4 ms·

Is that just because F# is a typed language? My personal experience has been that it's a pain to implement this as soon as you have strong typing and try to av

by gyulai 3y ago

Is that just because F# is a typed language? My personal experience has been that it's a pain to implement this as soon as you have strong typing and try to avoid "unsafe" casts. For example, in modern Java, if you have some kind of a Container<T> over elements of type T, and a matching ContainerIterator<T>, you will want some way in each of the type declarations to refer to the other type declaration, so you need cyclical imports. If you look at it through the lens of a dynamically-typed language like Python 3.4 or Lua, the problem just disappears. This is the case to a lesser extent even for Java before it had generics, and collections were just collections of Object, and you used "unsafe" casts all the time. I am finding this practice not the slightest bit limiting in Lua, nor do I get the feeling that the readability of my code suffers in any way at all. (Rather the contrary, as I've pointed out before).

electroly 3y ago
I wouldn't blame the static type system; this is more of a language design decision of its own. IMO, F# does it this way because ML did it this way. I think it's more of a cultural norm than a technical decision. There is a certain theoretical purity to requiring ordered declarations across a whole project. It's valuable to compare F# against C++ here. F# and C++ both require ordered declarations within a file (while C# and Java do not), but F# requires the files themselves to be ordered, too, while C++ does not. Both are statically typed languages. C++ avoids requiring a file-level order by defining file-level compilation units and a system for importing and exporting symbols between compilation units to allow each file to be processed separately with the imports/exports resolved during a final linking phase. There's complexity involved in accomplishing this. F# has not done it; an F# project is the same as concatenating all of the source files together, and thus declarations must be ordered across files just like they are within a file.

by gyulai 3y ago

electroly 3y ago

I wouldn't blame the static type system; this is more of a language design decision of its own. IMO, F# does it this way because ML did it this way. I think it's more of a cultural norm than a technical decision. There is a certain theoretical purity to requiring ordered declarations across a whole project. It's valuable to compare F# against C++ here. F# and C++ both require ordered declarations within a file (while C# and Java do not), but F# requires the files themselves to be ordered, too, while C++ does not. Both are statically typed languages. C++ avoids requiring a file-level order by defining file-level compilation units and a system for importing and exporting symbols between compilation units to allow each file to be processed separately with the imports/exports resolved during a final linking phase. There's complexity involved in accomplishing this. F# has not done it; an F# project is the same as concatenating all of the source files together, and thus declarations must be ordered across files just like they are within a file.