Sounds good to me. Adding new bang variants are relatively straight-forward. Can you please send a PR? Also, for consistency reasons, can you please change Access.at/1 to become Access.at(index, default \\ nil)?
Thank you! On Mon, Jul 6, 2020 at 12:40 PM Henrik N <hen...@nyh.se> wrote: > Hi, > > I propose adding an `Access.at!` that raises when the given index is out > of bounds, analogous to `Access.key!`. > > The current `Access.at` is not nil safe as discussed in > https://groups.google.com/g/elixir-lang-core/c/CvdW1FsvSf0/m/nlvxkThuEwAJ, > but it's also not analogous to `Access.key!`. > > I specifically want it to raise and point to being out of range (or > whatever the terminology is), rather than causing nil errors further down > the line. > > Current behaviour with `Access.at`: > > # Happy case. Everything exists. > iex(20)> get_in([%{key: "value"}], [Access.at(0), :key]) > "value" > > # Nil safe when index is out of bounds. > iex(21)> get_in([%{key: "value"}], [Access.at(1), :key]) > nil > > # Not nil safe, but error doesn't point to the array index. > iex(22)> get_in([%{key: "value"}], [Access.at(1), Access.key!(:key)]) > ** (RuntimeError) Access.key!/1 expected a map/struct, got: nil > (elixir 1.10.3) lib/access.ex:514: anonymous fn/4 in Access.key!/1 > > I propose something like this behaviour, with `Access.at!`: > > # Happy case – behaves the same. > iex(20)> get_in([%{key: "value"}], [Access.at!(0), :key]) > "value" > > # Explodes. > iex(21)> get_in([%{key: "value"}], [Access.at!(1), :key]) > ** (FooError) index 1 not found in: [%{key: "value"}]. Its highest index > is 0. > > # Explodes in the same way. > iex(22)> get_in([%{key: "value"}], [Access.at(1), Access.key!(:key)]) > ** (FooError) index 1 not found in: [%{key: "value"}]. Its highest index > is 0. > > What do you think? > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elixir-lang-core+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/3a5d1489-dfa5-4c0c-bcd1-5cb85eac2f3fn%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/3a5d1489-dfa5-4c0c-bcd1-5cb85eac2f3fn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. To unsubscribe from this group and stop receiving emails from it, send an email to elixir-lang-core+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4J%3DFZZiwmvAq9ELn2V8tYSmn0R%3D%2Bkt7J9U2HLZWCZDkgA%40mail.gmail.com.
