What about `Map.update_if` and `Keyword.update_if`? Benefits: - It's scoped to the data structure that will in fact receive the update (or not) - Closer to the original proposal - Similar to existing functions - Not misleading to broader concepts - May be implemented on other modules by demand in the future
On Monday, June 8, 2020 at 10:19:44 AM UTC-4, José Valim wrote: > > Unfortunately a run_if that has both success and failure branches offers > no benefit to a "if" - so I would suggest to use that instead. > > Furthermore, I wouldn't expect a function called "run_if" to receive (or > return) the first argument if the condition evaluates to false. For > something named run or apply, I would simply expect to return "nil". > > That's why I proposed something along the lines of "update_if", because it > should be clear that the intent is to update/modify the first argument > somehow. > > On Mon, Jun 8, 2020 at 4:13 PM Marcus <[email protected] <javascript:>> > wrote: > >> I like the Map.put_if from the first post. I am not sure if >> run_if/update_if is a good idea because it adds to much "magic", and it >> could lead to the writing of unreadable code. >> If we go with run_if, I think we should have a function for each branch >> (true/false). Something like: >> >> @spec run_if(data, cond, do_fun, else_fun \\ &identity/1) >> when data: term(), >> cond: boolean() | (term() -> boolean()), >> do_fun: (term() -> term()), >> else_fun: (term() -> term()) >> def run_if ... >> >> x = nil >> y = 11 >> z = nil >> >> map >> |> run_if(x != nil, fn m -> Map.put(m, :x, x) end) >> |> run_if(y != nil, fn m -> Map.put(m, :y, y) end) >> |> run_if(fn m -> Map.has_key(m, :a) end, fn m -> Map.put(m, :b) end) >> |> run_if( >> z != nil, >> fn m -> Map.put(m, :z, z) end, >> fn m -> Map.update(m, :missing, :z, fn x -> [:z|x] end) >> ) >> >> -- >> 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 [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/elixir-lang-core/f1e65671-48c9-47cb-9d9f-65a695e41e8co%40googlegroups.com >> >> <https://groups.google.com/d/msgid/elixir-lang-core/f1e65671-48c9-47cb-9d9f-65a695e41e8co%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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/02bfeb72-8e11-4374-8608-ed8e2436a95eo%40googlegroups.com.
