Comment by bpshaver
Comment by bpshaver a day ago
Who is out here mixing types in a list anyway?
Comment by bpshaver a day ago
Who is out here mixing types in a list anyway?
If your language obstructs heterogeneous lists your programs will tend to lack them. Look for classes containing multiple hashtables from the same strings to different object types as a hint that they're missed.
Whether that's a feature is hard to say. Your language stopped you thinking in those terms, and stopped your colleagues from doing so. Did it force clarity of thought or awkward contortions in the implementation? Tends to depend on the domain.
Heterogeneity is easily achieved in statically typed languages via sum types.
The json module returns heterogenous dicts.
They, uh, still aren't wrong hah.
Tell me again why we somehow standardized on sending the equivalent of JSObject.toString() for everything? Especially when "standardized" isn't
Why would I want to do that? I'm rarely ingesting arbitrary JSON. Rather I'm designing my data structures in a sensible way and then maybe serializing them to JSON. Just because JSON can represent heterogenous lists doesn't mean it is a good idea to use heterogenous lists in my programs.
I often find myself mixing Nones into lists containing built-in types when the former would indicate some kind of error. I could wrap them all into a nullable-style type, but why shouldn't the interpreter implicitly handle that for me?
An example related to JSON content is HTML content. I have a Python library that represents all of the standard HTML tags as a family of classes. It is like a lightweight DOM on the server side, and has resulted in a web server that does not use string based templating at all. It lets me construct trees of HTML completely in Python and then render them out with everything correctly escaped. I can also parse HTML into trees and manipulate them as I please (for e.g. scraping tasks and document transforms). It is all strongly typed using mypy and I adhere to the strictest generic typing I can manage.
Each node has a list of children, and the element type is `str|HtmlNode`. I find this vastly easier to use than the LXML ETree api, where nodes have `text` and `tail` attributes to represent interleaved text.
Interestingly, the LXML docs promote their design as follows: > he two properties .text and .tail are enough to represent any text content in an XML document. This way, the ElementTree API does not require any special text nodes in addition to the Element class, that tend to get in the way fairly often (as you might know from classic DOM APIs). https://lxml.de/tutorial.html#elements-contain-text
It could be a simple matter of taste! But I suspect that the difference between what they are describing as "classic DOM" vs what I am doing is that they are referring to experience with C/C++/Java libraries circa 2009 that had much less convenient dynamic type introspection. The "get in the way fairly often" reminds me of how verbose it is to deal with heterogenous data in C/C++/ObjC. In ObjC for example, you could have an array mixing NSString with other NSObject subclasses, but you had to do work to type it correctly. If you wanted numbers in there you had to use NSNumber which is an annoying box type that you never otherwise use. And ObjC was considered very dynamic in its day!
I have long felt that the root of much evil was the overbearing distinction between primitive and object types in C++/Java/Objective-C.
All of this is a long way of saying, I think "how to deal with heterogenous lists of stuff" is a huge question in language design, library design, and the daily work of programming. Modern languages have by no means converged on a single way to represent varying types of elements. If you want to create trees of stuff, at some level that is "mixing types in a list" no matter how you might try to encode it. Just food for thought!
To quote the Zen of Python:
Explicit is better than implicit.
Readability counts.
parsing json is roughly of the type:
type Json = None | bool | float | str | dict[str, Json] | list[Json]
you might have similar situations for configs e.g. float | str for time in seconds or a human readable time string like "30s" etc.
given how fundamental such things are I'm not sure if there will be any larger projects (especially wrt. web servers and similar) which are compatible with this
also many commonly used features for libraries/classes etc. are not very likely to work (but idk. for sure, they just are very dynamic in nature)
so IMHO this seems to be more like a python-like language you can use for idk. some since computations and similar then a general purpose faster python