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I worry that we’ll now see more broken web apps, given the lack of type safety in Python. I know that JS doesn’t guarantee that either, but at least you can cho

by fortzi 5y ago

I worry that we’ll now see more broken web apps, given the lack of type safety in Python. I know that JS doesn’t guarantee that either, but at least you can choose to work with TypeScript. True, there’s mypy and alike, but their hard to integrate into existing projects, and are also not perfect.

weatherlite 5y ago
People who want Python on the browser would have probably not chosen Typescript anyway, it's mostly not the same demographic. Not everyone cares about types.
- zo1 5y ago
  At this point, as a Python dev, I wouldn't even bother. The web is dirty and unless you have huge community mindshare or oodles of funding (a-la Google), you're not going to get any meaningful traction with whatever python-based UI framework you create. The JS community (funded by big players like Google and Facebook and 20 million liters of starbucks hipster coffee) has figured out all the tooling, libraries, and practically taken over every facet of the web development ecosystem so it caters for JS, that it's going to be severely impractical and hopeless to jump in at this point.
KolenCh 5y ago
Sorry, don’t quite follow, why would the lack of type safety in Python make this a problem, and how would Typescript help in this situation? This comes from Python dev with no idea how to make web app. Eg I’ve seen some package not maintained for years in PyPI while continue to work fine. Also I think Python is strongly typed while js isn’t. I would think that’s a bigger problem?
- derangedHorse 5y ago
  Having static types in help programmers make less mistakes by allowing the compiler to perform stronger forms of static analysis. This prevents programmers from accidentally passing in arguments to a function that have types the function was not defined to handle (since the compiler/interpreter will error out). Also "strong typing" is not well-defined across the literature as acknowledged by this one link from Cornell (which lists strong typing as having "the type of every variable and every expression is a syntactic property" and variables that are "used only in ways that respect its type"): https://www.cs.cornell.edu/courses/cs1130/2012sp/1130selfpaced/module1/module1part4/strongtyping.html https://www.cs.cornell.edu/courses/cs1130/2012sp/1130selfpac... You also have lecturers at Carnegie Mellon teaching that strong typing means "Types must by explicitly converted" :https://www.cs.cmu.edu/~07131/f18/topics/extratations/langs.pdf https://www.cs.cmu.edu/~07131/f18/topics/extratations/langs.... Personally I think the historical definitions from Wikipedia are the most concise (it's paraphrased by me as saying "arguments to a function should have the same type as the parameters the function was defined with): https://en.wikipedia.org/wiki/Strong_and_weak_typing https://en.wikipedia.org/wiki/Strong_and_weak_typing In terms of 'strong typing' (with the definition of not being able to do any kinds of implicit type conversions), Python can be seen as weakly typed since there are forms of implicit type conversions like adding different numerical data types together. I would say it has less instances of type implicit type conversions than something like Javascript though, so if there was a metric of "strength" defined that's inversely correlated with the instances of implicit type conversions than I would say Python could be considered "stronger" (although a lot of Javascript quirkiness is removed through the introduction of static types). All that being said, the argument against Python seems to a gripe against implicit and dynamic typing whereas Typescript has neither and instead brings explicit and static typing (the argument doesn't seem web specific).
  - KolenCh 5y ago
    I think I don't disagree with anything you said fundamentally, but the main point in the parent comment is > I worry that we’ll now see more broken web apps, given the lack of type safety in Python. I just don't see why "broken web apps" would be related to "type safety in Python", and how JS/TS solved the issue. Put it in other way, we could forget anything about types and not even having unit tests, and if the first time you deploy it, it works, with sensible deployment you should expect them to work "perpetually". That's why I mentioned that some unmaintained package in PyPI continues to work for years, because Python 3.x doesn't break backward compatibility. And if they should worry about compatibility with any dependencies, "pinning" to fixed versions or minor versions is better practice. (I know it doesn't solve all problems, and ideally people should keep maintaining them. But again the statement is about "broken web apps" and "type safety".) P.S. Python as strongly-typed language is about say `1 + "2"` situation, where JS seems to allow but not so in Python (although Python's object/data model can handle them via `__add__`). Rebinding a name to another variable is ok in Python, but is a separate feature/characteristics. Also, while I don't know TS, from other comments here it seems that type hints can be more powerful in some cases, if not strictly more powerful. I'm a believer in type hints when using Python and I find it very useful (and recent Python versions are making them more and more powerful.) It is more flexible than static typing but is still useful in performing static analysis, which has detected bugs in my program even when it passes unit tests. (Often it is related to sloppiness rather than "real" bugs though. Having good types make reasoning about the program more easily.) Lastly, runtime type check is a thing in Python too. E.g. I think it is very common for the `__init__` to perform runtime type checking. And then there's some packages allowing you to define a schema where the library would perform runtime type check automatically given the schema.
madacol 5y ago
type hints[0], mypy[1] provide type annotations to python And type hints is something that JS lacks. How many times I've tried to copy paste typescript code to nodejs/browser console and fail miserably [0] https://docs.python.org/3/library/typing.html https://docs.python.org/3/library/typing.html [1] http://mypy-lang.org/ http://mypy-lang.org/
z3t4 5y ago
type annotations does not guarantee correctness, performance, nor does it make your code bug free. Type annotations however helps when writing code, as the tooling will know that something annotated as type X have these prototype variables, or that the object annotated with interface should (but does not guarantee) to have the annotated interface members. This can also be achieved via type inference, but inference is more complicated then simply annotating (writing down) the type in the code. Before Typescript some people used to have the type in the variable name, like strName, fltCost, arrPeople. Bugs are detected by running the program in a chaotic environment (live/prod) where there are humans involved. Bugs can also be found by carefully and critically studying the code. Some bugs can also be found by inference or type annotation tooling, or usually when trying to run the code for the first time.

by fortzi 5y ago

weatherlite 5y ago

People who want Python on the browser would have probably not chosen Typescript anyway, it's mostly not the same demographic. Not everyone cares about types.

zo1 5y ago
At this point, as a Python dev, I wouldn't even bother. The web is dirty and unless you have huge community mindshare or oodles of funding (a-la Google), you're not going to get any meaningful traction with whatever python-based UI framework you create. The JS community (funded by big players like Google and Facebook and 20 million liters of starbucks hipster coffee) has figured out all the tooling, libraries, and practically taken over every facet of the web development ecosystem so it caters for JS, that it's going to be severely impractical and hopeless to jump in at this point.

KolenCh 5y ago

Sorry, don’t quite follow, why would the lack of type safety in Python make this a problem, and how would Typescript help in this situation? This comes from Python dev with no idea how to make web app. Eg I’ve seen some package not maintained for years in PyPI while continue to work fine. Also I think Python is strongly typed while js isn’t. I would think that’s a bigger problem?

derangedHorse 5y ago
Having static types in help programmers make less mistakes by allowing the compiler to perform stronger forms of static analysis. This prevents programmers from accidentally passing in arguments to a function that have types the function was not defined to handle (since the compiler/interpreter will error out). Also "strong typing" is not well-defined across the literature as acknowledged by this one link from Cornell (which lists strong typing as having "the type of every variable and every expression is a syntactic property" and variables that are "used only in ways that respect its type"): https://www.cs.cornell.edu/courses/cs1130/2012sp/1130selfpaced/module1/module1part4/strongtyping.html https://www.cs.cornell.edu/courses/cs1130/2012sp/1130selfpac... You also have lecturers at Carnegie Mellon teaching that strong typing means "Types must by explicitly converted" :https://www.cs.cmu.edu/~07131/f18/topics/extratations/langs.pdf https://www.cs.cmu.edu/~07131/f18/topics/extratations/langs.... Personally I think the historical definitions from Wikipedia are the most concise (it's paraphrased by me as saying "arguments to a function should have the same type as the parameters the function was defined with): https://en.wikipedia.org/wiki/Strong_and_weak_typing https://en.wikipedia.org/wiki/Strong_and_weak_typing In terms of 'strong typing' (with the definition of not being able to do any kinds of implicit type conversions), Python can be seen as weakly typed since there are forms of implicit type conversions like adding different numerical data types together. I would say it has less instances of type implicit type conversions than something like Javascript though, so if there was a metric of "strength" defined that's inversely correlated with the instances of implicit type conversions than I would say Python could be considered "stronger" (although a lot of Javascript quirkiness is removed through the introduction of static types). All that being said, the argument against Python seems to a gripe against implicit and dynamic typing whereas Typescript has neither and instead brings explicit and static typing (the argument doesn't seem web specific).
- KolenCh 5y ago
  I think I don't disagree with anything you said fundamentally, but the main point in the parent comment is > I worry that we’ll now see more broken web apps, given the lack of type safety in Python. I just don't see why "broken web apps" would be related to "type safety in Python", and how JS/TS solved the issue. Put it in other way, we could forget anything about types and not even having unit tests, and if the first time you deploy it, it works, with sensible deployment you should expect them to work "perpetually". That's why I mentioned that some unmaintained package in PyPI continues to work for years, because Python 3.x doesn't break backward compatibility. And if they should worry about compatibility with any dependencies, "pinning" to fixed versions or minor versions is better practice. (I know it doesn't solve all problems, and ideally people should keep maintaining them. But again the statement is about "broken web apps" and "type safety".) P.S. Python as strongly-typed language is about say `1 + "2"` situation, where JS seems to allow but not so in Python (although Python's object/data model can handle them via `__add__`). Rebinding a name to another variable is ok in Python, but is a separate feature/characteristics. Also, while I don't know TS, from other comments here it seems that type hints can be more powerful in some cases, if not strictly more powerful. I'm a believer in type hints when using Python and I find it very useful (and recent Python versions are making them more and more powerful.) It is more flexible than static typing but is still useful in performing static analysis, which has detected bugs in my program even when it passes unit tests. (Often it is related to sloppiness rather than "real" bugs though. Having good types make reasoning about the program more easily.) Lastly, runtime type check is a thing in Python too. E.g. I think it is very common for the `__init__` to perform runtime type checking. And then there's some packages allowing you to define a schema where the library would perform runtime type check automatically given the schema.

madacol 5y ago

type hints[0], mypy[1] provide type annotations to python And type hints is something that JS lacks. How many times I've tried to copy paste typescript code to nodejs/browser console and fail miserably [0] https://docs.python.org/3/library/typing.html https://docs.python.org/3/library/typing.html [1] http://mypy-lang.org/ http://mypy-lang.org/

z3t4 5y ago

type annotations does not guarantee correctness, performance, nor does it make your code bug free. Type annotations however helps when writing code, as the tooling will know that something annotated as type X have these prototype variables, or that the object annotated with interface should (but does not guarantee) to have the annotated interface members. This can also be achieved via type inference, but inference is more complicated then simply annotating (writing down) the type in the code. Before Typescript some people used to have the type in the variable name, like strName, fltCost, arrPeople. Bugs are detected by running the program in a chaotic environment (live/prod) where there are humans involved. Bugs can also be found by carefully and critically studying the code. Some bugs can also be found by inference or type annotation tooling, or usually when trying to run the code for the first time.