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Even if it doesn’t help to find bugs, static typing is still worth it. I’ve been fixing some stuff in an existing Python codebase in the last weeks. Most of the

Even if it doesn’t help to find bugs, static typing is still worth it. I’ve been fixing some stuff in an existing Python codebase in the last weeks. Most of the time, when I see a new function, I have no idea what’s the type of its parameters...

mrfusion 8y ago
I like to think of python as a language that’s great for responsible adults. If everyone is a good engineer and comments things and tests things you’re going to have a great time. But if you start getting bad practices they’re going to be multiplied.
- johnfn 8y ago
  Heh. I’d counterargue by asking how many times you’ve heard of someone joining a new job and looking at the code and saying, “Ah, this is clearly written by responsible adults!”
  - Daishiman 8y ago
    Don't be cynical; I've definitely looked for work in companies that have good codebases.
- doktrin 8y ago
  > I like to think of python as a language that’s great for responsible adults. Not a disagreement, but an observation : verbatim the exact same thing has been said about Ruby, and - I imagine - every other widely used dynamically typed language on the planet. IMO, maintainability is a well understood weakness of dynamic typing - hence every responsible Ruby/Python/JS/Perl codebase including a mountain of unit tests that do nothing but cover typing (in addition to the rest of the tests that would be present irrespective of implementation language) At the end of the day there's no silver bullet : either we let the compiler handle type checking, or we cover it ourselves with unit tests. Doing neither isn't really much of an option, but it is probably where a lot of these type-related bugs come from.
- weberc2 8y ago
  You also have to unfailingly keep comments up to date. Our org struggles a lot with this, but I wouldn’t say we are irresponsible apart from the fact that we’re using a language that makes humans do error-prone tasks that are already solved by automation. :)
dasm 8y ago
I have very strong opinions on docstrings; they are simple to implement and completely solve this issue.
- macintux 8y ago
  I wouldn’t say “completely”, because they’re not guaranteed to be accurate, even when first created, much less down the road.
  - yyyymmddhhmmss 8y ago
    Listing arguments and their types in docstrings always feels likea bad idea for this reason.
sonnyblarney 8y ago
"static typing is still worth it. " Or maybe 'flex typing' as we have in TS. I love that TS has 'any' type, because it really allows for some flex in development when you 'haven't figured the dam type out yet' - OR - you're dealing with untyped JSON-ish data. A completed system has 'strong typing'. But a system is always in development. You're trying to do A, but in the meantime, B, C and D need types! And you didn't even know C and D needed to exist. Oops! So you can tweak tsc to be a little lose with the facts and then as the module matures, tighten it up. It's actually kind of interesting that TSC is one of the few 'compilers' (yea I know it's a transpiler) that actually gives you that amount of power over things.
- int_19h 8y ago
  C# has "dynamic", which is similar in spirit.
- machiaweliczny 8y ago
  I use TS with transpileOnly flag (compile even if type errors). This is great, because I can prototype fast even if thing's don't yet typecheck and when I have idea what I'm trying to a chieve I can document all code and polish rough cases without leaving the editor.
crdoconnor 8y ago
I usually write code in the ipython console and copy it back once it's in a fit state. Type lookup in that environment is trivial.
Alex3917 8y ago
> Most of the time, when I see a new function, I have no idea what’s the type of its parameters... For that reason I usually use types for defining utility functions that get re-used in multiple places throughout the app. For everything else I just name the variables according to what the thing is, e.g.: user_model, user_model_list, user_id_set, user_id_to_user_model_dict, etc. If you have a good style guide, there really should only be one allowable name for any given variable, and it should be immediately clear what type each variable is from the suffix on the name.
- cstejerean 8y ago
  Ah yes, the old Hungarian notation (or variation on that idea). Makes sense in some contexts.
- kaoD 8y ago
  Isn't that just ad-hoc typing? What's the point of naming based on types, instead of just declaring types so they can be programmatically analyzed by your tools?
  - Alex3917 8y ago
    > What's the point of naming based on types More readable. When declaring a type you only see the type when the variable is declared or when it's passed into a function, whereas when putting the type in the name it's obvious in each line where it's used so you don't need to waste working memory on remembering what things are.
cstejerean 8y ago
If you’re using a new enough version of Python 3 then you can add type annotations now. Not great by any means but it’s made working with a large-ish python codebase tolerable (together with PyCharm).
Guthur 8y ago
And so how can you even be sure it does what you think. The types are only part of the equation.
xkgihu7r 8y ago
That's what Hungarian notation is for.

mrfusion 8y ago

I like to think of python as a language that’s great for responsible adults. If everyone is a good engineer and comments things and tests things you’re going to have a great time. But if you start getting bad practices they’re going to be multiplied.

johnfn 8y ago
Heh. I’d counterargue by asking how many times you’ve heard of someone joining a new job and looking at the code and saying, “Ah, this is clearly written by responsible adults!”
- Daishiman 8y ago
  Don't be cynical; I've definitely looked for work in companies that have good codebases.
doktrin 8y ago
> I like to think of python as a language that’s great for responsible adults. Not a disagreement, but an observation : verbatim the exact same thing has been said about Ruby, and - I imagine - every other widely used dynamically typed language on the planet. IMO, maintainability is a well understood weakness of dynamic typing - hence every responsible Ruby/Python/JS/Perl codebase including a mountain of unit tests that do nothing but cover typing (in addition to the rest of the tests that would be present irrespective of implementation language) At the end of the day there's no silver bullet : either we let the compiler handle type checking, or we cover it ourselves with unit tests. Doing neither isn't really much of an option, but it is probably where a lot of these type-related bugs come from.
weberc2 8y ago
You also have to unfailingly keep comments up to date. Our org struggles a lot with this, but I wouldn’t say we are irresponsible apart from the fact that we’re using a language that makes humans do error-prone tasks that are already solved by automation. :)

dasm 8y ago

I have very strong opinions on docstrings; they are simple to implement and completely solve this issue.

macintux 8y ago
I wouldn’t say “completely”, because they’re not guaranteed to be accurate, even when first created, much less down the road.
- yyyymmddhhmmss 8y ago
  Listing arguments and their types in docstrings always feels likea bad idea for this reason.

sonnyblarney 8y ago

"static typing is still worth it. " Or maybe 'flex typing' as we have in TS. I love that TS has 'any' type, because it really allows for some flex in development when you 'haven't figured the dam type out yet' - OR - you're dealing with untyped JSON-ish data. A completed system has 'strong typing'. But a system is always in development. You're trying to do A, but in the meantime, B, C and D need types! And you didn't even know C and D needed to exist. Oops! So you can tweak tsc to be a little lose with the facts and then as the module matures, tighten it up. It's actually kind of interesting that TSC is one of the few 'compilers' (yea I know it's a transpiler) that actually gives you that amount of power over things.

int_19h 8y ago
C# has "dynamic", which is similar in spirit.
machiaweliczny 8y ago
I use TS with transpileOnly flag (compile even if type errors). This is great, because I can prototype fast even if thing's don't yet typecheck and when I have idea what I'm trying to a chieve I can document all code and polish rough cases without leaving the editor.

crdoconnor 8y ago

I usually write code in the ipython console and copy it back once it's in a fit state. Type lookup in that environment is trivial.

Alex3917 8y ago

> Most of the time, when I see a new function, I have no idea what’s the type of its parameters... For that reason I usually use types for defining utility functions that get re-used in multiple places throughout the app. For everything else I just name the variables according to what the thing is, e.g.: user_model, user_model_list, user_id_set, user_id_to_user_model_dict, etc. If you have a good style guide, there really should only be one allowable name for any given variable, and it should be immediately clear what type each variable is from the suffix on the name.

cstejerean 8y ago
Ah yes, the old Hungarian notation (or variation on that idea). Makes sense in some contexts.
kaoD 8y ago
Isn't that just ad-hoc typing? What's the point of naming based on types, instead of just declaring types so they can be programmatically analyzed by your tools?
- Alex3917 8y ago
  > What's the point of naming based on types More readable. When declaring a type you only see the type when the variable is declared or when it's passed into a function, whereas when putting the type in the name it's obvious in each line where it's used so you don't need to waste working memory on remembering what things are.

cstejerean 8y ago

If you’re using a new enough version of Python 3 then you can add type annotations now. Not great by any means but it’s made working with a large-ish python codebase tolerable (together with PyCharm).

Guthur 8y ago

And so how can you even be sure it does what you think. The types are only part of the equation.

xkgihu7r 8y ago

That's what Hungarian notation is for.