Comment by delta_p_delta_x
1 day ago
That is what the parent author means. Static vs dynamic typing is along the dimension of when the type is checked, and strong vs weak typing is a matter of how strongly bound names adhere to types. JS, for instance, is super weak here, you can assign a numerical value to something and in the next line re-assign it to a string, an array, or even a function object.
That's also true of Python, though, which is traditionally considered a strongly typed language.
I'm increasingly convinced that "strong/weak" has no useful meaning. Some people regularly use it interchangeably with "static/dynamic", others use it to vaguely refer to how much casting exists in a language, or how easy it is to transmute a value of one type into a value of a different type. There is no academic definition at all.
Mostly it gets used as a kind of cheap attack - it's like the meme "it's over, I've portrayed you as the soyjack and me as the chad". Good languages are strong, bad languages are weak, so if I say your favourite language has weak typing, and my favourite language has strong typing, then it's clear that my favourite language must be superior.
In general, I think it's more helpful to just reference the specific language feature you're talking about. Rather than say that JavaScript is a weakly typed language, instead say that there are a lot of implicit type conversations. Rather than say Erlang is strongly typed, say that there is no variable reassignment or shadowing. That way, you avoid the ambiguity about what you actually mean when you talk about strong or weak typing.
My understanding of weak typing is about allowing automatic type conversion. “3” + 1 === “31”, 1 + “3” === 4. Strong typing doesn’t auto convert.
This is one of the more common definitions, yes, but it's not used very consistently. The comment I replied to used a different definition, and I also commonly see the definition that weak typing is the ability to convert a type from one form to another (à la C).
Like I said, if you're going to talk about automatic type conversion, then calling it "automatic type conversion" is probably the simplest option - strong vs weak typing doesn't really need to come into it. Then you avoid any definitional confusion.
Pretty much. There's probably better examples but using some of what's come up here so far: python is strong+dynamic, javascript is weak+dynamic, typescript is weak+static*, java is strong+static.
* Maybe. Not quite sure about "weak" for this one, but I think it makes sense because you can just lie to typescript and then after compilation it just runs as javascript.