[PATCH] D81667: [RFC, FileCheck] Add precision to format specifier
George Rimar via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 11 03:58:53 PDT 2020
grimar added inline comments.
================
Comment at: llvm/lib/Support/FileCheck.cpp:86
}
}
----------------
grimar wrote:
> thopre wrote:
> > grimar wrote:
> > > Perhaps, it might be simpler just to merge switches and write the logic here as:
> > >
> > >
> > > ```
> > > Expected<std::string> ExpressionFormat::getWildcardRegex() const {
> > > if (Value == Kind::NoFormat)
> > > return createStringError(std::errc::invalid_argument,
> > > "trying to match value with invalid format");
> > > switch (Value) {
> > > case Kind::Unsigned:
> > > if (Precision)
> > > return ("-?([1-9][0-9]*)?[0-9]{" + Twine(Precision) + "}").str();
> > > return std::string("[0-9]+");
> > > case Kind::Signed:
> > > ...
> > > default:
> > > llvm_unreachable("....");
> > > }
> > > }
> > > ```
> > I'm not a big fan of repeating the formatting logic for the Precision case so I've kept that bit as is. What do you think of the result?
> I see 2 possible improvements:
>
> 1) When you have a dedicated `RegexPrefix` variable, you postpone the return and have to add `break`s everywhere.
> If you just do not want to repeat the formatting logic, I'd suggest to add a little helper. E.g:
>
>
> ```
> auto CreatePrecisionRegex = [](StringRef S) -> std::string {
> return (S + Twine(Precision) + "}").str();
> };
>
> switch (Value) {
> case Kind::Unsigned:
> if (Precision)
> return CreatePrecisionRegex("-?([1-9][0-9]*)?[0-9]{");
> return std::string("[0-9]+");
> default:
> llvm_unreachable("ddd");
> }
> ```
>
> The main benefit is that you can return early and avoid having a one more variable.
>
> 2) Perhaps it doesn't make much sence to use `createStringError` for the `default` case? It is unreachable now and can't be tested either (I believe).
>
> So I'd either remove the `if (Value == Kind::NoFormat)` block and handle the error in the `default`, like you initially did,
> or keep it and switch to using `llvm_unreachable` in `default`.
Oh, and for `1)` there is no need to use `-> std::string`:
```
auto CreatePrecisionRegex = [](StringRef S) {
return (S + Twine(Precision) + "}").str();
};
```
Repository:
rG LLVM Github Monorepo
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https://reviews.llvm.org/D81667/new/
https://reviews.llvm.org/D81667
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