::$variant), )* |
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At the time I was thinking that it would be good to reduce the amount of stringify!($name), but I'm not actually very confident about that being the right direction.
So with hindsight, I don't really object to changing it back.
|
For some historical context, the split between I don't know if that has actionable consequences for this PR, but it seems worth bearing in mind as we continue to dismantle |
| pub(crate) const DEP_KIND_VARIANTS: u16 = { | ||
| let deps = &[$(dep_kinds::$variant,)*]; | ||
| let mut i = 0; | ||
| while i < deps.len() { | ||
| if i != deps[i].as_usize() { | ||
| panic!(); | ||
| } | ||
| i += 1; | ||
| } | ||
| deps.len() as u16 | ||
| }; |
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Do we have any other check that the numeric values continue to be dense and ascending from 0?
That's currently still true in the new implementation, but I don't know if there's anything ensuring that it remains true.
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Changes that make this macro easier to read.
DepKindDefsis an enum that is used purely to generate a list of ascending numbers at compile time, to implement the functions withindep_kinds. This commit replaces it with a${index()}macro metavar. (The comment about u16 data representation doesn't seem relevant any more.)DEP_KIND_VARIANTSjust counts the number of dep kind variants. It's implemented vialen()and a const loop to ensureDepKindDefstruly implements a list of ascending numbers. This commit replaces it with a${count(..)}macro metavar. This commit also renames it to make clearer it's a count of varants, not an actual list/array/vec of variants.This commit uses
stringify!more for variant-names-as-strings, instead of going indirectly vialabel_strs.r? @saethlin