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No multiline lambda is a feature. It is convenient enough to use it like in

    sort(items, key=lambda x: x.size)
but really anything much bigger should have a name stamped on it dammit. I find JS largely unintelligible due to lambda overuse and nesting.


no it's not -- every other languages other than JS/TS has multiline lambdas... Java 8+, Kotlin, Rust, Scala, C#, ...

seems you're confused between "limitation" and "feature"...

it's a limitation due to python's "no-braces/indentations-only" policy -- can't think of a way to mark where a lambda starts and ends clearly and cleanly with indentation-only...


Disallowing multiline-lambdas was an intentional choice by the creators to prevent overly-functional code. For the same reasons that map/filter/reduce aren't in the global namespace anymore.

Python prefers different tools (comprehensions) to accomplish most of the same goals.


I mean, yeah, maybe that's the reason, I don't know. Still, I see no reason why you'd split features and limitations into two distinct sets.

In Rust it's difficult to mess with memory: it's a limitation but also a feature. In Haskell you cannot mutate, a limitation if there ever was one, but also a feature.


woah another rustacean? hi there!

for rust, it counts as a 'feature' because it provides safety guarantee, and they're opt-in (can use unsafe)

as for haskell, that immutability also provides guarantee of 'referential-transparency', which the users/libraries can use to their advantange.

But in python's case, you have to define the multi-line function *outside* the chaining, and 'forcing to name things' isn't always good (especially for constantly-changing code)

def hideEmail(user): return { ...user, email: user.hideEmail? '': user.email, }

users.map(hideEmail)

// later: def hideEmailAndPhone(user): return { ...user, email: user.hideEmail? '': user.email, phoneNo: ... // same stuff }

users.map(hideEmailAndPhone) ---

As for JS/TS, you can have 'named-callback-fn':

users.map(function hidePrivateFields(user) { ... })

and it's not difficult to come up with 'named-lambda-fn' standard

users.map(hidePrivateFields(user) => { ... })




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